BRK Ghost Review
- Thread starter Franklink
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The two I've handled/am aware of came from BRK with trigger weights in the 1lb, 4oz range, as OEM, measured as delivered. The 1lb, 4oz I cite was a 10 shot average with a Lyman digital trigger pull gauge (photos earlier in this review).
The adjustments to the trigger mentioned in the manual on page 12 can make the trigger feel much better, but won't lighten it much (in my experience).
Both the review Ghost I have and Arzrover's required lightening of springs to get the trigger down into the 6-8ounze area. We also both made adjustments as shown above, to get the triggers the way we like them.
While Arzrover went the more elegant route of actually replacing the two springs that I will mention now for lighter ones, I went a more crude route. I removed the spring above the "B" arrow above and compressed it, quite forcibly, in needle nose plyers. That helped get a reduction in first stage.
The biggest gains to be had in helping the trigger are on what we've been calling the trigger bar return spring, circled here...
And a photo of that spring.
This is how the trigger cassette "catches" that bar.
I hate to clip a spring, much preferring to replace with lighter springs so that both ends are finished, but after a failed attempt at sourcing a lighter trigger bar return spring, I did the dastardly deed. I only clipped half a coil at a time, and then reassembled to test the trigger weight.
WARNING-I cannot recommend anyone attempt this!!! If you don't use heat to counteract the thread lock on the brass "eared" piece, you WILL DESTROY IT. (don't ask how I know). And even with heat, that thread lock is serious business. I don't think BRK intended for this to be a user-serviceable part, so fair warning. For the most intrepid, it might be safer to clip coils with wire snips, while leaving the brass piece threaded onto the bar, and then bending each coil off of the bar with needle nose plyers on both side of the snipped coil. Even with that process, you run a high risk of messing something up.
It is also tricky to get that brass piece threaded back on to the exact depth required for the trigger to function properly. So, if you're brave enough to try, take careful measurements.
I also applied a small amount of moly to each of the contact points in the trigger, here are a few of them. It has migrated a bit and looks like more than I originally intended.
I did no stoning or polishing of any contact points anywhere in the mechanism.
Trigger on the Ghost in my possession breaks quite crisply at 6-7ounces now. It is at a point that the trigger isn't making accuracy difficult, as I find some heavy, gritty, or unpredictable triggers can do.
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.22 barrel, various reg pressures with 0.047 wire hammer spring from .177 Carbine
I was really hoping to arrive at the desired fps prior to this post, but I'm getting too many data/notes and want to get it posted prior to memory getting fuzzy from too many details. So, spoiler alert: I'm not at desired fps with the .22 barrel yet.
This type of technical stuff may be boring for some, but if you are considering buying the gun and/or generally curious about how to get the most out of a the Ghost platform and also want to understand the physics behind how it works, careful reading of the following may prove beneficial. I understand that it gets a bit cumbersome to process the data in written format like this, it is even more so to collect it. I do it because of the educational value, to myself, and hopefully others.
All of the following chronograph readings are with 25.4gr .22 Monster RDs, as that is the desired projectile (crossing fingers that the barrel likes some of the batches that I have on hand once I get to the accuracy testing phase). Hoping to get them going around 950fps (roughly 50fpe) as that has proven to be a great starting speed for these pellets from numerous Daystate LW polygonal barrels.
I was told 140 bar reg pressure should net me around 50fpe (950fps) with the 23inch .22 barrel, so I started there.
I'll present this in the order they were shot, and try to explain the thought process that led to that sequence.
142 BAR (needle on reg gauge slightly past 140 but not halfway between 140 and 150)
minimum hammer spring preload: 556.7, 575.5, 575.6, 571.9, 565.5 - ES of 18.85
maximum hammer spring preload: 818.4, 826.8, 830.3, 830.1, 831.7 - ES 13.32
Hmmm, that was more like 38-39fpe, not 50fpe. Maybe more reg pressure?
155 BAR
maximum hammer spring preload: 820.1, 816.3, 816.4, 818, 816, 8111.9 - ES of 8.2
HUH!?!?! power went down with more reg pressure....So, maybe this pseudo-balanced valve doesn't like a reg pressure too high?
125 BAR
maximum hammer spring preload: 848.5, 854.7, 859.6, 857.1, 861.6- ES of 13.1
Okay, so that's more like 41fpe, but still not the 50. Interesting....so if I go down further will the fpe climb further? Lets see!
95 BAR
maximum hammer spring preload: 836.3, 833.9, 836, 834.4, 832.5- ES of 3.86
Well, power fell so maybe I went down too far on the regulator pressure?
