Home Forums Reloading Big Game Rifles 7x57 bullet choice..

About the only thing I can take issue with is a modern rifle in 7x57 can be loaded up to or use 7-08 data. I have three rifles chambered to the 7x57. A Ruger #1A, Winchester M70 Featherweight and a custom based on an FN Mauser that used to be a .270 Win. so the action is strong enough. I have had no trouble working up to 7-08 standards in the Ruger and M70 but that Mauser is a bit of something else. Case in point. I've always heard how the 7x57 made it's reputation with 173/175 gr. round nose bullets so digging through the data I have on hand I determined XX.X gr. of powder Y would deliver the roughly 2300 FPS the round was supposed to deliver. I ran three rounds over the chronograph with each of the above mentioned rifles. I'm going from memory here but the Ruger was the slowest at IIRC about 2320 FPS. The M70 was a bit quicker at 2340 FPS and that Mauser 2450 FPS, a full 120 FPS over the combined average of the first two rifles. I later question my gunsmith who built the rifle about the throat and he said he used the standard long throat found in most 7x57 rifles. That rifle has the tightest chamber of any rifle I have ever owned. That slight bulge that a fired cartridge case get from lying in the chamber is almost not there on brass fired in that rifle. Could that be the cause? What bothers me is how quickly pressure rises regardless of bullet seating or primer. I would think I could get decent velocity with less powder due to whatever is causing pressures to rise so fast but so far no go. Accuracy is no problem as the higher the pressure goes the tighter the groups. I cannot go much past what pressures Winchester and Federal load their ammo to without running into problems regarding pressure. Damn thing is driving me sane. Anybody have any ideas????
Paul B.