QB78/AR2078A Pressures

Cooler weather is coming on. CO2 won't work well below about 65F.

If we don't have a basement or heated garage what do we do?

I was wondering what the safe pressure would be if a person wanted to pump it up with an PCP pump.
I know it would take at least 1000lbs, CO2 gets that high. I don't want to strech the guns limits.

I would like to be able to shoot a QB-7X outside when the temp is between 30 and 65. Any Ideas?