105BAR
minimum hammer spring preload: 659.6, 662.5, 654.2, 669.2, 666.9 - ES of 9.99
maximum hammer spring preload: 854.8, 856, 856.2, 853.9, 853- ES of 3.2
Okay, all of the above seemed like a pretty decent window of regulator pressures to achieve the desired velocity. Even with the max fpe output at around 125 bar, I'm almost 100fps less than what I should be seeing, which is disappointing. I even got out a HW springer that is as reliable as the sun coming up every morning to produce 710-715 in order to test my chronograph. HW springer produced 710-715fps so no wonky chrono.
On a positive note, that hammer spring preload adjustment can produce an fps range of roughly 250fps at certain regulator pressures, with certain hammer springs, and specific barrels (caliber). Some comments sounded disappointed with how small of a gap I was seeing from MIN and MAX with the .177 barrel. This should make those individuals happy.
The above testing is what Arzrover referred to when he commented a day or two ago that I wasn't getting desired fps with the .22 barrel. We discussed it a bit. Me wondering aloud to him if the .177 Carbine is valved differently, and concerned that it is. He feels they all have the same valve and he also had some other thoughts. The first of which is that the maybe I have the threaded end of the hammer too recessed into the hammer body so that I'm getting hammer on valve body contact, stealing some of the potential energy imparted to the valve stem (versus all of the kinetic energy of the hammer being imparted solely on the valve stem.).
Here are some photos to illustrate that line of thought. (as previously stated, this level of disassembly is not necessary to make the adjustments, but by doing so I can take photos to help readers visualize the adjustments being made).
All of the above chrono testing was done with this depth....
Without the nose extended, the thought being that where I marked green is perhaps "hitting" (hammer on valve body, not hammer solely on valve stem).
The testing from here on will be done with this depth....
Note the potentially "cleaner" tap of the hammer on the valve stem with the slightly protruding "nose"....
So I extended the threaded "nose" of the hammer about 1/8th of an inch (effectively decreasing the stroke length but also allowing all of the energy from the hammer to be imparted solely upon the valve stem, and not the valve body).
We also discussed the wire size of the hammer spring I have been using. When he was sent the Ghost earlier this year for testing/tuning purposes, it came with full length .22 and .25 barrels and with various hammer springs. The one BRK labeled "light" had a wire size of 0.046inches. "Heavy" was 0.051. "Extra Heavy" was 0.057.
So I put some calipers on the two hammer springs in my possession. The one that came installed in the .177 Carbine has a wire size of 0.047 (close to what BRK calls the "light"). And the one Arzrover sent with me last weekend at the ft match measures in at 0.051, which would be a BRK rating of "heavy." He told me the 0.051 is the spring that'll do 50fpe in .22 with a reg pressure of 140 bar. BUT, not wanting to change two variables at once and never knowing which got us more power, I concluded that I needed to do another chrono session prior to going to the 0.051 spring. The question to be answered, "could extending that threaded "nose" of the hammer slightly increase the energy output via a "cleaner" tap on the valve stem?" So back to the chrono.
The following three reg pressures were still with hammer spring of 0.047 wire "light."
Still at 105 bar from the previous day's chrono session (above)
maximum hammer spring preload: 864, 874, 867.7, 863.3, 867.7 - ES of 10.72
Okay, the extension of the threaded hammer "nose" was worth a gain of about 10fps.....inconclusive. Lets see if there's a more distinct effect at the other reg pressures I tested at yesterday
125 BAR
maximum hammer spring preload: 877.8, 872.8, 874.5, 871.7, 872.3, - ES 2.77
Okay! That's the most power the gun has produced with this spring. So, there is something to that hypothesis that we get a cleaner tap on the valve stem with the threaded hammer "nose" slightly extended. This was about 15fps more than 125bar reg pressure produced with the same hammer spring and the threaded hammer nose flush/not extended.
Now lets go back up to 140 bar and see the effect....
140 BAR
maximum hammer spring preload: 843.1, 849.4, 844, 849.7, 846.5 - ES of 6.6
Compared to the 142bar with the fully recessed nose of the hammer, we're still seeing that trend of a gain of roughly 15fps.
Hmmm.. same trend I saw before. So, we can conclude at this point that the "light" hammer spring (wire size of 0.047) will produce about 43fpe, and surprisingly enough, a higher reg pressure proves detrimental to power output with THIS barrel, and THIS pellet, and THIS hammer spring.
A couple takeaways....
I was really hoping to arrive at the desired fps prior to this post, but I'm getting too many data/notes and want to get it posted prior to memory getting fuzzy from too many details. So, spoiler alert: I'm not at desired fps with the .22 barrel yet.
This type of technical stuff may be boring for some, but if you are considering buying the gun and/or generally curious about how to get the most out of a the Ghost platform and also want to understand the physics behind how it works, careful reading of the following may prove beneficial. I understand that it gets a bit cumbersome to process the data in written format like this, it is even more so to collect it. I do it because of the educational value, to myself, and hopefully others.
