Tuning New Chrony, Opinions on #'s and Prod Regs

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LeadandAirFun

LeadandAirFun

Member
Oct 23, 2021
68
9
North Carolina, United States
I followed the wisdom form what Ive learned so far on this site and got a Caldwell chronograph before attempting any tuning on the Prod. This chrony has to be shot through at just the right place I found or an error code comes up. This is the second one (the deluxe with lighted sunshades and tripod) since I couldn't get a reading in any light condition with the first. It's not the best quality but I guess I got what I paid for. Anyhow I can see in numbers the FPS bell curve that was talked about in some earlier posts. I'd like to flatten that to get around 600. I was thinking about getting that Huma air regulator but wanted to get the thoughts and opinions from you gentlemen first. Also Is there an indexed hammer adjustment knob available? I'd like to have the convenience of adjustment without an allen key and be able to see what the adjustment is. Here are the numbers
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Lead,

Not long ago I bought a E9800-X Chronograph on eBay for around $60. It's a basic, "shoot-thru," that doesn't calculate nor save data at shut-off. I'm not a long-range shooter and prefer pellets with factory gun settings, but it really came in handy, along with a few helpful members, cleaning up the accuracy on my Uragan and Taipan Veteran .25s with JSB 33.95 grains. Lacking calculations, I Googled "standard deviations" and found a formula that allows you to enter numbers, separated by a comma, that provides Median FPS, Extreme Spread and Standard Deviation. Taking that info to another site I get Foot Pounds of Energy (FPE.) I realize a few hundred would provide a chronograph system to handle all the calculations but, for now, I economize and put the limited hobby dollars towards future gun purchases. WM
 
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Since everyone seems to want to talk about their chronographs, I’ll try to help you with your gun. I’ve had a Prod for quite some time. Shot it stock for a while, then with a SS valve, and finally with a reg. The only thing I can’t help you with is your choice of pellet weight versus mine. I took a look at the platform, it’s components and decided a 14.3gr pellet was probably what would give me the best bang for my buck so that’s what I stuck with. When you go heavier, you have to lean on the gun. Yeah, you can hot rod a Prod but I try to follow the rules of diminishing returns. As you can see from your shot string, things start to look better at shot 20 to 52. So you now know your operating range. The Prod is not a long bomber so you don’t need a real tight extreme spread. Your current settings, maybe a quarter less turn on the HS are probably going put you right where you want to be with a 14.3gr pellet. Now concerning a reg, it’s not a slap in a reg then live happily ever after affair. You will need to open all ports. Transfer, barrel and valve to 3.5mm. Then build a SSG. I’ve had a SSG on my gun within a month of owning it. Hammer bounce sucks and once you have a reg in and are operating at a lower pressure, hammer bounce becomes even more evident. So to sum it up, you should probably switch to a lighter pellet. Save yourself the grief of starting out asking the gun for more than its platform can happily deliver. It’s not a Edgun Leshiy, it’s a Benjamin that costs a whole lot less Benjamin’s.
 
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@LeadAndAirFun I think @VetMX keyed in on an essential factor, the platform itself. With that said he's provided an ideal pellet weight suggestion, that is if you're set on keeping your Prod stock. If not, then considering watching this video to see what different sized transfer ports can do.







https://www.youtube.com/watch?v=qoJnSwFiX8w







Up the TP size (either alter yours, make a new one, or pay a machinist to make one (or buy one already made for the gun), install it, and adjust the hammer spring tension (HST) and hammer throw. Here's a video on simple Prod tuning.







https://www.youtube.com/watch?v=IjtnIAiVxKc









I don't know anything about an external HST adjuster for these. Also try shooting a decent variety of brands and weights of pellets (if you haven't already) before changing anything in order to gauge the gun's capability as is. I have no input on regs. As for the numbers, 610-670 for a variety of 14.3 grain pellets (or there about) is good within 30-35 yards.

As for your chronograph, does it give you error messages in direct sunlight? Like @Scotty1 I have a ProChrono DLX. I get "error" messages in cloudy weather, in the shade, and sometimes if I shoot the string too quickly. I've never used the chronograph you're using, but perhaps these are factors to consider with that model as well.



What exactly is it that you'd like to do with your gun shooting 17-18 grain pellets?
 
