BarnesX.308

I read this on the reloading board and was wondering if anyone knew anything about this. I've been reloading this cartridge for several years and my manuals range from 1970s to about 2002. The case capacity would dictate that this round has a lot more punch than the Mauser but I'm not aware of any new findings with pressures. Can anyone help?

diyj98

I don't know about being down to the 7x57 class, but most cartirdges aren't loaded to the pressures they were in the "good ol days". The official story is that modern pressure testing techniques have found many of the older top loads as being over pressure. My newer reloading manuals don't come anywhere near my old books from the 70's. The famous Elmer Keith 44 Mag. load of a 240 grain lead bullet and 21 grains of 2400 is no longer in any of my newer reloading books. It's considered over pressure by today's standards.

oldelkhunter

I have heard that it is prone to pressure spikes? What is interesting is that Federal never loaded heavy ammo for it and they have for the 300 and 338 win.

BarnesX.308

I have the old Speer manual with the stagecoach on the front and it has some hot loads. Is the 7mm Mag's downgrading documented somewhere or is it just something people noticed when looking at newer manuals?

frizzellr

Seems like they nuetered the 300 Win Mag a bit before they came out with the 300 WSM.

James B

The 7x57 is not on par with the 7MM Rem Mag for velocity. They are however close to equal in the kind of game they are used to hunt. The main advantage of the 7 Mag would be 200-400 fps edge in velocity. Many 7 Mags which I have had and others that I have reloaded for seldom reach published velocities without excess pressure signs. The manuals say that its because from one manufacturer to the next there is inconsistancy in chamber demensions. Many 280's that I have worked with will match the 7mm Mag ballisticly.

BarnesX.308

I can see where inconsistencies in chambers from rifle to rifle would warrant listing prudent loads. However, I have been loading this rifle with loads from these manuals for several years without any signs of excessive pressure. I would conclude that this particular rifle is safe with these loads. On the same token, if I picked up a 7mm Mag that I had never shot before, I should procede with caution. Does this thinking sound logical?

James B

That makes very good sense and is always a good idea. I have had five 7MM Mags. The only real lemon of the bunch was a Winchester. I could not safly get 3000 fps with any 140 grain bullet-powder combination. At the time I had my first 280 which would reach 3150 fps with several loads with 140 grainers. That one was a Remington 700 with a 24 inch barrel.