All of the following chronograph readings are with 25.4gr .22 Monster RDs, as that is the desired projectile (crossing fingers that the barrel likes some of the batches that I have on hand once I get to the accuracy testing phase). Hoping to get them going around 950fps (roughly 50fpe) as that has proven to be a great starting speed for these pellets from numerous Daystate LW polygonal barrels.
I was told 140 bar reg pressure should net me around 50fpe (950fps) with the 23inch .22 barrel, so I started there.
I'll present this in the order they were shot, and try to explain the thought process that led to that sequence.
142 BAR (needle on reg gauge slightly past 140 but not halfway between 140 and 150)
minimum hammer spring preload: 556.7, 575.5, 575.6, 571.9, 565.5 - ES of 18.85
maximum hammer spring preload: 818.4, 826.8, 830.3, 830.1, 831.7 - ES 13.32
Hmmm, that was more like 38-39fpe, not 50fpe. Maybe more reg pressure?
155 BAR
maximum hammer spring preload: 820.1, 816.3, 816.4, 818, 816, 8111.9 - ES of 8.2
HUH!?!?! power went down with more reg pressure....So, maybe this pseudo-balanced valve doesn't like a reg pressure too high?
125 BAR
maximum hammer spring preload: 848.5, 854.7, 859.6, 857.1, 861.6- ES of 13.1
Okay, so that's more like 41fpe, but still not the 50. Interesting....so if I go down further will the fpe climb further? Lets see!
95 BAR
maximum hammer spring preload: 836.3, 833.9, 836, 834.4, 832.5- ES of 3.86
Well, power fell so maybe I went down too far on the regulator pressure?
105BAR
minimum hammer spring preload: 659.6, 662.5, 654.2, 669.2, 666.9 - ES of 9.99
maximum hammer spring preload: 854.8, 856, 856.2, 853.9, 853- ES of 3.2
Okay, all of the above seemed like a pretty decent window of regulator pressures to achieve the desired velocity. Even with the max fpe output at around 125 bar, I'm almost 100fps less than what I should be seeing, which is disappointing. I even got out a HW springer that is as reliable as the sun coming up every morning to produce 710-715 in order to test my chronograph. HW springer produced 710-715fps so no wonky chrono.
On a positive note, that hammer spring preload adjustment can produce an fps range of roughly 250fps at certain regulator pressures, with certain hammer springs, and specific barrels (caliber). Some comments sounded disappointed with how small of a gap I was seeing from MIN and MAX with the .177 barrel. This should make those individuals happy.
The above testing is what Arzrover referred to when he commented a day or two ago that I wasn't getting desired fps with the .22 barrel. We discussed it a bit. Me wondering aloud to him if the .177 Carbine is valved differently, and concerned that it is. He feels they all have the same valve and he also had some other thoughts. The first of which is that the maybe I have the threaded end of the hammer too recessed into the hammer body so that I'm getting hammer on valve body contact, stealing some of the potential energy imparted to the valve stem (versus all of the kinetic energy of the hammer being imparted solely on the valve stem.).
Here are some photos to illustrate that line of thought. (as previously stated, this level of disassembly is not necessary to make the adjustments, but by doing so I can take photos to help readers visualize the adjustments being made).
All of the above chrono testing was done with this depth....
Without the nose extended, the thought being that where I marked green is perhaps "hitting" (hammer on valve body, not hammer solely on valve stem).
The testing from here on will be done with this depth....
Note the potentially "cleaner" tap of the hammer on the valve stem with the slightly protruding "nose"....
So I extended the threaded "nose" of the hammer about 1/8th of an inch (effectively decreasing the stroke length but also allowing all of the energy from the hammer to be imparted solely upon the valve stem, and not the valve body).
We also discussed the wire size of the hammer spring I have been using. When he was sent the Ghost earlier this year for testing/tuning purposes, it came with full length .22 and .25 barrels and with various hammer springs. The one BRK labeled "light" had a wire size of 0.046inches. "Heavy" was 0.051. "Extra Heavy" was 0.057.
So I put some calipers on the two hammer springs in my possession. The one that came installed in the .177 Carbine has a wire size of 0.047 (close to what BRK calls the "light"). And the one Arzrover sent with me last weekend at the ft match measures in at 0.051, which would be a BRK rating of "heavy." He told me the 0.051 is the spring that'll do 50fpe in .22 with a reg pressure of 140 bar. BUT, not wanting to change two variables at once and never knowing which got us more power, I concluded that I needed to do another chrono session prior to going to the 0.051 spring. The question to be answered, "could extending that threaded "nose" of the hammer slightly increase the energy output via a "cleaner" tap on the valve stem?" So back to the chrono.
