Can you convert .223 brass into 7.62x39 brass?

Shooter14854 said:

The title basically says it all. I convert .223 brass into 300 blackout brass using the RCBS short base dye and cutting it down with a saw. Could I re-adjust my 300 blackout jig to cut to the proper length for 7.62x39 and resize the brass? I can’t seem to find a thread on this. Thanks for the help!

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The base (head) extractor area is about .070" bigger on the 7.62x39. And about the same for the body.

No.

If someone has a foundry to return the .223 brass back into raw material and all the equipment to form 7.62x39 from raw material, they could though.

300Blk parent case is 223/556 is why that works, 7.62x39 can be made from 220 Russian the PPC family cases and 6.5 Grendel 6mm ARC. As stated above case base is quit a bit different

223 fired in 7.62x39 https://www.thehighroad.org/index.p...through-a-7-62x39-barrel-accidentally.791485/

243winxb said:

223 fired in 7.62x39 View attachment 1063111 https://www.thehighroad.org/index.p...through-a-7-62x39-barrel-accidentally.791485/

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Ouch! That was kinda what I thought would/could happen.

Post #5.
A good reason, I suspect, to not shoot .223 Remington through a 7.62x39mm AK rifle, left handed without a face shield.

There are resources to check cartridge case dimensions to see if they match. The cartridge articles at Wikipedia are free.

i painter my x39 AR green so i would not do that after i did it

But you can convert .223 brass into 6.8x39 brass.

Shooter14854 said:

The title basically says it all. I convert .223 brass into 300 blackout brass using the RCBS short base dye and cutting it down with a saw. Could I re-adjust my 300 blackout jig to cut to the proper length for 7.62x39 and resize the brass? I can’t seem to find a thread on this. Thanks for the help!

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No, well.....unless you're gonna be running it in a 7.62x39 AR, and you swap the bolt out with a 5.56 bolt...then I imagine it would work. Starline 7.62x39 brass is cheap, buy once, cry once.

Seriously, get a reloading manual and read it. Wealth of information.

EricBu said:

No, well.....unless you're gonna be running it in a 7.62x39 AR, and you swap the bolt out with a 5.56 bolt...then I imagine it would work...

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Once.

Better swap the barrel as well, unless you really like gas and maybe chunks of brass in your face.

Shooter14854 said:

Could I re-adjust my 300 blackout jig to cut to the proper length for 7.62x39 and resize the brass?

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Are you aware that dimensional drawings for cartridges are available, for free, from SAAMI?

^ and in every reloading manual I have.

Swampman said:

Once.

Better swap the barrel as well, unless you really like gas and maybe chunks of brass in your face.

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I think you missed the part where I said "7.62x39 AR". The devil is in the details.

People are liable to ask anything on here.

EricBu said:

I think you missed the part where I said "7.62x39 AR". The devil is in the details.

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I think you missed the part where the op was asking if he could form 7.62x39 brass from .223.

Or do you honestly believe that using a .223 bolt to shove a 39 mm long .223 case necked up to .30 caliber into a 7.62x39 chamber some how makes it a better idea than if you used a 7.62x39 bolt?

The problem here isn't headspace or proper extraction, it's massively undersized diameter that WILL cause a catastrophic case failure.

Since it has a bullet that actually fits the bore, it'd make the ".223 in 7.62x39" pic 243winxb posted look like no big deal (a .224" bullet in a .311" bore doesn't seal well enough to get pressure near as high as one that actually fits).

The devil is in the thread title...

stoney1666 said:

i painter my x39 AR green so i would not do that after i did it

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I put a green/brown laminated stock on my 308 Win Garand so that I could differentiate it from the standard 30-06 Garands.

No, the average handloader cannot make 7.62x39 cases from 223 Remington.

why would you want to turn 5.56 into a AK round. Like turning Apples into Russian Salad Dressing

Swampman said:

I think you missed the part where the op was asking if he could form 7.62x39 brass from .223.

Or do you honestly believe that using a .223 bolt to shove a 39 mm long .223 case necked up to .30 caliber into a 7.62x39 chamber some how makes it a better idea than if you used a 7.62x39 bolt?

