Brocock/BRK brk ghost velocity climb

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hey guys. my ghost shot about 2500 slugs so far.it was tuned to shoot 13.43 KOs at 965fps and NSA 15 at 930. regulator at 155 and hammer wheel at 16. today while i was shooting the noice changed and it started shooting 10cm above zero. it climbed at 990fps and the hammer noice is a lot more Noticeable. now to be able to shoot 960 i had to put the hammerwheel at number 6 but my groups opened significantly,reg pressure is still at 155 bar. obviously the riffle will go back to the shop for inspection, but did it happened to anybody else? thanks in advance

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Doesn't that just mean that your regulator is set too high, which you have to compensate for with more hammer spring, which once you drop below the reg setting will release more air and your speed will shoot up? This just happened on one of my guns. Or am I missing something here? I don't own a Ghost but I thought that they are a classical mechanical design. I would just drop the reg pressure, adjust hs for speed and try again.
 
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PumaCarl said:
Doesn't that just mean that your regulator is set too high, which you have to compensate for with more hammer spring, which once you drop below the reg setting will release more air and your speed will shoot up? This just happened on one of my guns. Or am I missing something here? I don't own a Ghost but I thought that they are a classical mechanical design. I would just drop the reg pressure, adjust hs for speed and try again.
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the speed was maxing at powerwheel number 10 before at 145 bar. at 155 it is maxing at number 16. so for another 4 clicks the speed was not rising.
 
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trompis said:
the speed was maxing at powerwheel number 10 before at 145 bar. at 155 it is maxing at number 16. so for another 4 clicks the speed was not rising.
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Correct, because of the added pressure on the valve, it takes more force to open it. That extra force needed to crack that valve open will still be there, along with 10 extra bar of pressure when you come off the reg and your speed will shoot up. You need to decrease your reg pressure and set your hammerspring so that when you come off the reg your speed only jumps up slightly. This is what is called tuning to the knee. It is what tuning is all about. Everything has to be done in balance. If you don't want that balance/efficiency, you just want that speed or power that is fine, just know that you can't shoot accurately once you go off regulator. You'll just have less available good shots.
 
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PumaCarl said:
Correct, because of the added pressure on the valve, it takes more force to open it. That extra force needed to crack that valve open will still be there, along with 10 extra bar of pressure when you come off the reg and your speed will shoot up. You need to decrease your reg pressure and set your hammerspring so that when you come off the reg your speed only jumps up slightly. This is what is called tuning to the knee. It is what tuning is all about. Everything has to be done in balance.
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to be specific again. it was shooting great for 2 weeks at that pressure and hammer tension and this tune . and for most of my session yesterday. all of a sudden the sound of the riffle changed and the speed went up. and forgot to mention the cocking lever became harder to pull
 
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If the cocking lever became harder to pull it's because you increased your hammer spring tension. If this problem is happening at the beginning of your string and not coming off the regulator, you could be experiencing partial valve lock. You have so much pressure on the valve, at first, that the valve is less effective at cracking open until the pressure drops a little. Again, I think the problem has to do with starting with too high of settings. Back way off and work up, either way.
 
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PumaCarl said:
Correct, because of the added pressure on the valve, it takes more force to open it. That extra force needed to crack that valve open will still be there, along with 10 extra bar of pressure when you come off the reg and your speed will shoot up. You need to decrease your reg pressure and set your hammerspring so that when you come off the reg your speed only jumps up slightly. This is what is called tuning to the knee. It is what tuning is all about. Everything has to be done in balance. If you don't want that balance/efficiency, you just want that speed or power that is fine, just know that you can't shoot accurately once you go off regulator. You'll just have less available good shots.
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with the hp hammerspring on the ghost at factory pressures it maxes at powerwheel number 10 (it has 20) so lowering the regulator i will have to swap a spring for a softer one otherwise i will bent a valve . the problem is that all of a sudden while the gun was shooting great for days, it started sounding different .
 
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pesty3782 said:
Check for a pellet that fell Back into the hammer channel…It has happened before….Super easy fix, take the rear of the rifle apart. The last one I fixed for a friend had 2 smashed pellets in the hammer channel, and flakes in the sear cassette.

Tony P
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hi. i just removed the hammer everything is clean in there. wasn’t it supposed to have a spring guide inside the hammer? the spring litteraly swims in there, the hole in the hammer is too big
 
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trompis said:
to be specific again. it was shooting great for 2 weeks at that pressure and hammer tension and this tune . and for most of my session yesterday. all of a sudden the sound of the riffle changed and the speed went up. and forgot to mention the cocking lever became harder to pull
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Some pellet debris may have fallen back into your action - see Sub12 YouTube
 
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trompis said:
hi. i just removed the hammer everything is clean in there. wasn’t it supposed to have a spring guide inside the hammer? the spring litteraly swims in there, the hole in the hammer is too big
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You need to retighten the hammer spring adjustment up against the spring - do this with power wheel on min and breech closed - requires a little disassembly 2 mm / 2.5mm / 3mm Allen required
 
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cavedweller said:
You need to retighten the hammer spring adjustment up against the spring - do this with power wheel on min and breech closed - requires a little disassembly 2 mm / 2.5mm / 3mm Allen required
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the adjustment screw on the hammer was in the very early models. the new ones even though threaded their is no more adjustment other than turning the power wheel. i dissasembled the hammer everything is clean . the hammersping is the 52mm HP1.
 
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trompis said:
the adjustment screw on the hammer was in the very early models. the new ones even though threaded their is no more adjustment other than turning the power wheel. i dissasembled the hammer everything is clean . the hammersping is the 52mm HP1.
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ohhh wow - that's not only interesting it is great info! So if i understand you correctly the two screws that held the hammer up against the spring have been eliminated? @trompis
 
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