qb79 question ?

[neithan]

I have my qb 79 running on an ninja 13ci tank at 850 psi and was making 600 ft/s with just a couple of hammer spring shims but i wanted to get the same power at 650 psi for more shots per fill. so I decided to remove the filter and cut the piercing pin out of the valve and test at 850 psi before lowering the reg pressure. when it went back together I now have less power than before  at 850 psi

any thoughts on why this is would be greatly appreciated

thanks!!!

[mikeiniowa]

open the port in the barrel and use a fitted port seal....also open probe inlet ,you are way under normal operating pressure..remove shims

[neithan]

thanks mikeiniowa I will try it out.

[neithan]

what size of drill bit do you suggest for the barrel and probe inlets? also what size of poly tube for the transfer port?  I am trying for 12 ft/lb and at least 75 shots from a 13ci ninja tank. 

[mikeiniowa]

for .177 no bigger than 4mm or .150, for .22 4.5mm or .170, port seal is where you can adjust flow might be the best place to start...

[neithan]

thanks mike for all your help.