Posted: 1/16/2022 2:32:54 AM EDT
[Last Edit: Normlizer]
30 bullets aren't enough to do a proper test.
20.5 to 21.0 grains of IMR-4198 with the bullets seated around 2.200" should function fine. I use the H4198 variety (20.7 grains) with 52/53 grain Sierra Match Kings and they shoot lights out from rifles. Carbine gassed rifles run these 100% reliably. 20" rifle gassed rifles may or may not cycle 100% of the time until they are properly broken in.
IMR-3031 could use between 23.0 to 23.5 grains and shoot (function) reliably. I have used 22.5 grains with Hornady 60 hp flat base bullets and it's close to maximum with that bullet weight.
Reference online data (Hodgdon) to gain more insight.
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.