Hi-Capa 5.1 FPS issue

[Rookie]

Well basically i was using Abbey ultra gas in my hi capa, and ended up blowing the o ring off of the piston head and cracking the muzzle. I brought an enhanced muzzle and enhanced piston head and fitted them but im now getting a low FPS around the 200 mark with 134a gas. Before i started using the ultra gas i was using the same gas as i am now and it was shooting a fair bit hotter than it is now. Anyone have an ideas what could be causing the problem ?

[Liddleman]

Re: Hi-Capa 5.1 FPS issue

have you tried it on green gas?

[Rookie]

Re: Hi-Capa 5.1 FPS issue

Nope, i assumed that it would do the same thing as it did with high pressure and blow the o-ring ?

[Stealth1911]

Re: Hi-Capa 5.1 FPS issue

Ive ran TM hi-capas on green-gas for years, my last one had been running green gas for 5 years and its still going now! theyre fine with it, so something else is a-miss with the pistol for it to have done that. have you checked the blowback unit for any cracks or damage as if its too tight on the o-ring it will try to blow the o-ring to get the gas out!

[Rookie]

Re: Hi-Capa 5.1 FPS issue

So is green gas any different to Abbey Ultra ? Im tempted to try it on green gas but i dont want to have the same problem again

[Stealth1911]

Re: Hi-Capa 5.1 FPS issue

green gas is stronger than abbey ultra.

it goes (in order of power - low to high)

duster gas (basically compressed air lol)
134a
abbey ultra
green gas (+propane, green gas IS propane)
red gas (hard to get in the UK)
regulated CO2
unregulated CO2

[Rookie]

Re: Hi-Capa 5.1 FPS issue

Hmmm, not sure if ill bother then, dont want to break it again. Ill take it apart at the weekend and have a look at the blowback and see if its too tight like you said

[Stealth1911]

Re: Hi-Capa 5.1 FPS issue

the blowback pistonhead should move with very, very little resistance, but enough so that you know its got an air-seal, if it moves without any it wont have a decent airseal and will be dumping all the gas into the blowback unit instead of firing the BB (hence crap FPS) but if its too tight and you throw a higher powered gas in there it will have a good airseal but at the same time a high resistance, this will tehn try to break whatever it can to get the gas out.