i figured today i would try some new powder as well as load some ammo just to run some rounds through to cycle the action. i did some more reading last night and this morning and found one bit of advice that i previously missed. when running a gas port in the carbine position, a slower powder should be used. Accurate #9 is relatively fast, but i have some IMR 4227 on hand, and that was a bit slower. loaded some up on the low end of the scale, and what do you know, the action cycled every time!!!
so it appears at least from that end i now have a bit more understanding of how this cartridge works. i don't know how many people are actually going to read this post, but if you do and you post load data, i'd say it would be helpful to include the gas port position on your rifle.
now i have to chrono some loads and see just where i am on the speed scale. my intention is to only run subsonic loads through the AR. i unpacked my chrono so hopefully it still works.
andy b.