As I have stated earlier, the rifle that I have has the "Uberti" style chamber which, apparently, folks got upset enough over that the chambering was changed to emulate the original specifications. However, in my dabbelings with my rifle, I found that I did, in fact, gain about 5 grains of case capacity with no problems concerning bullet seating and so forth. When I went to 76 grains of Swiss1½, I did get an increase in velocity up to just under 1500 feet per second. However there was a noticeable increase in recoil to go along with this load. I have used and still do use 348 cases, 50-90 cases along with Jamison cases. The Jamison cases come sized to original specs so I have to fire form them to my rifles chamber which is no big deal. Since my rifle is of the earlier version with the larger chamber, alot of what I do may not pertain to you folks with the newer rifles with the original size chambers but thought that it would be worth passing along anyway. And as I have also stated before the bullet that I use is a Hoch custom bullet cast to 350 grains with a 16:1 alloy.