Alright, got a day off and decided to look into this issue. The suggestions about gas pressure/volume got me thinking. My DPMS bull barrel came with a gas block with a pic rail, it wouldn't fit under my handguard so I swapped it out. I noticed the set screws didn't line up with the divots on the barrel perfectly, but close...not close enough. When I pulled the handguard off I saw powder residue forward of the block, it was coming out from underneath it. I'm in the process of modifying the original to fit, just a little careful time with a grinder. We'll see if this works. If not, I'll look into the buffer and spring. Thanks for the help so far guys.