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Vetmx thanks for the regulator insight. I'm wondering now if it's even worth it, not a cheap part after all. What is a SSG? I'll try the 14.3 grain and back the hammer off then see if it gets up into the 600s. I've only ran the 17 grain pellets through it so far. I'll be interested to see how much difference in FPS I'll get with lighter pellets. Ezana, Is 17gr heavy for this gun and tune? Typically all I do with it is plink in the garage (25') or punch paper in the the side yard (30yds)
 
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Vetmx thanks for the regulator insight. I'm wondering now if it's even worth it, not a cheap part after all. What is a SSG? I'll try the 14.3 grain and back the hammer off then see if it gets up into the 600s. I've only ran the 17 grain pellets through it so far. I'll be interested to see how much difference in FPS I'll get with lighter pellets. Ezana, Is 17gr heavy for this gun and tune? Typically all I do with it is plink in the garage (25') or punch paper in the the side yard (30yds)
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@LeadandAirFun I can't say. I can only determine that from shooting the tune. Even then, it's better for me when I shoot it across a chronograph. I'm just getting into this gun as well, but what I'm sharing with you is information that I have used and personal experience. I've shot different weights and brands and was surprised that Crosman Hollow Point Premiers 14.3 grain grouped best. Especially after I spent about $150 on an assortment of other pellets that I tested first. I've shot the Prod out to 50 yards, but like how it performs best within 30. I'm trying to get more comfortable stretching it out to 35 yards. Within 30 the animal is taking lead. I'll probably take her out hunting later today. If I can remember at a later time I'll dig up some targets, check my notes on the heavier pellets, and get back to you with more details. I'm thinking that within 20-25 yards you may be able to shoot the 17-18 grainers, just expect to be shooting at lower velocities which may perform below optimal levels for that pellet weight unless you make the necessary adjustments to increase velocity. After checking some of my data, I also shot 15.8 - 16 grain pellets pretty well within the 655-570 fps range, peaked at 655 fps . With the 14.3 grainers I was just breaking 680 fps at peak velocity to give you an idea of the difference in velocity at about a 1.5 grain difference. If you're interested I've located pre-made transfer ports (and other aftermarket parts) similar to the ones in the video I linked in my previous post. I also found aftermarket springs if you don't know how to order the correct springs from a manufacturer.

Earlier in the thread you asked about an indexed hammer adjustment dial. I came across this speed dial on AOA's site this morning. They say it's to adjust psi. I'm not quite sure what this thing does. It's over priced if you ask me. https://www.airgunsofarizona.com/parts/custom-speed-dial/#tab-1 Also, I read a thread on the GTA where @BigRagu and @Motorhead commented on this contraption. Both are active members here, so you may want to ask them about it if you're really intent upon installing one. Here's a link to the thread https://www.gatewaytoairguns.org/GTA/index.php?topic=146600.0 @Motorhead called the device a gimick.
 
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I really appreciate the information and links Ezana! I'll give those lighter pellets a shot and try a some incremental adjustments on the HT and HS and see what I can get out of it stock before I start modding. Think I'll stay away from the adjustment knob after reading that thread. I bought this gun from a fellow member who told me that PCP's are super addicting, guy wasn't kidding :)
 
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Vetmx thanks for the regulator insight. I'm wondering now if it's even worth it, not a cheap part after all. What is a SSG? I'll try the 14.3 grain and back the hammer off then see if it gets up into the 600s. I've only ran the 17 grain pellets through it so far. I'll be interested to see how much difference in FPS I'll get with lighter pellets. Ezana, Is 17gr heavy for this gun and tune? Typically all I do with it is plink in the garage (25') or punch paper in the the side yard (30yds)
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A SSG is a spring stopping guide. When you pull the trigger, it stops your spring and your hammer is launched on its own down the tube to smack the valve. When the hammer rebounds off the valve it comes back and hits the preloaded spring in the SSG and stops. Without a SSG, when the hammer rebounds off the valve, it starts to compress your hammer spring again and gets sent right into the valve. So every time you pull the trigger you are double or in some cases triple tapping the valve. You want a gun to go snap when you pull the trigger, not sound like a beer fart. But if you don’t have the means to make a SSG, it’s not the end of the world. Plenty of blubbery sounding guns shoot fantastic. And with the short barreled Prod, you’re relatively safe. They are just wasting air. When it comes to trying big regulated gun size transfer ports on a unregulated gun, you are venturing into a tuning rabbit hole. You can’t just stick a larger transfer port in the gun without port matching the valve and barrel. And once you remove material, you can’t put it back. If you port the gun bigger and don’t like the new bell curve, you can always choke the gun back down by putting the stock TP back in. But the gun might be a little off. Just a little different than what it was when all the stock ports were in harmony. I use cheap Crosman 14gr pellets for most of my Prod shooting. Yes I get more fliers than with JSB but the Crosmans shoot very well at Prod distances. The first pic is the SSG without the gun cocked. Second pic is the gun cocked.
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Beer fart, good analogy ha ha. I know what you mean about that sound. I'm all for saving air, I don't mind pumping, more shots per fill would be nice though. What tools and materials did it take to make that part? I've always enjoyed metalworking. I don't have a lathe but do have a drillpress, taps, dies and my Son works at Ace (big hardware section). I did some tweeking before I ran out of pellets. Gone are the days when a tin would last a month or more with the 1377 and 2240, this Prod is a hungry gun! With the HS at 6 1/2 and the HT at 3/4 using the same pellets I was able to get an average of 20 FPS more in a 12 shot string. I could feel the difference too.
 
