What is the best way to break in the Hi Cap mags??

[gophernuts]

Just what it says. Any tips or advice. Somebody needs to figure out a polymer mag, like right now. These metal mags are horrible on the brass. Anyways, any input would be great. I'm speaking in reference to the 25 rounders.

[warped]

It was figured out already, however if you consider the huge investment and also the mindset change involved in getting a truly large company to do this then you realize why it did not already occur.

Dies alone could run into the millions.

Yet my metal mags have not messed up any brass.

[skyfish]

I feel your pain gopher, mine feed well. But about half of mine sit the the cartridges too high, so the bolt dents the shoulder. A little tweaking has helped. I have one 17(15 is all I try), it was the worst. If you shoot the whole mag you won't notice this. I also had to polish the ejector just a tad, that helped as well. Mine had that stovepipe problem, and the brass would get hung up by scraping the lower part of the chamber. I only loaded a little for this round, I do plan on going to a bushing die. That will prolong brass life as well.

I have looked at my 5.56 brass, and in general, ARs' don't pamper brass.

[gophernuts]

I hear ya for sure. I just wish the mags didn't suck quite so terribly, because they do. After some sanding on the follower it works a little bit better. I'm going to bead blast them and cerakote them and hopefully that will improve the lubricity a bit. Anybody every try doing that? I did it with a few .223 mags just to get uses to doing it and it worked amazingly well so I expect the same results.

[RangerRick]

I hear ya for sure. I just wish the mags didn't suck quite so terribly, because they do. After some sanding on the follower it works a little bit better. I'm going to bead blast them and cerakote them and hopefully that will improve the lubricity a bit. Anybody every try doing that? I did it with a few .223 mags just to get uses to doing it and it worked amazingly well so I expect the same results.

If you are getting cuts in your brass check to be sure you have M4 ramps and check the ramps and lug edges on the barrel extension for sharpness. Sometime, particularly on new guns sharp edges will slice brass. You can smooth them a little with a small file or dremel tool to fix it.

[pinzgauer]

Somebody needs to figure out a polymer mag, like right now.

Buy or borrow a P-Mag. Load it up with Grendel. Try 5, then 10, then 15. You'll see why this is easier said then done. Not that it's impossible, but will be very challenging. Hint: 5 works fine, 10 works, but is tight, 15 does not work, just bulges too much.

These metal mags are horrible on the brass.

Something is wrong. three different grendels, shooting 12+ 25 round C-prod mags bought at various times from 2008-late 2010. Just never had that problem.

If you are seeing scratches, it's most likely feed ramp edges or edges on the barrel extension. Very common.

If you are getting dents from the bolt/carrier something is wrong, I'd try a different lower and upper to try to fault isolate.

The small dent in the side of the case is due to ejection, and functions as a handy reload count indicator. (But has no other effect)

5.56 brass is usually beat up as well, especially in carbines. But fewer reload 5.56, so most do not notice.

[LR1955]

I feel your pain gopher, mine feed well. But about half of mine sit the the cartridges too high, so the bolt dents the shoulder. A little tweaking has helped. I have one 17(15 is all I try), it was the worst. If you shoot the whole mag you won't notice this. I also had to polish the ejector just a tad, that helped as well. Mine had that stovepipe problem, and the brass would get hung up by scraping the lower part of the chamber. I only loaded a little for this round, I do plan on going to a bushing die. That will prolong brass life as well.

I have looked at my 5.56 brass, and in general, ARs' don't pamper brass.

SF:

On the last forum there were pages written about how poorly C-Products magazines were made or worked. In this case, it was true. CP Grendel magazines are pretty poor and no one else seems interested in making them. This has gone on since the Grendel came out.

Of all the magazines CP produces (or produced) for the Grendel, according to the guys on the Grendel forum, the 17 round magazine was by far the worse. Very few guys had any that worked at all. I believe it was their design so I wouldn't bother with them. Chalk them up as a loss and buy the ten and 28 round magazines. Between these two magazines, the 28 round magazine is more dependable. Not saying you won't get one of five that still won't work but the 28 round ones are more dependable.

LR55

[StoneTower]

I have heard conflicting answers to these questions in the past. Can someone who has tried it please answer.

Can a small number of Grendel rounds feed reliably from a Magpul magazine?

