Forming 6mm ARC brass from something else?

[usbp379]

6.5 Grendel is about as straightforward as case conversation gets. Full-length size to bump the shoulder then trim. Trim quite a bit, actually. Without some kind of motorized trimmer it would be nigh on impossible.

Regarding conversion of 7.62x39 into 6 or 6.5; what are ya'll doing about the drastic AK case taper? About the only way to get rid of the taper is to load and shoot. Or hydro-form. Whidden and Hornady make water forming dies. I assume a few other companies do as well.

Sent from my SM-G970U using Tapatalk

[chinewalk]

See if you can get a cheap set of Lee dies for the 6.5 grendel. Form the x39 brass to 6.5 grendel and then run that case thru the ARC die. I go this way to make 6 grendel (243 lbc) and use 6mm ppc dies to load the 6mm grendel. I did find some 6.5 grendel brass a few weeks ago, but it was $1 each. I have plenty of x39 so I go that route.

Well, I'm in Oklahoma a week before Memorial weekend and the weather is doing what it normally does here this time of year ... rain and storm.

So, I grabbed up some 7.62x39 cases, 6.5 Grendel sizing die and 6MM ARC sizing die to attempt to cure the boredom and gave it a whirl. Going from 7.62x39 to 6.5 Grendel was easy. Getting the neck and shoulder formed thru the ARC sizer obviously took more time. I would put a case in the shell holder, raise case as far as it would go, screw the ARC sizer until it touched the case, size, turn die about 1/4 turn down and repeat until I had enough neck to stick out of my Wilson trimmer case holder then I would trim back to 1.475. After that continue on with slowly size/turn die until the sizer touched the press. I managed to get two usable cases out of ten with shoulders that weren't pushed back, so apparently I am still doing something wrong.

And it is still storming.

[Finster101]

I would think working the brass that much annealing might be a good place to start.

[usbp379]

I would trim back to 1.475.

Just a suggestion but I wouldn't trim that short. 1.490" will probably work better. You're going to lose a few thousandths upon firing when the taper is formed out of the case.

Sent from my SM-G970U using Tapatalk

[chinewalk]

6.5 Grendel is about as straightforward as case conversation gets. Full-length size to bump the shoulder then trim. Trim quite a bit, actually. Without some kind of motorized trimmer it would be nigh on impossible.

Regarding conversion of 7.62x39 into 6 or 6.5; what are ya'll doing about the drastic AK case taper? About the only way to get rid of the taper is to load and shoot. Or hydro-form. Whidden and Hornady make water forming dies. I assume a few other companies do as well.

Sent from my SM-G970U using Tapatalk

Load and shoot is the only way I know of. Burn more powder, primers and bullets which is why I haven't done much of this. But...I can't get ARC brass.

[chinewalk]

I would think working the brass that much annealing might be a good place to start.

Probably so. That might keep the shoulders from bulging.

[usbp379]

Look at item 933790347 on gunbroker.

Sent from my SM-G970U using Tapatalk

[chinewalk]

Just a suggestion but I wouldn't trim that short. 1.490" will probably work better. You're going to lose a few thousandths upon firing when the taper is formed out of the case.

Sent from my SM-G970U using Tapatalk

I will certainly take that into consideration if I can keep the shoulders from collapsing/bulging. I just grabbed the minimum trim length for the 6mm ARC to try to get around the bulging, but you are right ... they probably would be too short once fired and 1.490 is the max trim length.

Thanks,

Ed

[chinewalk]

Look at item 933790347 on gunbroker.

Sent from my SM-G970U using Tapatalk

Interesting! Thanks!

Ed

[Rapier]

I make 6.5 G out of 7.62x39 Win brass, only. The other brass is too soft or too thick. If you had a G chamber it would help, full length size, one pass, to fit the G chamber, trim and chamfer in and out. If you try to use military 7.62 brass chances are the neck will be too thick.
If you FL size to G then outside turn the neck, leaving a hair line not turned, lube in and out before you size to 6mm ARC you may have better results.
You will be fire forming the 6mm in any case, so you can headspace using the shoulder or set a bullet out to engage the lands to fire the cartridge. Fire the set out bullet with a starting load and lube the case before firing, so it can not stretch the web.
Normally, you might toss them, but today is not normal when it comes to brass avability.

[rockrat]

Hmmm. I go straight from 6.5G to 6G in one pass, but I don't push shoulders back. Annealing the neck of a few cases and try it again.
Usually this time of year its 100 degrees down in the Sooner state with occasional thunderstorms and tornado's.

[chinewalk]

Yes sir! I had one 6.5 Grendel case mixed in with some used 7.62x39 cases I bought a while back and it converted quick and easy in one pull with my ARC sizer die. It has a different POI than the factory cases with my 1/2" load, but it sure converted easy. The 7.62x39s aren't proving to be that easy, at least for me.

[usbp379]

Hmmm. I go straight from 6.5G to 6G in one pass, but I don't push shoulders back. Annealing the neck of a few cases and try it again.
Usually this time of year its 100 degrees down in the Sooner state with occasional thunderstorms and tornado's.

Again, the issue with 7.62x39 to 6 ARC is the case taper. Trying to work a new shoulder into the case that's essentially right on top of the taper is likely going to result in a buckled case. To make it work the brass must be incrementally worked down and/or the taper needs to be blown out via something like hydro forming.

Sent from my SM-G970U using Tapatalk

[chinewalk]

Again, the issue with 7.62x39 to 6 ARC is the case taper. Trying to work a new shoulder into the case that's essentially right on top of the taper is likely going to result in a buckled case. To make it work the brass must be incrementally worked down and/or the taper needs to be blown out via something like hydro forming.

Sent from my SM-G970U using Tapatalk

Agreed, more buckle than not with the tools that I have.

[usbp379]

Agreed, more buckle than not with the tools that I have.

What about sizing and trimming just enough to get a casing to chamber? I imagine you'd be fractionally close to fully sized / cammed over at that point. But it might be just enough to keep from trying to push a new shoulder into the case taper.

Sent from my SM-G970U using Tapatalk

[chinewalk]

That might work, but I would be a little uncomfortable with doing it in an AR. I might just go buy another box of factory to get the brass. Thats what I did to get the ones I have, but they are getting pretty wore out now.

I appreciate all of the suggestions!

[usbp379]

That might work, but I would be a little uncomfortable with doing it in an AR. I might just go buy another box of factory to get the brass. Thats what I did to get the ones I have, but they are getting pretty wore out now.

I appreciate all of the suggestions!

Any luck?

Sent from my SM-G970U using Tapatalk

[chinewalk]

Hey! Good morning!

Actually, no but I have been distracted with cleaning up the mess on the property after the flood that happened a while back. The property where my range is got hit hard and I had to spend some time on a tractor getting logs out of the way and building a road back. Then my neighbors road wound up in my four acre yard which looked like a gravel bar which I finally got cleaned up Wednesday. And now it is raining again.