Since the beginning of the year, I have had a 308 Baer heavy BR rifle which I have been trying to develop loads for. I have been loading for this with Norma 340 Wby cases that are necked down, fire formed then prepped and neck turned.
So far, I have been disappointed with the velocities I can achieve from this rifle before experiencing expanded primer pockets. For example, I am running a Lapua 185gn bullet and of have loaded this up to 81gn of H4831. With 81gn of powder, the primers just about fall out after the second firing.
By comparing this data to the 300 Wby, I don’t think the loads are excessive. I tend to think the Norma brass is the culprit. Does anyone have a suggestion for a source of match quality, full length - belted magnum cases that I could use in place of the Norma cases? I tend to think RWS cases might be the best option, as Lapua doesn’t offer anything suitable.
Judging by equipment lists of major 1000yd shoots, there are a LOT of cases that I would broadly classify as 300 Wby improved chamberings. I would think a lot of other shooters have been down this path before me. Any suggestions?