Tuning any tuning tips for the FX Crown MKII with .25 25.39 grain JSB Exact?

[bd2021]

What should I start the regulator at, for example? What speed would probably work.

I understand that your settings may not work for me, but I am just trying to get a good starting point.

Thanks!

 

[gfmiller58]

BD;

I've got a Crown II Continuum with 380mm and 600mm barrels. (I know it is supposed to be 700mm but it isn't.) As purchased, the gun was wearing the short barrel, the regulator was set at 150 bar, and both adjuster wheels at their maximum settings. That shot the 25.39gr JSB pellets at about 871 fps very accurately. Recently I've been experimenting with the 600mm barrel and found that reducing the regulator to 130 bar increased my velocity to the max possible with the stock hammer and spring. I have two settings with the longer barrel; for paper targets I run the front wheel at MED and the rear wheel at 14 (new power wheel with 1-24 settings, no A, B. C, etc. This is very accurate and launches the 25.39gr JSB pellets at 874 fps. This is the tune I use most often. It is relatively quiet, very accurate and delivers I lot of shots from a single air charge.

For hunting / pesting I run the front adjuster on HIGH and the rear adjuster on 24. That launches the 25.39gr JSB pellets at 1015 fps. This is still very accurate but cuts my shots per fill almost in half. It's louder, but the trajectory is pretty flat out to 50 yards.

Hope that helps. Have fun.

George

 

[bd2021]

Thanks @gfmiller58. Do you know if I can take the bottle off without discharging?

Testing out the FX Radar I just got, I'm at 115 bar on the regulated, High on the front dial, and max on the back, I got:

Shot count: 5
Low: 893
Hi: 909
Avg: 903
STD Dev: 5.9
Spread: 16.0

3/17/22 7:39:26 PM,907
3/17/22 7:39:36 PM,893
3/17/22 7:39:43 PM,907
3/17/22 7:39:49 PM,909
3/17/22 7:40:08 PM,900

I haven't tried to site it in too much yet as I think I need to remount the scope and possibly get better scope mounts (though the ones on the gun are rather expensive). The current mounts are IPS-30.

 

[gfmiller58]

Sorry, I've never attempted to remove the bottle. Can't tell you if it has to be discharged first.

 

[Long_Gun_Dallas]

The bottle is meant to be removed. But take care. I'd advise removing it at a lower pressure, and putting some silicone grease on the oring (very small amount). The oring can tear under a lot of pressure. Also, make sure the joiner or adapter doesnt thread out of the block when taking the bottle off. I've seen mine try to do this, too.

900 fps is a happy place typically. But I like running ~135bar on my regulator. Going low tends to make the gun louder, and uses more air volume per shot. For a harmonically happy gun, it's better to have more pressure, too, as the valve action will be shorter and snappier. 

 

[jml281]

I realize you asked about a starting point for the 25.39 grain JSB Exacts. I have a .25 MkII Crown with the 600mm barrel in a Saber Tactical chassis. It is tuned for shooting the 34 grain JSB and FX heavies at 910. My regulator is set at 150 bar, hammer spring is pretty much maxed out. 

I can shoot the 25.39 grain JSBs at 890 simply by turning down the power wheel to 12.

If there's no wind and I'm not shooting past 50 yards, I use the 25.39 grain pellets.

If there's some wind, I'll shoot the 34 grain pellets.

If I want to shoot 100 yards or greater, I shoot JSB Knock Outs. The interesting thing with the Knock Outs is that the point-of-aim and point-of-impact is the same as the FX Heavy pellets.

I forgot to mention, I also have the harmonic tuner installed and I'm using the FX/DonnyFL moderator.

 

[bzizzi373]

Yes, I have tested various settings of my Crown MK2 .25 using 25.4 JSB's with 600 barrel and noticed that the gun is more accurate with higher regulator settings, Right now my reg is set @ 145 BAR and I back off power wheel to achieve the velocity I want, right now gun is set right around 935 FPS, however gun remains accurate at 970 FPS with the click of the wheel. My MK2 will top out close to 1000 FPS but accuracy diminishes.

