I have played with this in 444 brass. I wasn't going for huge power, but did get good accuracy. It is easy to do and you might have to adjust a little. Remember this is the sb-1 shotgun frame not the sb-2 rifle frame so a little caution is in order. I haven't done anything with it since last fall. I was actually thinking of developing loads in 410 brass shell. Would be good for the shotgun only areas here in MN. I have been workig on other projects and plan to get back to it. It is also called the 450 mongo.