Automag Classic shootdown problems

[Gerbrauder]

I recently got a 20oz anti-siphon tank for my automag classic and replaced the regulator seat and on/off top and o-rings. Before I was running on CO2 without anti-siphon through an expansion chamber but the gun would freeze up within the first game. Now it works great except that after about 350 to 400 shots from a well filled 20oz (anti-siphon) tank It acts like it's out of CO2. The velocity drops to nothing and it does the burping and sputtering thing. Degassing and waiting does not help, when I hook it up againg it's the same. And if I put the same tank onto my friends autococker it shoots perfectly. Does anyone know what's up? Thank you for any information at all.

[italian_animal]

If you are playing in cold weather it doesnt matter if it is an anti siphon it will still freeze.How is you gun set up? Read your manual(Constant Air Tanks)

[Gerbrauder]

Well, the valve assembly is mostly stock except for an 8-hole mod. I'm still using an expansion chamber (Psycho ballistics x-chamber) and the weather I was playing in was not that cold, maybe 55 to 60 something degrees. I got the gun used not long ago but it seems like it was pretty well taken care of. Could the 8-hole mod be giving me trouble?

[athomas]

The cold weather has an effect on the gas consumption of any gun using CO2. What was the velocity setting of the mag while you were using it? A higher velocity setting in colder weather exagerates the gas consumption problem for CO2. That being said, you should still be getting more shots that that if you are getting a good fill.

The cocker will still cycle after the mag appears to be out of gas because the cocker will operate on less input pressure.

Is there a level 10 bolt on the mag? How long is your barrel? Is there a lot of porting in the barrel? A really short or heavily ported barrel will be hard on CO2. A very long unported barrel will also be harder on CO2.

The 8-hole mod shouldn't have any effect on your performance, especially consumption.

[Gerbrauder]

I'm using a 10 inch pro-series barrel (no porting) and I've got no level 10 bolt either. And my velocity was set pretty low, somewhere around 300 fps.

[athomas]

Dropping the velocity by as little as 10 or 15 fps will have a bid effect on efficiency, escpecially in cold weather. Setting the velocity at 300 is high. Try setting to 270 or at least down to 280 when playing in colder weather. 280 is a good velocity to operate at all the time. It provides a bit of buffer for any fluctuations your gun may experience without becoming dangerous.

Your barrel type seems ok. I don't know why you would be getting that bad of efficiency. Maybe the CO2 fill(s) you have gotten weren't topped up all the way.

[Gerbrauder]

alright, thanks for all the help, I'll try setting the velocity lower.