Like I said I am new to reloading and maybe I am making more out of this than there is but I don't want a 20 rnd mag going full auto or have it blow back in my face but there are those like you who I rely on who have a ton more experience than me so if you guys have used them with no issues they must be ok, as far as my M1A goes it's in very good shape and has not had any issues with slamfires.
The load I am looking at is :
LC Mil-surp MG Brass trimmed, cleaned and crimp removed
IMR 4895 powder
Fed 210 primer
147g BTSP