I have been working up loads for my 7 mm Mag. recently. Yesterday, I shot a 3 shot group with the following load - 175 gr. Sierre, 64 grs of old H-4831, Rem. cases and Win. Primer. No problems - group was 1 1/8 inch. No signs of pressure. Next load was 65 gr. of H-4831 - the bolt locked up tight after the first shot and I had to beat it open with a rubber hammer. Case looked fine.
No pressure signs, case not scratched up, primer pocket tight. I thought maybe the chamber was dirty even though I wipe it out each time I clean the rifle. The chamber looked OK. Should I try the load again or just stick to the 64 gr. load? The rifle is the old Vanguard (25+ years old) with the wooden stock.

Well, first of all, is it a Rem mag or a Wby mag? For a Rem mag you're just over book max.(by .5 grain). What are the temperatures when you're testing these loads? If you have a chronograph, what speeds are you getting? Lots of variables that have to be considered. I guess, short term, I would back off to a 63 gr load if I couldn't check these other variables. I don't think that the make or age of the rifle makes any real differance. Good luck - Dan

Hodgdon data for a 7mm rem. mag. with 175 gr. bullet is a max. charge of 58gr of H-4831 . When you say you are using OLD 4831, this would be GI surplus , which in my OLD loading books shows a max. load of 65.0 gr. I think your load got to hot with the OLD 4831 or you are using the newer powder and are way over max. Different makes of rifles in 7mm rem. mag., some have tighter bore then others, this will jump pressures also. One other thing,what is the length of you brass, do they need trimming?

I certainly wouldn't make a second try at a load that locked up the rifle. I would pick one case, neck size and load/shoot the 64 gr load and see how long the case lasts. If the case gives up in less than 5 your load is already at/over max pressure.

I've owned 2 of the older model WBY. Vanguards, a .270 Win. which I traded off, and a .308 Win. carbine which I still own. The bolt is not a beefy affair, so I would heed the first warning signs.

Thanks guys. I believe I will just use the 63 grs. until I can chronograph the load on a buddy's Oehler - maybe the speed will tell me what's going on. I knew that the 65 gr. load was over max. in most books, but I saw in Bob Hagel's book he used 66 grs. with the 175 gr. Nos. Part. I thought I would work up towards that load while watching carefully for pressure signs. The very first sign was the bolt locking up. I would like to get 2900 ft/sec, if I could do safely. Incidently, fishinfool I am a Louisiana boy also.