Forming 6.5 grendel brass

[sanchoman]

I am new here. I have seen a few videos of guys forming 6.5 grendel brass from 7.62x39. I can definitely see why people would, due to price and availability of brass. Have any of yall done this? Any issues?

 

[JohnW...ski]

I haven't done 6.5 Grendel from 7.62x39 but I have done a lot of forming for other cartridges. You should be able to form it with your 6.5 Grindel die in one pass. If my memory is right the Grendel shoulder is slightly ahead of the 7.62x39 shoulder so yo need to form it with a slight step in the shoulder. to get propwr headspace. Just remove your expander ball and decapper and adjust the die above the shell holder and form a case. Try it in your chamber, it will probably be too long, adjust the die down on small increments until the cartridge will fit in your camber and the bolt will close. At that point your neck will be too small because the expander was not used. Replace the expander and decapper then run your case through the die and seat a bullet to see what your neck diameter is. If you have any fired cases from your rifle measure the neck the fired case, if it is .002 or more bigger in diameter than the dummy case neck with the bullet you are good to go. If you have a really tight chamber there may not be enough neck clearance and the necks will have to be turned, at that point you need to ask yourself if the project is worth the work.

If you do not have to turn the necks run all your cases through the adjusted die with the expander ball and decapper. Check overall case length and trim if needed. The cases will be ready to load. The first firing will fire form the cases to your chamber.

 

[Laurie]

7.62X39mm is normally Large Rifle primed whilst the Grendel uses a Small Rifle primer much better suited to the modest powder charges employed.

Lapua cases also use the smaller (1.5mm) diameter flash-hole as per its other SR primed precision cartridges - 220 Russian, 6mm BR, 6.5X47L, SR primed Creedmoors and suchlike. As with the SR size primer, this also helps give more consistent ignition and performance. (PPU 6.5G brass is SR primed these days, but with the larger flash-hole, and I suspect Hornady likewise but can't confirm.)

The larger size primer, or rather the considerably larger pocket swaged into the case-head to accommodate it, makes for a noticeably weaker case-head that will expand much quicker and so give loose primer pockets. Original PPU Grendel brass was Large Rifle primed and users complained its life was unacceptably short. (PPU has since changed to SR.) Obviously, the rate of expansion / loosening depends on loads / pressures, but even so it seems a poor idea to put in lots of work as @JohnW...ski outlines in the previous post to end up with a case that might only last a few firings.

The Lapua brass is superbly made, and also very strong. Sadly, its production has been 'temporarily discontinued' recently as demand for Lapua cases has gone through the roof in the last year, at least partly caused by the Ukraine war. If you find any around, I'd say buy it, even though it's rather pricey.

 

[5spd]

I've made lots of Grendel from 762x39, nothing to it, large primered, no issues, shoot the same as standard loads in my rig.

 

[mac86951]

+1 made a bunch myself too; use imperial die wax for lube, it's a big step down, but you can do it in one pass. I lost about 1 outta 5 until I learned to set the die high and partial size the neck before I set the die to final depth and FL size the rest, making it two passes using only one die.

Large rifle primers weren't a problem for my Grendel loads, but you.may find max pressure signs earlier. That really depends on a LOT of variables, so apply the default statement of work up your loads and see.

You may find that annealing, trimming, neck turning may be beneficial, though buying Lapua 6.5 brass may be easier in the long run.

Fire forming is needed, I was using the 85gr sierra HP over a mid to max load of h335. Darn if that wasn't a surprisingly accurate too.

-Mac