SamL..You can form 30 Major brass from 7.62×39, although the only reason to do so would be price. Remember, the Grendel brass is not only very good quality brass made by Lapua, but also has small primer pockets and small flash holes. IIRC, there are also internal differences to handle the pressures better, such as thicker brass in the web area. I never had much luck using x39 brass at br pressures and didn’t pursue it much, with good brass being available that only requires necking up and turning, in the form of 6.5 Grendel brass from either Lapua or Alexander Arms…which is the same brass as the Lapua but with the AA headstamp.
To make 30 Major brass from x39 brass, you actually start by pushing pushing the shoulder back a few thou, then fire form. You gain capacity by having less case taper and a 30° shoulder.
The x39 has quite a bit of taper and only a very small shoulder.

Accuracy is when they are all in the center.

Sorry, couldn’t resist.

This wasn’t a dig at your cartridge, purely a statement of the almost cyclic evolution of a cartridge from 30 to 30 calibre (well .3105 to .308). One designed for short range killing effectiveness and weapon handleability, the one for punching holes in paper as accurately and efficiently as possible.

Personally I have a 6 mm PPC rifle (RPA Interceptor) and I’ve had one in 7.62×39 (CZ 527 Carbine), so I’m quite aware of the difference of bang and punch. Actually, the 7.62×39 was remarkably accurate for a mass produce plinker, sub 1″ groups at 100 yards isn’t bad for such a rifle. But yes, finding high-quality suitable-weight (110-125 gr) bullets was neigh on impossible.

Neil

PP Mauser got his inspiration for the bolt action from the latch on a privy door. The 7.62×39 is closely based on the 7.9×33 Kurtz.

Bottom line: every innovation is from standing on the shoulders of giants. We should all be good with that.

I’ve been shooting a 30 Major for years. Very nice, very predictable cartridge.

BTW, it’s worth talking to Mike to get the story of how it came to be as a benchrest cartridge.

The cartridge makes me chuckle though. Start off with the 7.62×39 Russian. The Russian’s then modify it, necking it down to 223 for deer hunting. The US bench rest guys then modify that, necking it up to 6 mm and blowing the case out making the 6 mm PPC. Someone takes that case, necks it out to 6.5 mm, making the 6.5 PPC. Alexander Arms takes that and makes the 6.5 Grendel. Then finally Mike takes the Grendel and necks it up to 30 calibre, making the 30 Major. From 30 calibre, back to 30 calibre. OK, the original uses 31 calibre bullets, but the bore is still .300. Talk about almost coming round full circle

Editor: Great commentary Neil! From 7.62×39 back to 30 Major, stepping down in bullet diameter and back up again, bit by bit.