7.62 x 39 Brass Conversion

[Dave Nowlin]

How much luck have ya'll had making 6.5 Grendel out of 7.62 x 39 brass?

[mtnlvr]

I've converted maybe 100 pcs of new Hornady with good success. Wasn't too bad. I wouldn't do it unless there was no other option.

[lazyengineer]

How much luck have ya'll had making 6.5 Grendel out of 7.62 x 39 brass?

There are countless threads on this. For me, I've had great luck. There are no additional processing steps required, and you don't need to fireform before calling it good. Basically adjust the die a touch and just run it. Can get about a 10% initial loss rate of collapsed necks sometimes - oh well. As to life, I'm on 6th cycle now with some of it. A couple tips:
-Case capacity is significantly different - it needs it's own load data.
-Brand variability is quite large, segregate by headstamp for sure.

Some of the best accuracy I've ever gotten was with once fired 7.62x39 brass that wasn't even fireformed yet.

I really don't know why people treat it with such disdain - it's as easy to process as Grendel Brass and shoots as well.

[Dave Nowlin]

Thank you Sir. In the past I have made .30 Herrett and .309 JDJ as well as .300 Blackout. All of which used brass of a different caliber. I've also used .300 WSM brass to make .270 WSM In fact to shoot .309 JDJ you must use .444 Marlin Brass as there is no .309 JDJ brass.

[VASCAR2]

Here is a link to a google custom search for this forum. It works real well for finding specific information on this forum.



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[Constitutionalist]

I made about 600 rounds worth back when Grendel brass was hard to find. The fire forming loads were surprising accurate and the brass worked fine. I now have a bunch of Hornady so the fire formed stuff is on the shelf (loaded) for a rainy day.

[lazyengineer]

I made about 600 rounds worth back when Grendel brass was hard to find. The fire forming loads were surprising accurate and the brass worked fine. I now have a bunch of Hornady so the fire formed stuff is on the shelf (loaded) for a rainy day.

I have a pet-pondering on this. In my observation, Grendel chamber necks are cut very generous in diameter size. I think to better serve running steel? Using 7.62x39 brass, which will give a thicker neck wall, and so more fully fill the neck portion of the chamber. And so, does this give better accuracy?

[VASCAR2]

I have never observed any difference in accuracy between my fire formed 7.62x39 brass compared to Lapua or Hornady 6.5 Grendel brass. One caveat is I used mixed brands of x39 brass as I only had about 100-150 a friend gave me. This was early on when I bought my first 6.5 Grendel and I didn’t have much 6.5 Grendel brass.

The x39 brass will work and I have a few still loaded with 85 grain Sierra Varmint to be shot hunting where I might not find my brass. Once these are shot I’ll probably never reload them. Like others mentioned you get a few collapsed cases in sizing and primer pockets get loose after a couple loadings.

[Dave Nowlin]

I know some of you appear to look down on this practice but since 6.5 Grendel brass at present seems as rare as hen's teeth, those of us recently into the 6.5 have to do something. Th aggravating thing is you can't find 6.5 inside neck reamers either.

[Dave Nowlin]

So far I have thoroughly lubed and sized over 1 hundred without a single crushed shoulder. I am using an old RCBS single stage press made back in the 70s with RCBS dies.

[VASCAR2]

I use a Rock Chucker I got in the early 80’s with Hornady 6.5 Grendel dies. IMI brass seemed to cause more crushed pieces of x39 brass than other brands of brass. I completely understand about lack of availability of 6.5 Grendel brass. I bought my first 6.5 Grendel in about 2009-2010 and everything in 6.5 Grendel was in short supply.


If you have once fired x39 brass it is worth using if you don’t have 6.5 Grendel brass. I doubt it is worth buying new 7.62x39 brass cases unless you get them really cheap or lucky where a friend gives you x39 brass.

[Dave Nowlin]

I bought 250 pieces of once fired 7.62 x 39. I threw away about 3 because they had small primer pockets. Around here right now it is much easier to find large rifle primers than small.

[StoneHendge]

I've recently come close to putting closure on close to 3,000 rounds of converted Starline 7.62x39 in a 243 LBC (aka 6 Grendel) with much success. That barrel is pretty much shot out (5k ish) and I'm going to put closure on a long thread about it when I do. I've got about 150 rounds of MOA ish ammo ammo left to shoot and then I'm going to take what brass is left and load it with 400 or so really gnarly pulls with some Magnum LP primers I have absolutely no other use for and do close range speed practice.

My biggest takeaway is that using a Large Primer results in faster ignition and hence and earlier pressure peak. The end result is that using traditional powders for the caliber results in lower attainable velocity. That wasn't a big deal for me since I used x39 brass for mild loads.

I didn't find that the LP results in shorter primer pocket life. In fact, I got better pocket life out of Starline LP x39 brass than I did out of Starline small primer 6.5G brass that I converted to 6 ARC. My x39 loads were milder, though.

You mentioned crushed shoulders. My theory is that AKs etc. are so violent with extraction that the rim gets bent. If you use range brass, the case mouth can be slightly off center as it goes up into the die and the crushing begins.....

Use fireforming loads to practice standing speed and double taps. I use 1/3 and 1/4 USPSA target photocopies at 15-25 yards to simulate 50-100 yards (recognising that impacts will be 1.5-2" low. But it takes bullet flight out of the equation).

And if your not annealer, don't worry about annealing (but if you are, annealers are gonna anneal!).

Best of luck!