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Brocock sniper xr 25cal tuning

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drsquall

drsquall

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Jul 22, 2022
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Hello,
I just got this I got it from the classifieds. I am trying to 50fpe for our local eft matches. I have been able to get 45 with the 33.95 and about 42fpe with the 25.39s. The reg is at 170 and haven't taken it out of the stock to see where the hammer spring is at yet. It likes both equally well accuracy wise maybe the 25s a little better. We can only shoot pellets in eft here. The power wheel is at full

Here's the chrono info
What should I try next? I am new to tuning so I appreciate all the help

Thanks
Jon

View attachment brocock-25-full-power.pdf

View attachment brocock-25-full-power.pdf
 
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drsquall said:
Hello,
I just got this I got it from the classifieds. I am trying to 50fpe for our local eft matches. I have been able to get 45 with the 33.95 and about 42fpe with the 25.39s. The reg is at 170 and haven't taken it out of the stock to see where the hammer spring is at yet. It likes both equally well accuracy wise maybe the 25s a little better. We can only shot pellets in eft here. The power wheel is at full

Here's the chrono info
What should I try next? I am new to tuning so I appreciate all the help

Thanks
Jon

View attachment 362884

View attachment 362894
Click to expand...
I thought about putting the reg to 150 and start adjusting the hammer spring to see how it does.
 
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bigmike said:
If it is the Sniper and not the Magnum you are about maxed out. I had the same gun but never set the reg above 160 and could only get 46fpe out of the gun. I believe 170 reg pressure is beyond what Brocock recommends.
Click to expand...
1686275694699.png
 
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If it were me, I'd set the reg at 140bar and back out the hammer spring a few turns. Shoot a few and keep raising the hammer spring tension until you max out on velocity. If this velocity is not 10% more than what you're looking for, then raise reg pressure to 145bar and start over. Keep going until you get a max velocity that is roughly 10% higher than what you're looking for and then reduce hammer spring tension to get at least a 5% (5-10%) reduction in velocity and you're there.
For whatever reason, those Brocock rifles are some of the most consistent pcp rifles I've ever shot. I can't imagine what they do differently, but it is no trick to stay below 10fps over a full shot string on my HR. I also played with an XR magnum and it too was amazing. I don't think there's much new under the sun, but whatever they do on those guns they do it right! I wish they would put an actual two stage match trigger on them, and I'd sell every other gun I own, no kidding.
 
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@drsquall I shoot a Bantam Sniper HR in .25 Reg is set around 145 bar. I’d have to do some searching for the hammer spring measurement.
C8671BD9-2B95-451E-81AB-4E5C811A6902.jpeg

I think you’ve received some sound advice about coordinating balanced adjustments between the reg and hammer spring. I haven’t pushed mine to its power limits. It does what I need it to do the way I have it set. I also do not recall what the differences are between the HR and XR. I discussed it with a member recently but I can’t recall the details. I’m not so sure that sharing my experiences would be of much use to you. There’s a pretty good thread on the Sniper HR that I have bookmarked if you’re interested. I think other members will benefit from you documenting details of your tuning discoveries in this thread. Thanks for sharing.
 
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I am going to try reg at 140 and start there. Do you get reg creep? I feel I get at times maybe 5 bar increase. Also, I take the gun out of the stock to tune it so it's easier to adjust hammer spring. All this is new to me so I got another question- sometimes when shooting it without the stock I hear a little noise like the reg filling up again. It's not happening all the time. I haven't figured if it's when the reg is at a certain setting or the hammer spring tension greater less?

This one chrono with the 34

View attachment brocock-25-150-reg-4-threads-in-on-hammer-34-fx.pdf
 
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@drsquall I have experienced reg creep in my Bantam Sniper HR. I sent the rifle in to AOA (where I purchased it) to be serviced and it worked fine for a month or two. The issue seemed to arise because I was filling the reservoir to 225-250 bar. My final remedy was to purchase and install a new Huma Air regulator for my particular gun. I also stopped filling my reservoir beyond 215 bar. No issues with reg creep since.

I wasn’t shooting without the stock when I tuned my rifle, but it sounds like you may be hearing the sound of air refilling the plenum. I have other guns that do this. Seems normal to me.
 
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Ezana4CE said:
@drsquall I have experienced reg creep in my Bantam Sniper HR. I sent the rifle in to AOA (where I purchased it) to be serviced and it worked fine for a month or two. The issue seemed to arise because I was filling the reservoir to 225-250 bar. My final remedy was to purchase and install a new Huma Air regulator for my particular gun. I also stopped filling my reservoir beyond 215 bar. No issues with reg creep since.

I wasn’t shooting without the stock when I tuned my rifle, but it sounds like you may be hearing the sound of air refilling the plenum. I have other guns that do this. Seems normal to me.
Click to expand...
That could be it I am filling it to about 240bar. I will lower the fill pressure and see what it does
 
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drsquall said:
That could be it I am filling it to about 240bar. I will lower the fill pressure and see what it does
Click to expand...
@drsquall Shouldn’t hurt to give it a go. In my experience once the reg starts creeping, it can continue, at time intermittently. Until you get your reg rebuilt or a new one, I suggest filling your gun’s reservoir slowly and not filling it beyond 215 bar. See if it makes a difference. To be clear, when I say “creep,” I mean that my regulator’s set pressure would increase when I filled the rifle. If I remember correctly it was set at 140-145 bar and would move up to around 155 bar when filling. I’d usually notice my reg gauge starting to move or “creep” around 220-225 bar. My first few shots would be hot amd they’d calm down as the reservoir pressure was shot down. Then I’d get within the regilator’s set range and I’d have pretty consistent shots until I shot the gun’s reservoir pressure below the regulator’s set point (falling off the reg). At that point the regulator’s gauge set point would drop. When this happens, it’s time to stop shooting. Ideally one would want to refill their gun before falling off of the regulator.
 
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Ezana4CE said:
@drsquall Shouldn’t hurt to give it a go. In my experience once the reg starts creeping, it can continue, at time intermittently. Until you get your reg rebuilt or a new one, I suggest filling your gun’s reservoir slowly and not filling it beyond 215 bar. See if it makes a difference. To be clear, when I say “creep,” I mean that my regulator’s set pressure would increase when I filled the rifle. If I remember correctly it was set at 140-145 bar and would move up to around 155 bar when filling. I’d usually notice my reg gauge starting to move or “creep” around 220-225 bar. My first few shots would be hot amd they’d calm down as the reservoir pressure was shot down. Then I’d get within the regilator’s set range and I’d have pretty consistent shots until I shot the gun’s reservoir pressure below the regulator’s set point (falling off the reg). At that point the regulator’s gauge set point would drop. When this happens, it’s time to stop shooting. Ideally one would want to refill their gun before falling off of the regulator.
Click to expand...
That's what is doing I'm pretty sure.

Thanks
Jon
 
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