The following three reg pressures were still with hammer spring of 0.047 wire "light."
Still at 105 bar from the previous day's chrono session (above)
maximum hammer spring preload: 864, 874, 867.7, 863.3, 867.7 - ES of 10.72
Okay, the extension of the threaded hammer "nose" was worth a gain of about 10fps.....inconclusive. Lets see if there's a more distinct effect at the other reg pressures I tested at yesterday
125 BAR
maximum hammer spring preload: 877.8, 872.8, 874.5, 871.7, 872.3, - ES 2.77
Okay! That's the most power the gun has produced with this spring. So, there is something to that hypothesis that we get a cleaner tap on the valve stem with the threaded hammer "nose" slightly extended. This was about 15fps more than 125bar reg pressure produced with the same hammer spring and the threaded hammer nose flush/not extended.
Now lets go back up to 140 bar and see the effect....
140 BAR
maximum hammer spring preload: 843.1, 849.4, 844, 849.7, 846.5 - ES of 6.6
Compared to the 142bar with the fully recessed nose of the hammer, we're still seeing that trend of a gain of roughly 15fps.
Hmmm.. same trend I saw before. So, we can conclude at this point that the "light" hammer spring (wire size of 0.047) will produce about 43fpe, and surprisingly enough, a higher reg pressure proves detrimental to power output with THIS barrel, and THIS pellet, and THIS hammer spring.
A couple takeaways....
- It is impressive that the valve can not only go from 20 to 40fpe, but do so with the same hammer spring AND be acceptably consistent at each.
- Extending out that threaded nose of the hammer roughly 1/8th of an inch produces a "cleaner" tap on the valve stem, and was worth 10-15fps across all three reg pressures I compared.
- The 0.051" wire spring should be pay dirt for the 950fps with a reg pressure of 140bar
- It seems that he inability to get to the 950fps with .22 Monster RDs like Arzrover has seen is simply because I've been using a weaker hammer spring than he used to achieve that velocity, not differences in the valve of the .177 Carbine as I feared.
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@Franklink - I'll retest my 22 cal (23" barrel) but fairly certain it's running around 938 FPS @ 140 bar with PW set at 10. It came set at 160 bar running 987 FPS. By the way, this was all with the JSB RD. Hope this helps with the testing.
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Yes sir! Very helpful info. hoping I'm in that range of 938-950 with the Monster RD. Thank you.
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EDventure... that is about exactly where mine seems most accurate...
@Franklink... another note ... your "light" spring should work well for 15.89s, 18.1s, 21s, and 20.2 slugs... in addition to all the 177 stuff. I think the 177 HP barrel plus attention to that barrels port, would drive most everything 177 well except maybe the 20.2 slugs.
Also, I spent a couple of hours with my trigger assembly completely apart last night to see if it could be better... I like light triggers. Changed the front trigger return spring and polished a bit and adjusted. It's now 1 oz first stage and 7.8 oz total. I might go back to a slightly heavier front spring as the difference in stages is too much but it feels very good now.
Anyone changing springs on this should PAY ATTENTION to @Franklink's warnings.
Bob
@Franklink... another note ... your "light" spring should work well for 15.89s, 18.1s, 21s, and 20.2 slugs... in addition to all the 177 stuff. I think the 177 HP barrel plus attention to that barrels port, would drive most everything 177 well except maybe the 20.2 slugs.
Also, I spent a couple of hours with my trigger assembly completely apart last night to see if it could be better... I like light triggers. Changed the front trigger return spring and polished a bit and adjusted. It's now 1 oz first stage and 7.8 oz total. I might go back to a slightly heavier front spring as the difference in stages is too much but it feels very good now.
Anyone changing springs on this should PAY ATTENTION to @Franklink's warnings.
Bob
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I got my .177 HP yesterday afternoon and have not had time to do much testing. It came with the reg set at 138 bar and I set the tension to MAX. Ten 16.2 JSBs averaged 910 FPS. 9FPS max spread, S.D. of 2 for 30 FPE. I had 18 mph winds gusting to 25 from right to left and still got decent groups at 50. The trigger breaks clean, but is way to heavy. I am going to work on that now.
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Here is a close-up of the PRS rail extension on the BRK Ghost - as shown at the Ghost press day on October 3rd. It features picatinny and ARCA rail. This was fitted to the .30 cal.
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L
You are spoiling us with your awesome deep dives into the Ghost , a big thanks for taking the time.
