CMMG MK 47 Mixed Results

[m4brian]

I know its a shocker, but my new 8" MK 47 was not 100% on its first trip.



It shoots nice and the brake is pretty good. Its a BLASTER.



ALL AK mags fit, but all don't function.



It SEEMS to have good accuracy potential, and that needs proofing.



Fit and finish are really upscale. I know this doesn't matter if its a jamomatic.



Reliability: ME THINKS, with PMags. PSA Plastic, and the cheap bulgy reinforced lip mags, it MAY be 100%.



First rounds - started to jam, then I had bolt lock and mortaring AFTER rounds complete. A few more rounds, and it started to run with all mags.



THEN it would NOT FEED the first round from Hungarian steel or even US Palm. IT doesn't like steel. I was NOT feeling good about laying out the fee for this garbage. (I'm sure I'll take heat for trying).



watched this vid: https://news.aroutfitting.com/2018/0...le-mag-tweaks/



and read this: https://gunmagwarehouse.com/blog/top...e-cmmg-mutant/



Then I noticed that the feed lips of Pmags and the cheap bulgies are DIFFERENT and longer than steel surplus. I guess it does make sense and why so many seem to have mutant problems, but I THINK that if I stick to Pmags and the cheap bulgies (and maybe the PSA Plastic) I'll be fine.



The basic problem is that because of the extended space between the mag lips and AR chamber, the rounds tend to nose up if the geometry of the mag lips is not just so. OK - sucks that I cannot run ANY AK mag. But there it is.



I still like the gun and having a continuous rail and better accuracy and trigger potential is nice. And... its pretty cool. Mags do lock nicely with VERY little or no wobble. While she heats up, its not that bad and there is not GB or sling lopp to torch you.

[yoni]

I sort of feel your pain, my PTR 32 will only feed reliably on Bulgarian mags.

My Zastava feeds with everything .

[m4brian]

I think ALL mutants are partial to Pmags: https://www.youtube.com/watch?v=TVmyrzWfQrM

[uffdaphil]

My 10” MK47 Banshee is the same. No probs with Magpul. No joy with metal. It’s fine though. I have about equal numbers of each and dedicate metal to the AKM.

[m4brian]

I'm running tests now. It seems that if you can load it you can shoot it - IOW - If the first round loads its OK. I learned at the range that the dud mags won't even load the first round and its a nose up problem. So now i will run snap cap tests on my mags. I seem to have a Chinese mag handy that might work, and the cheap Bulgies seem OK, but I am stocking on PMags and they will be dedicated to the MK 47 - they do look right in this gun, but not in an AK - just me.

Nice fit means nothing in this gun. Must test.

Another thing - much is made (by CMMG and the 'test' crowd) about how thin the bolt head is on 7.62x39 ARs, and how that can/does lead to breakage? Is there evidence for this?

[georgeib]

I'm running tests now. It seems that if you can load it you can shoot it - IOW - If the first round loads its OK. I learned at the range that the dud mags won't even load the first round and its a nose up problem. So now i will run snap cap tests on my mags. I seem to have a Chinese mag handy that might work, and the cheap Bulgies seem OK, but I am stocking on PMags and they will be dedicated to the MK 47 - they do look right in this gun, but not in an AK - just me.

Nice fit means nothing in this gun. Must test.

Another thing - much is made (by CMMG and the 'test' crowd) about how thin the bolt head is on 7.62x39 ARs, and how that can/does lead to breakage? Is there evidence for this?

I was reading a few years ago that 7.62x39 AR bolts were failing at 1000-1500 rounds. I seem to recall seeing some pics.

[Bret]

All else being equal, it logically makes sense that 7.62x39 AR15 bolts would be weaker than their 5.56x45 counterparts. That said, I have not heard such chatter since 7.62x39 AR15's became popular. I don't know of anyone performing a torture test. Even if they are weaker, is it really that much of an issue if one breaks? 7.62x39 AR15 bolts are cheap. Not that I'm suggesting one for actual duty use, but I have no issues running my M16 with a 7.62x39 upper half.

Regarding the CMMG MK47 not playing nice with some AK47 magazines, I think that a rifle that's supposed to take AK47 magazines that won't run with actual military grade AK47 magazines is a failure. In my opinion, it's less desirable than having to use 7.62x39 AR15 magazines in a 7.62x39 chambered AR15.

[m4brian]

All else being equal, it logically makes sense that 7.62x39 AR15 bolts would be weaker than their 5.56x45 counterparts. That said, I have not heard such chatter since 7.62x39 AR15's became popular. I don't know of anyone performing a torture test. Even if they are weaker, is it really that much of an issue if one breaks? 7.62x39 AR15 bolts are cheap. Not that I'm suggesting one for actual duty use, but I have no issues running my M16 with a 7.62x39 upper half.

Regarding the CMMG MK47 not playing nice with some AK47 magazines, I think that a rifle that's supposed to take AK47 magazines that won't run with actual military grade AK47 magazines is a failure. In my opinion, it's less desirable than having to use 7.62x39 AR15 magazines in a 7.62x39 chambered AR15.

I think having the beefier bolt is a good feature and seems to make sense, but again, wish I had done more research - e.g. - you can get a Wolf Pack and have a charging handle that beats all.

While I wish I had known more about the AK mag issue, I am content with Magpuls which are way more durable than any AR mags. I also think Chinese steel works in this gun as well as the cheap Bulgy mags which are very solid. I am glad I did not 'invest' in Circle 10s years ago after seeing them fail a drop test in a VZ 58 test (comparison). MP are tough enough.

I get your point about AR mags and bolts though - its likely a better setup than I would have first thought and replacing bolts/mags is a feature of the AR system. CMMG bolts are expensive.

[m4brian]

There is ONE thing that surprised me - I now have a USE for AK mags with NO metal in the tab area. While I've not heard it is a real problem, the AR was NOT made for an AK magwell, and the aluminum lower is more prone to wear with steel tabbed/reinforced mags. I get that good ones have a steel pin up front to mitigate this, but the rear lockup in part puts steel against SOME Aluminum. So... using all plastic mags eliminates this and they are cheap. I have plenty for serious use.