ACTUAL CONFIRMATION if CZ-527 7.62x39 Mags work for 300-221 rounds?

[este]

Kurtz,

That 7mm looks very cool. Thanks for sharing that.

A mandrel to press them sounds like a great idea. I wonder if it could be done cleanly or not? Seems to me that with the mag welded together it would be tough to properly press that. I'll think about that a bit though. It's definitely a good idea if it can be done. How far did you get?

Having seen it, do you think there is enough material for bend the feed lips on the x39 mag over to hold a whisper round properly?

[kurtz]

Originally Posted by este

A mandrel to press them sounds like a great idea. I wonder if it could be done cleanly or not?

sure, with a correctly made tool and enough pressure....

Originally Posted by este

Seems to me that with the mag welded together it would be tough to properly press that.

the weld shouldn't make a difference, the overlap next to the rib should help serve as a guide...

Originally Posted by este

How far did you get?

If I had a bunch of these mags to do I would of made it further along....since I only had four or five to do I just milled them....

disassemble a mag, hold it with the baseplate opening up....my plan was to make a two piece magazine holder that would surround the mag and keep the walls from pushing out...the tool/mandrel would be pushed in the mag from the baseplate opening with a hydraulic press...the tool would need to be stepped.......on either side of the rib would need to be the full mag opening width (to keep the tool centered in the mag body) and then step down to the new desired rib height...

I made some real rough tools out of hardwood and aluminum to do the same thing to 20 round straight AR mags to push the rib out for 300 Whisper loads (aluminum AR mag vs steel CZ mag, the CZ tools would probably need to be all steel) The AR mag tools worked good, so I would think the CZ tools would work as well....but for the AR it's pretty easy to de-rib PMAGS...

Originally Posted by este

Having seen it, do you think there is enough material for bend the feed lips on the x39 mag over to hold a whisper round properly?

Viewed from the top, the distance between the feed lips taper from .365 at the rear to .378 at the front....the lips could probably be squeezed together enough to hold a whisper case, but it'll fit pretty sloppy in the mag body....I haven't compared the seating depth of the two mags to see if there is a difference......I'm probably gonna stick with milling the .223 mags....

[este]

Well, 223 Mags it is then.

If you don't mind, I'm going to borrow your idea for pressing those out a bit. I think aluminum billet would work for the mag body, but probably steel for the tapered pressing piece.

FWIW, the 223 mag lips on my mag here are .325 at the bottom of the taper and .338 at the top. So, yea, .050 wouldn't be a ton to turn in, but it would be tough to get it at the right height.

[kurtz]

got around to pulling both rifles out of the safe at the same time....

the .223 mag is .475 wide...

the 7.62x39 mag is .517 wide...

[amafrank]

In my opinion pressing the ribs out is a lot more difficult and likely to damage the mag. All that metal has to go somewhere when you squish it. Its not likely to go back where it came from so your mag will end up rippled or too long or who knows....good idea but I don't think it will work reasonably without some heavy machinery. On the other hand, milling out the ribs and then soldering or brazing in patch plates would be pretty easy. In reality the patch plates don't have to be fitted to the slot (though thats easy to do) but can overlap the edges. If you mill them out wide so there is no flange left inside the mag you can solder the patch plates inside the mag too. It fills the hole so crap won't get inside but doesn't distort the mag body. A last suggestion here was done by a customer on one of the mags I modded for him. He put some clear tape over the slot, inside and out, to seal it while making it possible to see how many rounds were left through the clearly visible slot. Slot covered for dirt exclusion but round counter in place.

Hope that helps
Frank

[kurtz]

On the aluminum AR mags I pushed the ribs in about .070" each side, using a wood surround and aluminum press piece was all that was needed and they worked out fine.....no growth or warpage...

I believe JD modified some in a similar fashion using a wood push piece and hammering it in to open the mag up a little....the ones he supplied with my AR had the top 2" or so milled out

the steel cz mag, and the way the rib has a bevel surround is gonna be different....that's why I figured the steel surround would be needed to keep it from growing when pressed, much more pressure...but hey, if somebody can make aluminum work I'm not gonna throw water on their enthusiasm or experimenting....I think it would be neat if it works out....