Well, I know this is an old topic. I bought four boxes of this stuff a while ago without knowledge of this thread. My rifle hated this stuff. I have a rifle length gas tube too. It would fire the initial round and jam. Since I reload, I figured what the hell, pull the bullets and do a little experimenting. The factory load of powder is 46 grns; I loaded 20 with 44.5 and another 20 with 43 grns last night using the Top secret stuff I dumped from the cases.
This morning I went to the range to just to see if the rifle would cycle, good news.... It cycles both rounds, and I was hitting steel on the 300yrd line. I didn't stick around to check accuracy on paper. I was just curious to see if I corrected the cycling issue. My experiment was a success to that extent.
Before you ask, I was bored and felt like a mad scientist last night. 🧐