I am gearing up to get serious about cast in my black rifle. I have worked up to about 13 gr of 2400 under a 225-462 with a gas check. This is 2 gr over the max that my old lyman book lists but there is no high pressure warning sign such as flattened primers and they do not eject from the rifle, they only partially extract. I do not want to go higher with the 2400 because I am already over the listed max. So I appeal to the more experienced, can someone suggest a minimum charge of a powder like IMR 3031 that will function through an AR. I saw that someone was using IMR 4227 but that is still kind of fast in my opinion. I think I need a slower powder to accomplish what I want to accomplish here.