.312"/.313" 160 Gr Mould for 7.62x39mm W/O Crimp Groove

I contacted someone whose opinion I really respect about the question of whether a crimp groove is necessary, or even wanted at all on a bullet for the 7.62x39mm. I received a very detailed response, but under the circumstances, this person didn’t want to have his name used. I respect that request, and will attempt to pass along the pertinent parts of his response without giving you his name. He is, however, someone you would all recognize.

The recommendation was based on the existing Ed Harris design .312″ 160 gr, and suggested eliminating the crimp groove and bringing the diameter there and in front of it to a full .312″. The suggestion was to also eliminate the large single lube groove, and to replace it with two shallower lube grooves .010″ deep instead of the .016″ used at present. The lube grooves would be about .040″ wide, and would be contained within the .239″ area from the base of the bullet so they would all fit within the case neck of the 7.62×39 case. These would carry the same amounts of lube as the present design, but would stiffen the bullet with the larger diameter at the bottom of the lube grooves. The suggestion was to also increase the nose diameter for a better fit in most 7.62x39mm CIP throats. The specifications would also be for nose dimensions of .310″, .308″, and .305″, instead of .306″, .304″, and .303″ in the existing design.

These recommendations were based on optimizing the design for the 7.62x39mm CIP, and not compromising too much for a one-size-fits-all approach with every other .30 caliber bore. Even at that, this design should still work well as a lighter weight bullet for most of the other .31s (7.62x54R, 5 groove .303s, 7.65 Argentines, 7.7 Jap, etc.).

What do you think about this design?

Dave

Most, if not all, factory loaded rifle ammunition for bottle-necked rifle cartridges do not use a roll crimp. Some military type rifle cartridges, however, will use a collet-type crimp on the case neck. The collet-type crimping dies are easier and, therefore, cheaper to make than taper crimp dies, and this is why they are used.

For anyone who might be concerned about bullet set-back using a bullet design without a crimp groove in a gas-operated semi-auto rifle, I would suggest using the Redding Taper Crimp die to do a “light” taper crimp of about .002″ to .003″ under the diameter of the neck at the mouth of a sized case. This should not damage a cast lead bullet. Redding makes Taper Crimp Dies for most cartridges, including the 7.62x39mm. For example, to see the Redding Taper Crimp Die for the 7.62x39mm, go to: http://www.midwayusa.com/product/737623/redding-taper-crimp-die-762x39mm

Another option, would be to use the Lee Factory Crimp Die to do a light crimp. I prefer the Redding Taper Crimp Die, however, because it doesn’t work the brass as much as the Lee FCD.

Dave