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0.051" wire spring and .22 barrel, chronograph results
No change other than swapping out the 0.047 hammer spring for the 0.051 hammer spring (threaded hammer tip is still extended about 1/8")
And this is all still with .22 Monster RDs (known junky batches in the accuracy dept make for good chrono sessions
, gotta save the good stuff)
140 BAR
minimum preload: 670.8, 674.9, 679.2, 679.2, 676.5 for ES of 8.4
max preload: 920.6, 924.6, 921.5, 927.1, 925.4 for ES of 6.48
Well, that's about 30fps less than we were expecting......The trend with all of the previous chrono sessions with the .22 barrel has been that a reg pressure of 120-130 bar produces the most energy.....guess I'll go down in reg pressure and see if speed/energy goes up.
115 BAR
max preload: 899.5, 900.7, 897.7, 899.3, 898 for ES of 3
Not what I'm looking for....I'll bump it I guess...
128 BAR (needle just under 130 but not halfway between 120 and 130)
max preload: 930.9, 929.9, 931.2, 929.2, 926.8 for ES of 4.4
min preload: 704.9, 711.7, 708.5, 711.5, 716.7 for ES of 12
50% preload: 846.2, 846.8, 845.5, 846.6, 854 for ES of 8.5
So, 930fps with max hammer spring preload is good for about 930fps with .22/25.4grain MRDs, which puts us at 48.8 foot pounds, and still not quite where I'm told it should be.
As previously noted, Arzover has the most experience with the Ghost platform of anyone that I have quick access to. He's been essentially doing R&D with one in both .22 and .25 since at least late spring. So, as I often do, I shot him a text right after the above chronograph session: "maxed out @930fpe with MRDs, using the heavier hammer spring, I'm happy with that." And I am. I've been competing in this long range field target game with .22 MRDs going from 860-900fps for about 2 years from my personal gun (rebarrelled Veteran Long). I've done okay, won a monthly match, had a couple other monthly matches where I was tied for high score or in the top 4 or 5 highest scores but I'm not consistently lighting the world on fire with my scores. My best high power field target showing was a recent 3rd place at the Extreme Field Target portion of EBR in Sportsman (.22) class a few weeks ago. I've felt like I've been severely undergunned with the Veteran and the MRDs going that slow, as the majority of .22 MRD shooters are pushing them 930+, and many of the .25 and up shooters are in the 70, 80, 90fpe realm. And since long range field target is what I have my sights set on for the .22 barrel in the Ghost.....to go from my usual 890 fps with MRDs for just under 45fpe, up to almost 49fpe with them going 930 from the Ghost, a gain of 40fps.....yes I was pleased.
Arzrover texted back though: "Can you chat for just a moment?" So I dialed him up and this is how it went. His first comment....it should be putting out more oomph than this, and not just a little more. "That valve is SO easy to knock open, and pushes so much air!" He says, He thought he was remembering the 950fps with MRDs with the hammer tension around 15 or 16 and a reg pressure of 140 bar, and there's of course 4 more degrees of hammer tension above that, he threw the 970fps number out there. As polite and gracious as he always is, he carefully asked me a few questions to ensure that we're not dealing with operator error here. His first question was if I have the barrel lined up in the chassis correctly. His thoughts there were that if I have the barrel slightly turned it might be blocking a small portion of the transfer port, thereby robbing power. I responded by telling him I took the grub screw all the way out when I installed the barrel so that I could ensure the divot that the grub screw seats into was centered in the threaded hole for the grub screw. He says that should ensure that you don't have the barrel slightly skewed. He next asked if I'm hitting max speed at a hammer tension setting less than "MAX." I told him, no, the more hammer tension I give it, the higher the fps goes, even at reg pressure of 128 bar. I pointed out how it's strange that, at all of my chrony sessions, the max energy output has always been around 120-130 bar regulator pressure, and that 140 and above actually produces LESS energy. He agreed that is indeed a head-scratcher. He thinks we need to pull the valve out of the .177 Carbine and compare specs to the valve that came in the .22/.25 R&D Ghost that he's been working with. He also thinks we need to investigate if there is a constriction in the chassis for this .177 Carbine in the air passageway between the valve and the barrel. I am curious as well.
So, yes, I'll probably get around to pulling the valve and comparing specs with Bob, but in the meantime, I'm kind of sick of chrono sessions in the garage! All of my airgun tinkering is with the end goal of shooting. Shooting is the enjoyable part for me. And the tinkering sessions mean I might be able to improve the accuracy and precision in the shooting sessions, so I tolerate (begrudgingly) the tuning. BUT I NEED TO SHOOT a little bit, after all that shooting into a pellet trap junk.
So, before I get around to pulling the valve, I think I'm going to need to shoot this thing a bit at 930fps and see how it does!!!
