Tuning BSA Ultra SE In .22: What FPE From Tuning?

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I get about 16 fpe from my .22 BSA Ultra MMC. It's un-modded.

I really love the little gun, it's accurate, pretty small, and very reliable. I'm guessing it's about 15 years old and the only issue I had was the fill valve o-ring was so old it became hard and brittle.

MMC action is a little cumbersome but I don't have any issues with it. Only negative is the tank is a bit too small, maybe 18 consistent shots.

I am unsure how you could mod the 12fpe version up to 16 fpe ... and it might be very hard to get it over 16fpe.


 
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My dad has claimed ownership of my Ultra SE .177 so I haven’t been into the gun in years. If I remember right, it has a hollow probe. If the .22 has one I would make a pin probe for it, open up the ports to max for a .22 and put a reg in it. My Ultra is regulated with a larger transfer port and different hammer spring. It’s shooting 8.4’s 830fps for 36 shots without even leaning on the gun real hard. I always thought about a .22 just not enough to buy one. I originally got the gun because of the tube size. Easy to pump, short and light. If I can easily get my regulated Prod to shoot 14.3 at 725fps for 24 shots, an Ultra .22 wouldn’t scare me. Might have to be happy with 14.3’s to get it humming but a 14.3 beats the heck out of a 8.4 or 10.3.
 
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I just finished up tuning a Ultra JSR in .22 cal. Customer only wanted 12 fpe and QUIET !! ( Using a HuMa reg & shroud ) So we first went about getting the breathing opened up so it was more air efficient and not breathing so strangled. valves insert removed, transfer port drilled out to @ .140" and one of the poppet spring preload washers removed.

Stock hammer spring w/o a top hat weight and its shooting @ 22 fpe with reg at @ 110 bar .... Too hot !!!

From there we started dropping reg until at @ 80 bar, replacement of hammer spring to a .045" wire, shortened until hammer was just in free flight and we're at 12 fpe.

SUPER easy cocking, no hammer bounce and just stupid quiet !!! ES over the chrony @ +/- 3 fps



* These air tanks are SOOOOO small that using an Ultra as a higher power carbine won't have many good shots ..... IMO



Scott S
 
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