I slapped the CZ .22 upper on my Bushy M4gery lower. After about 600 rounds I'm noticing a 2 round blast if I hold the trigger. It never ceases to startle me. Just wondering if anyone has experienced this. Remington Thunderbolt and Winchester Super X high velocity, produce the least amount of jams (mostly failure to eject). I have an Accuracy Speaks single stage trigger and I clean the gun after every couple hundred rounds using CLP. I love the gun and it's very accurate, but I'm concerned about the unreliability. Any tips or advice would be appreciated.