How about the OAL in a Magpul magazine?

Would a cut down Magpul magazine weigh about the same or less than a C-products 10 round magazine?

I would like to cut some of the 20s down and make some for hunting.

I live in California so I have the 10 or less problem with new magazines anyway.

Thanks,

David

[VASCAR2]

I guess I'm lucky since I haven't had any issues with my C Products mags. I have the 25, 17, 10 and 5 round mags but use the 10 and 5 the most. I function tested all my mags with no issues but I bought these mags from 44.com last year so I figure they were made during some of the latter production runs.

[StoneTower]

I was very disappointed when I got some 5 round C-products magazines only to find out that they are the same body as the 10 rounders with more spring coils in the bottom of the magazine body so that they only hold 5 rounds. There is a noticeable weight difference between the 5 and the 10 rounders and since I live in a state that does not restrict the number of rounds that can be loaded while hunting, I just use the 10 rounders and load 5 or 6 rounds. I got the 5 rounders with the idea that If I was to go out of state hunting to a state that had a restriction, I would need them. It is nice to have the quick follow-up shot of an semi-auto, but I have never needed more than 3 rounds for a single animal. They are either dead or gone after the second shot.

[pinzgauer]

I have heard conflicting answers to these questions in the past. Can someone who has tried it please answer.

Can a small number of Grendel rounds feed reliably from a Magpul magazine?

Based on my testing with a 30 round pmag, yes. In my rifle, AA barrel / bolt. AA upper receiver. LMT lower. 5 was 100 percent reliable.

10 was reliable but tight in the magwell due to bulging. (Body as much as the lips)

15 was too bulged, and would malfunction.

I'm not sure I'd trust them for storage. But for range use they appear to be fine.

This is neither hard nor expensive to test.

How about the OAL in a Magpul magazine?

Did not measure, but 123 AMAX's at my normal COAL had plenty of clearance. I suspect if you are using VLSD's you may hit a snag

Would a cut down Magpul magazine weigh about the same or less than a C-products 10 round magazine?

Negligible difference, especially if it was cut down. You really worrying about mag weight???

I would like to cut some of the 20s down and make some for hunting.

I live in California so I have the 10 or less problem with new magazines anyway.

Not real sure how you'd cut down 30's. I've not tried 20's with Grendel. But you could sure block a 30. Maybe cut & solvent weld it?

[sneaky one]

Stone T. I had the same result with the 30-Pmg. as Pinz. The 20 Is the one I wanted to work, for hunting it's the right size, I;ve gotten it to function most of the time,, After reshaping the underside of the feed lips with a 7/16 th's diam. carbide Bit, like those ones you see at the h. ware store made of alum. oxide, that looks like stone. OAL seemed a bit short, so I filed a lil more clearance front and back inside to get to 2.245 max. Also flat file a bit,, the inner ribs down cuz of the wider bullet area, than 5.56. I tweaked the follower some too. I gave up on the project for now... Am thinking of epoxying the top half of a Grr. mag onto a Pmag lower. Maybe it would work,..... some other company needs to step up. I heard D & H was close to a deal.

[StoneTower]

For California use there are lots of guys cutting them down (for 5.56 use). I am not sure if it would be better to start with a 20 or a 30 to get it to work with the Grendel. I like the plastic idea and the fact that there are dust caps for Magpul mags is a plus too.

http://www.calguns.net/calgunforum/showthread.php?t=440743

[mtn_shooter]

I got 10 of the CP 25 round mags and they all work fine. I also have 4 of the 17 rounders, but mine are marked "6.8" (I assume either they're the same magazine, or the messed up the order), They work great, nonetheless. I also have a few 10 rounders that only hold 9 rounds but work fine. The only problem I had with my AR feeding was before I cut m4 ramps into the upper. That fixed everything. It's simple, wider case means the tip of the bullet is lower in the magazine, so your feed ramp needs to start lower.

[sneaky one]

Stone T.--- oops , forgot about the 5 rnd. poly. mag., that's in the Brownells catalog. It's a 7.62x39 unit. You should be able to hone the body/ shoulder area indifference to a Grr. case. size , under the front 1/2 of the mag. lips. Califonry legal. I am going to order 1 soon., to try out . They are about 13.00 ea. Brownells .com = free catalog.