I load 300 grain Sierra sports masters at 2222 FPS over H322 in my 22" 444 marlin lever gun with the old 1:38 twist microgroove barrel. I can hold 2" at 100 pretty easy with iron sights and shot a 4" group at 200 the other day. First I've shot it on paper at that range. Not too bad considering my sight covers about 6 Moa. That bullet is very tough and did very well in the bullet tests on the marlin forum a few years back. I think it stops opening up around 1700 FPS and punches right through. Haven't shot anything with it yet unfortunately. Could probably get it close to 2400 in a bolt gun.