7.62x39mm IMI Brass Loads

C

CowTowner

New member
I started to load Sierra 125 gr. Pro Hunter bullets for my Enfield K and after checking with Hodgdon, found Max load of H322 at 31.5 Grains. This little conversion likes the loads as fast as I can get them.
However, when I Measure the charge and load the new, never fired IMI cases, I can see that seating the bullet will compress the charge and Hodgdon says nothing about a compressed load.
Anyone loaded with IMI brass for the 7.62x39mm?
 
It is made to military specs, so it may be thicker and have less capacity than commercial brass, which can be at the larger end of the capacity spectrum. Also, if your other loads went into cases that had previously been fired and then resized, the IMI is likely closer to the minimum outside dimensions when new than what comes out of your resizing die—just measure both to confirm this—and will be bigger after you shoot it and resize it once. However, as a precaution, as when changing any other component, you should follow the standard advice to reduce your maximum load 10% and work it back up with the new component.
 
31.5 grains of H322 is 2.5 grains over the max load given by Hodgdon for a 125 grain bullet. You do not "find" the Max load. You do not exceed the published Max load. However, that may be why it's compressed.
Like Nick says, IMI may be milsurp brass. It is usually a wee bit thicker than commercial brass. You must reduce the Start load(28.0 of H322) by 10% and work up if using milsurp brass.
 
IMI is not actually milsurp, but it is mil-spec. I've got a good bit of their .308 Win and .45 Auto Match brass. The only funny things about it are the heads are not as hard as Lake City and it has European-size minimum primer pockets on my copies. Those run about three-tenths of a thousandth smaller than U.S. minimum for large primers (both pistol and rifle), making initial primer seating a bit hard. I actually run mine through my Dillon Super Swage 600 primer pocket crimp remover before loading it initially, and it widens them slightly and makes primer seating a lot easier.
 
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