Honestly, a reg pressure of just under 130 BAR, producing shots at just under 50fpe is more than a bit appealing. That difference of 140 to 128 bar will mean more shots per fill with the current "tune", and this test Ghost still only has the 300cc bottle so more shots per fill is welcome. Also notice that with this tune we're seeing a spread of 220 fps (710-930fps) from MIN to MAX on the hammer spring preload with the .22/25.4grain pellets. That's something like 28fpe all the way up to almost 50. That range of fpe, in .22, has a lot of utility!!! I think with current settings, "MIN" might put out the 18.1gr JSB pellets at about where they should be for SWEETNESS. And I think somewhere around 6-14 on the hammer spring tension adjustment might even get the 17.5grain NSA up into a happy place. And even MAX might put the 20.2grain NSAs into accurate speeds.
As a side-note, I realized throwing this on the rear pic rail would make the barrel horizontal, and easier to line up into the pellet trap. It's meant to be a forward, undermounted pic rail handle but it has made the chrono sessions a bit easier. I might try shooting it this way at paper too, sorta the same concept as the little rear monopods, just not as refined as one meant for the purpose.
(I wonder to myself if Daystate leadership groans inside when I post photos like this one, with my mismatched, homemade, janky accessories crudely slapped onto their pride and joy. lol. As an FYI/disclaimer, they do actually make much better-looking accessories than what I'm presenting here. )
No change other than swapping out the 0.047 hammer spring for the 0.051 hammer spring (threaded hammer tip is still extended about 1/8")
And this is all still with .22 Monster RDs (known junky batches in the accuracy dept make for good chrono sessions
, gotta save the good stuff)140 BAR
minimum preload: 670.8, 674.9, 679.2, 679.2, 676.5 for ES of 8.4
max preload: 920.6, 924.6, 921.5, 927.1, 925.4 for ES of 6.48
Well, that's about 30fps less than we were expecting......The trend with all of the previous chrono sessions with the .22 barrel has been that a reg pressure of 120-130 bar produces the most energy.....guess I'll go down in reg pressure and see if speed/energy goes up.
115 BAR
max preload: 899.5, 900.7, 897.7, 899.3, 898 for ES of 3
Not what I'm looking for....I'll bump it I guess...
128 BAR (needle just under 130 but not halfway between 120 and 130)
max preload: 930.9, 929.9, 931.2, 929.2, 926.8 for ES of 4.4
min preload: 704.9, 711.7, 708.5, 711.5, 716.7 for ES of 12
50% preload: 846.2, 846.8, 845.5, 846.6, 854 for ES of 8.5
So, 930fps with max hammer spring preload is good for about 930fps with .22/25.4grain MRDs, which puts us at 48.8 foot pounds, and still not quite where I'm told it should be.
As previously noted, Arzover has the most experience with the Ghost platform of anyone that I have quick access to. He's been essentially doing R&D with one in both .22 and .25 since at least late spring. So, as I often do, I shot him a text right after the above chronograph session: "maxed out @930fpe with MRDs, using the heavier hammer spring, I'm happy with that." And I am. I've been competing in this long range field target game with .22 MRDs going from 860-900fps for about 2 years from my personal gun (rebarrelled Veteran Long). I've done okay, won a monthly match, had a couple other monthly matches where I was tied for high score or in the top 4 or 5 highest scores but I'm not consistently lighting the world on fire with my scores. My best high power field target showing was a recent 3rd place at the Extreme Field Target portion of EBR in Sportsman (.22) class a few weeks ago. I've felt like I've been severely undergunned with the Veteran and the MRDs going that slow, as the majority of .22 MRD shooters are pushing them 930+, and many of the .25 and up shooters are in the 70, 80, 90fpe realm. And since long range field target is what I have my sights set on for the .22 barrel in the Ghost.....to go from my usual 890 fps with MRDs for just under 45fpe, up to almost 49fpe with them going 930 from the Ghost, a gain of 40fps.....yes I was pleased.
Arzrover texted back though: "Can you chat for just a moment?" So I dialed him up and this is how it went. His first comment....it should be putting out more oomph than this, and not just a little more. "That valve is SO easy to knock open, and pushes so much air!" He says, He thought he was remembering the 950fps with MRDs with the hammer tension around 15 or 16 and a reg pressure of 140 bar, and there's of course 4 more degrees of hammer tension above that, he threw the 970fps number out there. As polite and gracious as he always is, he carefully asked me a few questions to ensure that we're not dealing with operator error here. His first question was if I have the barrel lined up in the chassis correctly. His thoughts there were that if I have the barrel slightly turned it might be blocking a small portion of the transfer port, thereby robbing power. I responded by telling him I took the grub screw all the way out when I installed the barrel so that I could ensure the divot that the grub screw seats into was centered in the threaded hole for the grub screw. He says that should ensure that you don't have the barrel slightly skewed. He next asked if I'm hitting max speed at a hammer tension setting less than "MAX." I told him, no, the more hammer tension I give it, the higher the fps goes, even at reg pressure of 128 bar. I pointed out how it's strange that, at all of my chrony sessions, the max energy output has always been around 120-130 bar regulator pressure, and that 140 and above actually produces LESS energy. He agreed that is indeed a head-scratcher. He thinks we need to pull the valve out of the .177 Carbine and compare specs to the valve that came in the .22/.25 R&D Ghost that he's been working with. He also thinks we need to investigate if there is a constriction in the chassis for this .177 Carbine in the air passageway between the valve and the barrel. I am curious as well.
