Fx impact barrels

Youd be surprised what a 357 cal can do in 20 inches high pressure fast burst
Not an FX, but I've got a 12"
357 that does 750fps with pellets, a 16" that does 850fps, without working really hard....just need about 2500psi big ports and and a fast opening valve.


For a 500mm and threaded I would recommend TJ'S 1:26, it is hard to beat at those power levels...someone like Bill Greathouse could machine you one....
 
Not an FX, but I've got a 12"
357 that does 750fps with pellets, a 16" that does 850fps, without working really hard....just need about 2500psi big ports and and a fast opening valve.


For a 500mm and threaded I would recommend TJ'S 1:26, it is hard to beat at those power levels...someone like Bill Greathouse could machine you one....
You got a link to Tj’s barrels