The problem here isn't headspace or proper extraction, it's massively undersized diameter that WILL cause a catastrophic case failure.

Since it has a bullet that actually fits the bore, it'd make the ".223 in 7.62x39" pic 243winxb posted look like no big deal (a .224" bullet in a .311" bore doesn't seal well enough to get pressure near as high as one that actually fits).

The devil is in the thread title...

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Wow, you completely misinterpreted the entire reply and the point, and apparently you still don't functionally understand what a 7.62x39 AR is. Anyway, as per my original answer...NO you can't convert it realistically. And yes, if you did cut down and resize it to 7.62x39, it would run in a 7.62x39 AR if you replaced the bolt head with a 5.56 bolt head. I think you also don't fully understand that cutting down then resizing (oh, exactly like when I convert 223 to 300 BLK) works either. Jeez dude, before jumping into the koolaid and acting the fool, read what was written.

And since I just took a quick peek at some specs......if you still think it won't work. I'll fly you down here to AZ and we'll do it. But you got to put 5K cash on the table for when your'e wrong. I'll even rebarrel one of my AR's in 7.62x39. It'll be the easiest 5K I ever made

EricBu said:

I think you also don't fully understand that cutting down then resizing (oh, exactly like when I convert 223 to 300 BLK) works either.

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I think the problem here is you only understand half of it the base of the case is solid and can't just be resized larger the base of 5.56 is ~.070 inch smaller than the 7.62x39 chamber it's gonna split and you're gonna get gassed.

mavracer said:

I think the problem here is you only understand half of it the base of the case is solid and can't just be resized larger the base of 5.56 is ~.070 inch smaller than the 7.62x39 chamber it's gonna split and you're gonna get gassed.

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Take a fired case, then cut it down and size it with a 7.62x39 sizing die. Get back to me. Of course, you're welcome to throw your 5K on the table too. We can do this.

EricBu said:

Take a fired case, then cut it down and size it with a 7.62x39 sizing die. Get back to me. Of course, you're welcome to throw your 5K on the table too. We can do this.

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The body of a 7.62x39 case is BIGGER than a 5.56 NATO case a 7.62x39 sizing die won't touch or resize the body of a 5.56 NATO case.

mavracer said:

The body of a 7.62x39 case is BIGGER than a 5.56 NATO case a 7.62x39 sizing die won't touch or resize the body of a 5.56 NATO case.

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Right...so I take it you didn't actually take a fired case, cut, and resize it to see what you end up with? And of course, we haven't even brought fireforming into it yet. Anywhooo, you still don't seem willing to put 5K down on your statement that it is impossible. My position stands...I can cut down a 5.56 or .223 case, size it to 7.62x39, replace the bolt face in a 7.62x39 AR with a 5.56 or .223 bolt face, and make it run. I also think I could ***probably*** mod the 7.62x39 bolt face enough to make it run, but it would never run real 7.62x39 again. You gotta pay to see it though. Gonna be my Huckleberry?

EricBu said:

No, well.....unless you're gonna be running it in a 7.62x39 AR, and you swap the bolt out with a 5.56 bolt...then I imagine it would work. Starline 7.62x39 brass is cheap, buy once, cry once.

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Moot point. This is what the OP is really asking:

Shooter14854 said:

re-adjust my 300 blackout jig to cut to the proper length for 7.62x39 and resize the brass?

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It looks to me like what he really wants to do is make 300BLK out of 7.62x39mm. Since the body of the 7.62mm is larger than the body of the 5.56mm, it can potentially work but, he'd have to cut the case head down to use the same bolt head as for 5.56mm->300BLK. That's possible, too but, not recommended (waste of time and effort). Add to that, it means placing a whole lot of stress on the 7.62mm squeezing them down (base/rim diameter 0.447") to fit the 300BLK (base diameter 0.376"/rim diameter 0.378"). Again, can it be done? Sure, probably. A lathe and some sizing lube and you're off to the races. But, as you can see from the image (snatched it off Wikipedia) why would you?