I loaded 4198 with great results on paper . The pressure curve was just about 2" to long for the carbine gas length , the stroke was was just enough short that the lock open was all on the mag follower . Just standard GI parts . I haven't reshot any of that in the 20 rifle gas 5R barrel .

H322 didn't get me the groups , about 2.5" vs 1.5" .