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I use a lathe to build them and I usually use brass. Sometimes your stock spring works but sometimes you have to go up a little on wire thickness. You can really go through some pellets during the tuning process with a PCP. Generally, the more adjustable components a gun has, the more pellets you’ll waste. If the Prod didn’t have a hammer throw adjustment, you wouldn’t have to waste pellets testing those settings. I completely eliminated the hammer throw thing with my gun shortly after owning it. With a SSG, the hammer throw thing just isn’t necessary.
 
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I'm finding that out about waste for sure! I bought the Crosman 14.3gr premier hollowpoints at wallyworld today, they peaked at 637 fps. Higher numbers with the lighter grain definitely. It is taking a lot of pellets like you said, especially with a fussy chronograph, but I am getting the feel for the valve and spring. Buying a benchtop lathe has gone from a want to a need now. Many other projects could have used one. Is the B Staley o ring mod worth exploring to deaden the hammer bounce?
 
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I never packed a bunch of orings down inside a gun to control hammer bounce or control valve lift. It’s a shade tree way of trying to fix an issue but it apparently works. I prefer to fix an issue with a permanent reliable fix. B Staley was obviously a guy without a lathe. Creative guys do build SSG’s without a lathe. I’ve seen it and they turned out pretty nice. The ones I make for my guns are probably a little more complex than they need to be. You’ll know your on a good tune with those 14.3’s when you can fill to 2,700psi and get 3 mags around 600fps. That’s when you call it a day and start to enjoy the gun. Shooting over a chronograph isn’t a sport unless you own a FX. But it becomes an addiction for some guys.
 
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I never packed a bunch of orings down inside a gun to control hammer bounce or control valve lift. It’s a shade tree way of trying to fix an issue but it apparently works. I prefer to fix an issue with a permanent reliable fix. B Staley was obviously a guy without a lathe. Creative guys do build SSG’s without a lathe. I’ve seen it and they turned out pretty nice. The ones I make for my guns are probably a little more complex than they need to be. You’ll know your on a good tune with those 14.3’s when you can fill to 2,700psi and get 3 mags around 600fps. That’s when you call it a day and start to enjoy the gun. Shooting over a chronograph isn’t a sport unless you own a FX. But it becomes an addiction for some guys.
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Good to know. Thanks.
 
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Yes, it was the same tune from the Ruger superpoint 17gr. The group is tight, the gun shoots just where I aim it, I dont see the hole untill I move the RDS :) I filled to 2500 and started with an error code (not impressed with the caldwell) then got 620, 5th and 6th shot was at 637 and it dropped erratically from there, the string got to 26 at 578 before dropping off under 1000 psi. Looks like the tune is on then, thanks for that information Vetmx. Are there any links or do you have any pics of what your SSG looks like internally? I'm like you in that I would prefer to have permanent fix rather than relying on rubber. I enjoy getting creative and wrapping my head around mechanical problems. The chrony is just a tool for me, I'd much rather shoot standing off hand. My goal is to get as air efficient as possible.
 
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I don’t have a pic of the one in my Prod. It’s just an educated guess when you make the first one for a gun. Then you might have to mod it or completely make a new one if it doesn’t give you the adjustment range you want. Most chronograph errors are a lighting issue. Even with a light kit I still shoot with a blacked out ceiling over the chronograph downstairs. When dialing a gun in at targets, I have a spot for my chronograph that isn’t very bright. I have a Caldwell with the light kit and the only error I ever got was when I reached through it and it read my hand. Here’s a SSG I just found in my toolbox. I think it was for a Cometa rifle I owned a while back. The smooth part that my hex wrench is pointing at is long on this one because I had plenty of room for a longer spring guide. In my Prod, that part is only 3mm long. It’s enough to center the spring but there isn’t much room in the Prod tube. Hammer travel is short.
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