I sold my b51 and got a b50 gotta vent a bit
and i really regret it !
i had converted it to .25 and it had a short 19″ barrel pumping out 830+ fps with 42 grain EJ, it was smooth and funtioning well
got a b50 in .22, from day one there has been problems, on a full fill it would only do about 400 fps with jsb ! and the bell curve was terrible…generally they should do about 28-32 fpe, the rifle had arrived cocked…so i assume it has been cocked from day one !
the the hole in which the cocking arm slides has been drilled oval by the factory so theres quite a bit of play
2 orings where squished, 1 in the transferport, and one in the check valve
check valve died on fill number 10….they use a piston in the QC nippel…when filling this pop out of the QC and is stopped by the airfilter, no problem if you only pump up the gun, but filling from scuba pops that piston out too hard, and the airfilter got messed up and….so i had to make a fix…the oring in the check valve died somewhere between fill 10 and fill 20….giving a slow leak….put a quality oring in there and all is good…my b51 was the same…only took a little longer to fail
barrel was a tiny bit off to the left, loosen some of the set screws and that fixed that
i got a new hammer srping in the mail pretty quick from the dealer…which raised the speed to about 600 fps…still not quite enough
got a hint from a tuner of the B50’s saying to try remove the screw holding the safety, and the speed went to nearly 900fps, so it was clear theres a vacume forming behind the hammer….after doing the mod so you can adjust the hammer screw from the outside it settled down at about 42 fpe with EJ not too bad…and the bell curve alot better, but great.
today the .25 barrel i ordered from LW arrived, first the .22 barrel had to come out…and BAM has changed how they mount the barrels…in the old days it was 2 orings and glue, not so today….today its glue and a pressfit barrel that is pretty darn stuck on there good…
i heated it up and i saw the glue come out and burn off…but still barrel was stuck…the reciever was starting to glow it was that hot…and i decided to cool it down…then tried heating it once more, and that apprently did the trick the barrel came loose….but the bluing had suffered badly…..
and i got .25 machined to fit…added 2 setscrews at the top of the reciever so i dont have to glue the barrel in place
the valve got the transfer port enlarged, the endcap drilled in a couple of spots, and the valveseat was enlarged just a little bit too
the reciever is allready from the factory drilled out to .25, i plunged a reamer through just to make sure….mounted the barrel and shot some kodiacs…..875 to 930 fps….not really impressive, considering its a 24″ barrel.
i left the barrel 16mm OD for now, and it freefloats very close to the tank with ever touching it….but im going to add a riser and a shroud to it, once i have solved the question of the missing power….
it might be the valvestem it self and the delrin….as on my old b51 the valvehead broke off…and i made a new one, byt heating up the stem and removing the hold plastic leftovers…then heating it just enough that it would melt into the new delrin piece, i might not have pushed the pin as far into the new delrin piece, and there for ended up with a valve that can open further, making more power….
ohh another change they have made is to the hammer…the spring guide used to be a loose insert, it is now one piece with the hammer, only a big deal if you want to lighten it
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