 

[MEC17670]

When I got my Crown mk 2 in .25, I found the internal hammer didn't start moving till 8 on the external hammer adjustment. Reg set at 115 and transfer port set at max . I could only achieve 870 with the 25.39 exact. I adjusted the internal to start moving @1.5 external guage. Found that at max external 24 with 140 reg pressure the velocity dropped however when I readjusted the reg to 110 , the pellets flew 904 905 range. 

Seems to me that the lower reg pressure with high hammer striking force allowed the valve to remain open longer.

At 905 the pellets were 1on1 at 57 yards.

I would like to be able to shoot slugs also so do I need to adjust internal hammer to more at 1 external dial to allow for a higher reg pressure?

Then turn down power wheel for pellets?

Thanks,

Mike

 

[Sanctify7]

BD;

I've got a Crown II Continuum with 380mm and 600mm barrels. (I know it is supposed to be 700mm but it isn't.) As purchased, the gun was wearing the short barrel, the regulator was set at 150 bar, and both adjuster wheels at their maximum settings. That shot the 25.39gr JSB pellets at about 871 fps very accurately. Recently I've been experimenting with the 600mm barrel and found that reducing the regulator to 130 bar increased my velocity to the max possible with the stock hammer and spring. I have two settings with the longer barrel; for paper targets I run the front wheel at MED and the rear wheel at 14 (new power wheel with 1-24 settings, no A, B. C, etc. This is very accurate and launches the 25.39gr JSB pellets at 874 fps. This is the tune I use most often. It is relatively quiet, very accurate and delivers I lot of shots from a single air charge.

For hunting / pesting I run the front adjuster on HIGH and the rear adjuster on 24. That launches the 25.39gr JSB pellets at 1015 fps. This is still very accurate but cuts my shots per fill almost in half. It's louder, but the trajectory is pretty flat out to 50 yards.

Hope that helps. Have fun.

George

Hi, gf58. If BD21 doesn't mind, I'd like to get in this thread directly to you. I am currently shooting a Crown MK II with the 380mm barrel. I bought it off an AGN member, who barely used it. The hammer is set on 23 or 24 (new style) and TP on High. I am wondering if this is exactly as yours was and if my 25.39s are going at about 871 fps as yours are. Perhaps FX sends them out like this?
Here's another question: Is the 600mm barrel at 1015 fps louder than the 380mm barrel at 871 fps? I have the typical 700mm barrel but have not used it yet. Thanks. S7

 

[Sanctify7]

When I got my Crown mk 2 in .25, I found the internal hammer didn't start moving till 8 on the external hammer adjustment. Reg set at 115 and transfer port set at max . I could only achieve 870 with the 25.39 exact. I adjusted the internal to start moving @1.5 external guage. Found that at max external 24 with 140 reg pressure the velocity dropped however when I readjusted the reg to 110 , the pellets flew 904 905 range.

Seems to me that the lower reg pressure with high hammer striking force allowed the valve to remain open longer.

At 905 the pellets were 1on1 at 57 yards.

I would like to be able to shoot slugs also so do I need to adjust internal hammer to more at 1 external dial to allow for a higher reg pressure?

Then turn down power wheel for pellets?

Thanks,

Mike

"At 905 the pellets were 1on1 at 57 yards." I like it. S7

 

[gfmiller58]

S7;
My Crown came set up as follows: Transfer port: High, Hammer Wheel: Max and Regulator: 140 Bar. With the 380mm barrel it shot the JSB 25.39 gr pellets at 874 fps with extreme accuracy and consistency. My experience has been that the higher the velocity the louder the sound. Once I get over 1000 fps the sound really increases!

 

[Sanctify7]

S7;
My Crown came set up as follows: Transfer port: High, Hammer Wheel: Max and Regulator: 140 Bar. With the 380mm barrel it shot the JSB 25.39 gr pellets at 874 fps with extreme accuracy and consistency. My experience has been that the higher the velocity the louder the sound. Once I get over 1000 fps the sound really increases!

