Heretic

I had the same problem with a 6.8SPC. After the gunsmith was able to get the rifle to reliable cycle with combat loads but i couldn't get it to cycle with any other factory loads, I pulled everything and measured/weighed everything. My buffer spring was too long. I received a rifle stock spring in the carbine stock kit I bought. Never thought to check it. Also I went up to an H2 buffer. Just more food for thought.