So, yes, I'll probably get around to pulling the valve and comparing specs with Bob, but in the meantime, I'm kind of sick of chrono sessions in the garage! All of my airgun tinkering is with the end goal of shooting. Shooting is the enjoyable part for me. And the tinkering sessions mean I might be able to improve the accuracy and precision in the shooting sessions, so I tolerate (begrudgingly) the tuning. BUT I NEED TO SHOOT a little bit, after all that shooting into a pellet trap junk.
So, before I get around to pulling the valve, I think I'm going to need to shoot this thing a bit at 930fps and see how it does!!!
Honestly, a reg pressure of just under 130 BAR, producing shots at just under 50fpe is more than a bit appealing. That difference of 140 to 128 bar will mean more shots per fill with the current "tune", and this test Ghost still only has the 300cc bottle so more shots per fill is welcome. Also notice that with this tune we're seeing a spread of 220 fps (710-930fps) from MIN to MAX on the hammer spring preload with the .22/25.4grain pellets. That's something like 28fpe all the way up to almost 50. That range of fpe, in .22, has a lot of utility!!! I think with current settings, "MIN" might put out the 18.1gr JSB pellets at about where they should be for SWEETNESS. And I think somewhere around 6-14 on the hammer spring tension adjustment might even get the 17.5grain NSA up into a happy place. And even MAX might put the 20.2grain NSAs into accurate speeds.
As a side-note, I realized throwing this on the rear pic rail would make the barrel horizontal, and easier to line up into the pellet trap. It's meant to be a forward, undermounted pic rail handle but it has made the chrono sessions a bit easier. I might try shooting it this way at paper too, sorta the same concept as the little rear monopods, just not as refined as one meant for the purpose.
(I wonder to myself if Daystate leadership groans inside when I post photos like this one, with my mismatched, homemade, janky accessories crudely slapped onto their pride and joy. lol. As an FYI/disclaimer, they do actually make much better-looking accessories than what I'm presenting here. )
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Thanks for all your vaulable testing and posting. Did you ever consider that you use all the time the same starting point of the hammer spring for the different springs. I mean this power wheel only changes a certain range based on a starting point of compression of the hammer spring. In case you would tension the hammer spring internally ( or wherever this can be done on the Ghost) and than start all over again with testing the powerwheel setting sthe results would be different. In my books you can never tune a pcp “on the knee” unless you find the plateau. ( max speed at a given reg pressure by maximizing hammer spring) . I do not see how you can check if you are on or close to your plateau with your way of testing. This also means you can not find the max power output per reg setting only with the power wheel . You have to get into the macro adjustment of the hammer spring. Are you with me ?
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Definitely on the .22. That port on Franklink’s barrel is significantly larger than the port on my .22 DW barrel. Probably why I have to crank it up to 3600u-sec and 82 vdc just to get 965 fps with the RDMs.
Nice Dremel work on that .177 port Derrick. ! You also had to port the .22 DW barrel to get decent power didn’t you?
Scott H shot my .22 DW at EBR 75Y qualifier. First day at 965 fps, second day at 945 fps. He thought it was better at the higher speed.
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I just want to say I was wrong, Need to apologize to the people of the BRK GHOST.
I said the gun would not be out for the public until Jan sometime, Man was I wrong and the gun seems to be a super good gun, I have been waiting on a gun from another manufacture for months , Just a little on edge I guess, I hope everyone is enjoying there new gun and a big very big Way to go for the makers if the BRK GHOST, Brocock /Daystate whoever, You said and you delivered, That's a Hugh plus in my book.... I AM WATCHING.
I said the gun would not be out for the public until Jan sometime, Man was I wrong and the gun seems to be a super good gun, I have been waiting on a gun from another manufacture for months , Just a little on edge I guess, I hope everyone is enjoying there new gun and a big very big Way to go for the makers if the BRK GHOST, Brocock /Daystate whoever, You said and you delivered, That's a Hugh plus in my book.... I AM WATCHING.
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I am fully aware that my reviews are long-winded to the point that I fear some get lost by looking at the forest and missing the trees.
