Xavieus Buffer and gas system should have little effect, albeit a configuration with a lot of bolt bounce could be an issue. However with your buffer, I don't think this will be an issue.
Unlocking the trigger too soon is the most likely culprit. If you hold the trigger while slowly lowering the bolt into battery, how close is the carrier to fully closed when the hammer falls? Should be about 0.2" or closer.
A lever that is too tight in the dovetail, or an over ground trigger tail, are the two most common causes.
