I was shooting today when I noticed my .25 Bullboss sounded really loud. It holds 9 rounds as you all know and at least 4 of the 9 were at least 3-4 times louder than normal. It has never done this before and has always been 100% solid and dependable. This loudness happened while shooting at 25 and 50 yards and oddly there wasn't any noticeable P.O.I change. Still shooting the same hole. I had 31.4 grain H&N Grizzly slugs in it and they are doing around 880-890 FPS with a chronograph. It's unregulated of course at that speed and the hammer spring tension has been turned up about 3-4 turns. NOTHING else has been done to this gun. With the JSBs 25.39 grain it's shooting at 940 FPS. Has anyone else had this disturbing problem with your shot sounding like a cannon and not a PCP? and if so what did you do to stop it or does it need to go back to the factory before something catastrophic happens to me or the gun. Till I get feedback on this issue, I'm going to turn the hammer spring adjustment back some and see if that stops it because when it happens It's definitely not backyard friendly any more. Thanks
.25 caliber Bullboss loud then quiet then loud again???
- Thread starter heath
- Start date
Seems like the valve is open too long and in fact is still open after the pellet leaves the barrel. This is why the increased sound doesn't translate to increased velocity, just wasted air. As you said, back down on the hammer spring until it never happens over the entire operating pressure range of your rifle's air tank. It is typical that the valve stays open the longest with the least pressure, since that air pressure is what closes the valve.
Upvote 0
Sound like you may have something hanging up the hammer. Causing increased dwell time. Try cleaning the hammer bore. 2nd, with the high hammer spring tension. There is a possibility that if you had shoot the tank to low on pressure. You could have bent the pop valve stem. If this was the case it could explain the inconsistency of your noise. The valve is easy to check. Just remove the tank, degas, unscrew the valve end, remove the white keeper. The the valve pin and spring will fall out. Just roll the valve on something flat and look for a bend. Good luck Mont
Upvote 0
Thank you for your response. I really do appreciate all the feedback you all are giving me. The problem was over tension on the hammer spring. I dialed it back 2 and 1/2 turns and now after 8 mags haven’t had the problem since. Happy with the shot count, 36 per fill and it’s pushing 25.39s @. 955 on a fresh tank of air and 860 with 31.4s Grizzly Slugs. I just find it amazing how 6 grains can produce 100 FPS less....The chronograph doesn’t lie....that often....nor does the math. Either way, the critter getter is back in action and is once again very pleasant to shot. Thank you for your advice and interest in her issue.
Upvote 0