Just remembered and checked my notes: The case capacity issue is mostly for 7.62 LC brass. It’s almost a non-issue for 5.56 LC brass, from my notes. Like, oh, less than 0.3 gr diff between SAMMI cases and LC cases in 5.56/.223. I’d still start low and work up, of course.
In .308/7.62 — there’s a bit more that needs to be taken into account.
Sadly, I have very little -06 LC brass. Seems as tho none of the old timers I shoot with will part with it. They open a bolt and they move pretty quick for 75+ years old when jumping after their brass.
A friend of mine and I got access to the local FBI range a while back and volunteered to “clean up” after. We grabbed every 5.56, 7.62, and .40 cal case we could lay our hands on.
We had to clean them in a small rented cement mixer. LOL
I think we got the better end of that deal.