by vulrath » Thu May 31, 2012 8:23 am
Crosman vs. JT vs. Brand-X doesn't matter. Companies build the 12gram capsules to industry standards to ensure cross-compatibility (as do most airsoft/paintball gun manufacturers - they don't know what you're going to do with their products after you buy them). That shouldn't matter.
As to your gun, does it all jet out as soon as you put the capsule in the gun, or does it slowly hiss out over time? Check to see if that o-ring around the puncture lip is damaged or missing. It's possible it's there and in tact, but has hardened (in which case you'd need to replace it) or it's missing (again, replace it - noticing a pattern yet?).
A local paintball store should sell the o-rings you need. just go in and ask for the o-ring that goes against the capsule of a 12 gram CO2 adapter.