Pete,, My "Cross the Pond Huntin Buddy". By just replacing the valve with a Boss valve from Bryan & Associates you can expect 600 fps with 14.3 pells for just under 11.5 ft. lbs. You being a machinest,, I bet if you made a custom transfer port or bored out the stock one you may be able to get close to the 13 ft. lbs. you want!!

I can tell Ya though,,, the way you shoot,,,, them Bunnys would not stand a chance either way!!

Please keep us updated as to your progress. Tim. Forgot,,, a power adjuster/ and or a stronger hammer spring should get Ya where Ya want to be!! Also forgot,,,, you may want to move up to an 18" barrel for a tad bit more power as well.
