Converting once fired 7.62x39 to 6.5 Grendel: Anneal before or after sizing?

[rmantoo]

Pretty much exactly what the title says: Should I anneal once fired 7.62x39 before, or after sizing down to 6.5 grendel?

For that matter, would anyone suggest I anneal before AND after for some reason?

This is my first time necking brass down. I've done about 20 so far. Wet tumbled, dried, lubed, then ran them through my decapping and sizing die. They ran through more easily than I expected, but I realized that there is probably already tension before I sized them from the first firing, and started wondering about it....




Thanks, Robert

 

[biffj]

Soft shoulders aren't always good for big changes. Sometimes when you do a major change in diameter you will end up crushing the neck down into the shoulder if you anneal prior to stepping down. You might try annealing a couple first and see how it goes. It would seem like the way to go but it doesn't always work that way. If you're sizing them down without annealing I'd shoot them first before annealing in order to get a good consistent program going.

Frank

 

[rmantoo]

Well... for me, in this particular situation, it looks like I should NOT anneal first... Annealed 20, liberally lubed them inside and out, and had 5 push the necks in. Lubed and sized the next 200 or so and didn't have a single neck or shoulder deform.

 

[biffj]

In truth I would sell off the 7.62 brass and buy Lapua cases for the grendel. Since they're made for the Grendel the brass thickness will be more attuned to the caliber and more consistent making more accurate ammo. If you're just blasting it won't make any real difference though....so have at it.

Frank

 

[Geno C.]

It’s also possible to just anneal the necks when trying to go down that far in one step. Annealing down onto tomhe shoulder like normal can soften them enough to make them crush like you’ve seen.

 

[MarinePMI]

In truth I would sell off the 7.62 brass and buy Lapua cases for the grendel. Since they're made for the Grendel the brass thickness will be more attuned to the caliber and more consistent making more accurate ammo. If you're just blasting it won't make any real difference though....so have at it.

Frank

Just to add, the other thing to consider is that the OP's brass looks like its LRP brass; which does hold up very well, and throws load data off considerable. I went down this route with PRVI/PPU Grendel brass, and they were considerably weaker than the SRP Hornady brass. The LRP brass only lasted a few loadings (3-4) before the pockets got too loose. The SRP stuff had 6-9 reloadings before I got bored with the cartridge, and put that rifle in the safe, moving on to other things.

 

[rmantoo]

Just to add, the other thing to consider is that the OP's brass looks like its LRP brass; which does hold up very well, and throws load data off considerable. I went down this route with PRVI/PPU Grendel brass, and they were considerably weaker than the SRP Hornady brass. The LRP brass only lasted a few loadings (3-4) before the pockets got too loose. The SRP stuff had 6-9 reloadings before I got bored with the cartridge, and put that rifle in the safe, moving on to other things.

This brass is about 30% ppu, 20% hornady, and 50% win... really only using it to get to know the process and whether to proceed with this caliber.

In truth I would sell off the 7.62 brass and buy Lapua cases for the grendel. Since they're made for the Grendel the brass thickness will be more attuned to the caliber and more consistent making more accurate ammo. If you're just blasting it won't make any real difference though....so have at it.

Frank

I may buy lapua eventually, but I'm only using this out to about 5-600 yards... don't care too much about sub-moa at these ranges: I'm mostly getting used to loading for 6.5G and trying to decide if I'm going to build a bolt gun in this caliber...if I do that, I'll buy new Lapua at that point.

I will say I've been AMAZED at how accurate my first development loads (using new starline brass that was included with my upper) were: Easily sub-moa at 100 yards. First time I've ever had that out of a cheap AR...this is a PSA 20" stainless upper. I got the whole package, upper w/bcg, dies, and 200 new starline, 50 once fired starline, and 46 123gr sierra hpbt, all for less than $200 with shipping.

It’s also possible to just anneal the necks when trying to go down that far in one step. Annealing down onto tomhe shoulder like normal can soften them enough to make them crush like you’ve seen.

I have an annealeez coming: I'll try that and see how it goes.