All of the chrono sessions that I've reported on are more data sharing than they are "tuning" sessions. I've made no effort to tune "on the knee" (I'm annoyed by that term every time I see it). However, I have made extensive efforts to give people an idea of what to expect from the Ghost Carbine .177 and various pellets (specifically the JSB .177/10.34) and also the .22/23 inch barrel and the 25.4gr Monster RDs, both at various reg pressures with various hammer spring tensions (via preload adjustment) with the weights of hammer spring that I have (both of which are BRK OEM springs owners can expect to have in their guns).
As for your concerns about repeatability in the preload adjustment, (barring any "sag" in the spring, which is usually more of a long-term use problem) this shouldn't be a problem. For example, I could convert back to the .177 barrel adjust the hammer tension, swap back to the 0.047" wire spring, adjust the regulator pressure to 105 bar, and the stroke length the same as I had it before, and it will produce 890-900fps with 10.34grain pellets. That is really the beauty of this platform, the repeatability in the settings.
You also state, "This also means you can not find the max power output per reg setting only with the preload adjustment." On that statement, I am not with you. I want to know the maximum power output of the Ghost at a given regulator pressure with a given barrel and projectile, using the hammer springs that BRK is supplying with guns.
We also have in the Ghost a novel type of valve that doesn't seem to respond to adjustments as a typical PCP would. It is much easier to open than traditional valves, ie, with a traditional pcp valve, the higher the regulator pressure is, the harder you've got to smack that valve to get it to open b/c it has more pressure keeping it shut. And that is not 100% the case with the valve in the Ghost, probably because the valve doesn't have pressurized plenum air keeping it shut. So using phrases like "tuning on the knee" (that we've picked up from reading on the forums about how others have "tuned" guns with traditional valves) and trying to apply that thought process to the Ghost's valve is like trying to describe how the color blue sounds. For example, usually a PCP will put our more fpe as the regulator pressure increases, as long as you keep smacking that valve harder, at least up to the point that porting becomes the reducing factor. That has not proven to be the case with the Ghost, at least within the parameters of dropping a 23 inch .22 barrel in a chassis that was previously a .177 Carbine. I do not know if similar effects will be seen in other scenarios, as I can only report on what I'm experiencing.
Everybody's favorite and fabled knee in the PCP world is with the end goal of consistency, and perhaps even getting a couple of bonus shots below reg pressure that are within the desired ES, when everything works out just right. With the Ghost, every string I have ran over the chrono has produced a more than tight enough extreme spread for any and all of my uses for a PCP, with no knee (s) in sight, or even on the mind.
Please take another read through the data shared in the chrono sessions. The rationale for the process is explained in excruciating detail.
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Thank you very much for your reply. I was not aware that the Ghost has a complete different way of operating than other pcp’s In terms of that the reg pressure is of no ( less) influence on the valve opening . This is very interesting. i have been reading some info on the internet re balanced valves and indeed this style of valves look so promising . Quitness, Creep, consistency seems to be positively influenced by a balanced valve. I will follow your postings and from others re BKR Ghost carefully as this gun is very tempting to me.
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I agree that the Ghost's ability to make power, due to that valve being vented to atmosphere, is an exciting feature.
I know that with every other sub 20fpe "field target legal" .177 gun that I've shot, there's no way they would ever produce 48fpe by just switching to a .22 barrel and sightly heavier hammer spring. And supposedly we should be seeing more power in .22 than I am!!!
The best example I can give is when I put a .22 barrel in my .177 USFT. That gun runs at 905-930fps with .177/10.34 (just under 20fpe). With a 24 inch .22 barrel the most fpe I could get was just under 30, and that was with increasing hammer spring preload to max AND adding a lot of hammer weight. Supposedly that platform can get up around 45fpe with .22, but it requires changes to the valve stem and porting. And there's the rub with the Ghost, nothing more than the .22 barrel and a slightly heavier hammer spring are necessary to more than double the fpe.
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Thanks again. I wonder where you would end up with the heavies spring in .22 configuration in case you would preset the hammerspring in such way that position 19 & 20 on the hammerwheel would not give increased speed anymore. I know you are a bit tired of testing over the chrony but could you do that maybe ?
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The hammer tension adjust always creates the same preload at a given setting, given equal spring is being used.
You're asking me to stuff some shims in there or use a heavier hammer spring than BRK OEM? both of which I have no interest in, nor does it serve the purpose of reporting on the Ghost that I am doing here.
To summarize, with the 0.051" wire hammer spring that BRK supplies, the maximum foot pounds from this Carbine .177 when converted to .22 with a 23 inch OEM Ghost barrel is 48.8foot pounds. Which is obtained at about 128-130 on the regulator, with the hammer spring preload at maximum, and the threaded nose of the hammer extended 1/8 of an inch.
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