Thanks, GF58. My regulator is at 150, and everything else is factory maxed, I believe. I wonder how the extra 10 BAR on the reg is affecting things. I am not sure mine is at "extreme accuracy and consistency." I think it is, but I need a bit more time as I just zeroed it in. Yes, I use the JSB 25.39 gr. I need to slap on the FX chronograph and see what's what. I would like to lower the regulator to 130 or 140, but I want to see how the 150 is doing first. Copy: more speed, more noise. What do you have on it for a moderator? S7

 

[gfmiller58]

Thanks, GF58. My regulator is at 150, and everything else is factory maxed, I believe. I wonder how the extra 10 BAR on the reg is affecting things. I am not sure mine is at "extreme accuracy and consistency." I think it is, but I need a bit more time as I just zeroed it in. Yes, I use the JSB 25.39 gr. I need to slap on the FX chronograph and see what's what. I would like to lower the regulator to 130 or 140, but I want to see how the 150 is doing first. Copy: more speed, more noise. What do you have on it for a moderator? S7

S7;
I have an FX/Donny FL moderator on my Crown. A chronograph is extremely helpful for tuning and adjusting airguns. Without one I wouldn't have discovered that increasing the regulator (above the original setting of 140 Bar) actually decreased the muzzle velocity. For my Crown maximum velocity was at 135 Bar.
What I learned with the Crown is the listed power levels can only be achieved with the slug kit. To utilize higher regulator pressures, and get the maximum advertised power, requires increased hammer weight and/or hammer spring.

 

[Sanctify7]

S7;
I have an FX/Donny FL moderator on my Crown. A chronograph is extremely helpful for tuning and adjusting airguns. Without one I wouldn't have discovered that increasing the regulator (above the original setting of 140 Bar) actually decreased the muzzle velocity. For my Crown maximum velocity was at 135 Bar.
What I learned with the Crown is the listed power levels can only be achieved with the slug kit. To utilize higher regulator pressures, and get the maximum advertised power, requires increased hammer weight and/or hammer spring.

Greetings, GF58.
I follow most of this. Two things have me thinking. One, I understand that reg pressure and the hammer are both parts of this power/balance equation. Are you here referring to the internal hammer adjustment for gaining more power? Two, you are making me wonder if the 150 BAR reg setting that came with my Crown via an AGN member was set there by him or the factory, now that you are saying yours came in at 140. So, if I got you, you lowered it to 135 and got more velocity? Is it presently at 140 or 135 BAR? I mean, if my situation is the same as yours, give or take a wee bit, I would want to drop the reg to 135 or 140. It saves air, too. My problem is that the guy I bought the gun off is a really nice sort, but he is older school (so am I) and not great with texting. I would ask him, in other words, if I could. And, God willing, I will be slapping my FX Chronograph on the gun as soon as I can. I am dying to know what my speed is.
Thanks. S7

 

[gfmiller58]

Greetings, GF58.
I follow most of this. Two things have me thinking. One, I understand that reg pressure and the hammer are both parts of this power/balance equation. Are you here referring to the internal hammer adjustment for gaining more power? Two, you are making me wonder if the 150 BAR reg setting that came with my Crown via an AGN member was set there by him or the factory, now that you are saying yours came in at 140. So, if I got you, you lowered it to 135 and got more velocity? Is it presently at 140 or 135 BAR? I mean, if my situation is the same as yours, give or take a wee bit, I would want to drop the reg to 135 or 140. It saves air, too. My problem is that the guy I bought the gun off is a really nice sort, but he is older school (so am I) and not great with texting. I would ask him, in other words, if I could. And, God willing, I will be slapping my FX Chronograph on the gun as soon as I can. I am dying to know what my speed is.
Thanks. S7

S7;
I was not referring to the set screw adjustment on the hammer wheel, but rather a new hammer spring and or hammer weight. I started down the rabbit hole of chasing more velocity, and installed a slug power kit. I never could get slugs to shoot as well as pellets, and decided the effort was a waste. I'm reverting back to 25.4 gr pellets out of the short barrel. I still have the slug power kit installed, but will probably remove it since it is not as consistent as the original set up.
You really need a chronograph to tune these things. There are too many things that effect the velocity and consistency. I started out with the regulator at 140 bar and both wheels maxed out. I installed a pin probe and got about a 20 fps increase. I then increased the regulator pressure to 150 bar expecting velocity to increase, but instead it decreased. So I began testing and found that my gun achieved the maximum velocity with the regulator set at 135 bar.

 

[Sanctify7]

S7;
I was not referring to the set screw adjustment on the hammer wheel, but rather a new hammer spring and or hammer weight. I started down the rabbit hole of chasing more velocity, and installed a slug power kit. I never could get slugs to shoot as well as pellets, and decided the effort was a waste. I'm reverting back to 25.4 gr pellets out of the short barrel. I still have the slug power kit installed, but will probably remove it since it is not as consistent as the original set up.
You really need a chronograph to tune these things. There are too many things that effect the velocity and consistency. I started out with the regulator at 140 bar and both wheels maxed out. I installed a pin probe and got about a 20 fps increase. I then increased the regulator pressure to 150 bar expecting velocity to increase, but instead it decreased. So I began testing and found that my gun achieved the maximum velocity with the regulator set at 135 bar.

Got it all, GF58. And it is logged. If I end up dropping the reg to 135 or so with the short barrel (which I presently like), I would imagine getting about five to ten more shots. Yes? Thanks. S7

 

[Sanctify7]

The bottle is meant to be removed. But take care. I'd advise removing it at a lower pressure, and putting some silicone grease on the oring (very small amount). The oring can tear under a lot of pressure. Also, make sure the joiner or adapter doesnt thread out of the block when taking the bottle off. I've seen mine try to do this, too.

900 fps is a happy place typically. But I like running ~135bar on my regulator. Going low tends to make the gun louder, and uses more air volume per shot. For a harmonically happy gun, it's better to have more pressure, too, as the valve action will be shorter and snappier.

I just saw this, LGD. What you are saying ("Going low tends to make the gun louder. . . ." ) seems to fly in the face of what I have seen on YouTube by accomplished people, such as Steve from AEAC Vlog. I understand that harmonics involve the right balance between hammer and reg pressure. Please assist if you will. Thank you. S7

 

[Sanctify7]

I realize you asked about a starting point for the 25.39 grain JSB Exacts. I have a .25 MkII Crown with the 600mm barrel in a Saber Tactical chassis. It is tuned for shooting the 34 grain JSB and FX heavies at 910. My regulator is set at 150 bar, hammer spring is pretty much maxed out.

I can shoot the 25.39 grain JSBs at 890 simply by turning down the power wheel to 12.

If there's no wind and I'm not shooting past 50 yards, I use the 25.39 grain pellets.

If there's some wind, I'll shoot the 34 grain pellets.

If I want to shoot 100 yards or greater, I shoot JSB Knock Outs. The interesting thing with the Knock Outs is that the point-of-aim and point-of-impact is the same as the FX Heavy pellets.

I forgot to mention, I also have the harmonic tuner installed and I'm using the FX/DonnyFL moderator.

JML281, the 34 grain pellets at 910 = about 62 FPE. That's a fairly stout load.
I have one question: When you turn the PW down to 12, how are the sound and accuracy affected, if you don't mind saying? Thanks. S7

 

[Long_Gun_Dallas]

I just saw this, LGD. What you are saying ("Going low tends to make the gun louder. . . ." ) seems to fly in the face of what I have seen on YouTube by accomplished people, such as Steve from AEAC Vlog. I understand that harmonics involve the right balance between hammer and reg pressure. Please assist if you will. Thank you. S7

Yes, it will be dependant on a number of variables, but I can usually make a gun quieter under higher pressure operation (for the same power level) of course this won't always be true. But absolutely can be.

 

[Long_Gun_Dallas]

Harmonics are also abundantly complex. But as stated, an ideal tune for me will start by finding where the gun starts to fall off of power. Using max hammer, and just operating on pressure adjustment. This will give you three things. It will give you a pressure region where power is still increasing, stops increasing, and starts decreasing (at even higher pressures). For my ported gen 3 (Mk1) 22cal with 380mm barrel, this is somewhere around 140bar that it tops out. Either side, it falls off. In my mind there are two acceptable methods of tuning here. You want the gun set on either side of the power curve. Either where it is still increasing in power or where it is decreasing in power. I chose the lower side (135 bar) so that I hopefully get a bit higher shot count and also don't need a higher operating pressure. From here you can tune the hammer further so see what kind of power curve the gun produces with varying hammer pressures, and then adjust it to a similar region (below the peak power). In theory this should give short, snappy valve dwell, and improved harmonics as well as excellent es. You can still fine tune es and accuracy from here. But harmonics are affected by everything. So, you just have to find what your gun likes best. For instance, long barrels tend to do best with no moderator at all.