New CMMG Evolution .22 magazine....WONDERFUL!!

The big Brown truck came today with a sample of the newest version of the .22 Evolution magazine. I took it down to the shop and loaded it with my "dummy" .22 rounds. (These are nice machined aluminum and are great for safely checking actions). I cycled the action as fast as I could. The rounds all loaded and ejected perfectly then, on the last round as it popped out.....the bolt locked back perfectly. Wow! OK, lets try that again to see if this is real. I did this five or six more times and just like clock work the bolt locked back on the last round each and every time.

CMMG....you got it!! I have a few of the first batch of these. The stiffer springs weren't ready at that time so CMMG fitted them with a softer spring but while it feed properly it was not stiff enough for the BHOA to function properly. No sweat, I just removed the BHOA and used the magazines without it in the rifle. The mags worked great with whatever I put in them. This new mag I just got has the stiffer spring in it and it works the BHOA like a dream! I love it! The nice part of this is that while the original (grey plastic) BHOA magazine was difficult to load this new Evolution mag loads easily. I wrote about this and posted pictures some time back. The the original magazine had to be designed around the old style mag body. This required an extra piece made into the follower that had to spring out and work the BHOA. This piece caused various issues if things were not just right. This new design Evolution mag started with a clean sheet of paper. This allowed CMMG to make the follower longer and it does not require the little pop-out piece to work the BHOA. This means you don't need so much spring force to properly work the BHOA. The result is the magazine we have all been waiting for...

OK CMMG, you have done it again! I know people have been waiting for this thing. I also know CMMG has been doing their best to get this thing done. I have my sample and I can tell you...its the Cat's @$$ and works like a charm. I want more....

got one to spare

how do we get a new spring :)

OMG please tell me we can start ordering 25rd long skin mags now! I have some older mags that need to be rebuilt for my CMMG upper ASAP!!

we will be getting them shipped out here really soon. i have a few thousand tops that just finished up. We approved the springs and are just waiting on the run to finish up. Cant wait to get these going.

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YES!!!

So we order this and this, and should be good to go?

As promising as this may sound, please test them with live ammo before proclaiming them as holy grail.

I have had several instances of mags feeding dummy rounds manually, yet failed miserably at the range.

Sure, these probably work, however, Murphys Law is a motherfucker.

I agree. And if there is a problem, believe me, I'll have it. My friends tell me I can break a ball bearing. Looks promising though.
Dave N

I have several of these magazines already and have been using them for some time. They did not have the stiffer spring however to work the BHOA. I have put hundreds of rounds through them and they have performed flawlessly. The only feature they were lacking was the right spring, stiff enough to work the BHOA. That new spring was the only piece that was missing from my setup. So, now with the spring the BHOA works, the final piece of the equation. Its strong enough to make the BHOA work but not still like the old style mags. Fact is when I first felt it it didn't seem so much stiffer than the first ones I got. so, I tried both the "original:" spring and the new stiffer spring in the rifle to see. The new spring works the BHOA just great. That is why I am stating it works find. Again, hundreds of rounds through this mag design without issue.

I will, however, be taking this magazine out for hundreds of more rounds to "verify" it works. I like to verify my firearms every chance I get...

Hundreds of rounds?

I have ~7.5k (total) through my 4 BDM mags with the only failures in the last 6.5k'ish having been monopoding on them causing a couple FTE's out of a 26 round mag.

I plan on buying 10 of these Gen 2 CMMG mags, but they have to be proven, that to me means thousands of rounds without malfunction like my BDM.

The only issue what so ever with the Gen ll mags has been the BHOA operation. Other than that, we have had excellent results with them.
I have a Gen 1 standard 15 round mag with about 10K through. It shouldn't have lastest this long, but I'm still using it.
Dave N

So...... I've read about clipping a coil or two from the rifles bolt catch spring, in order to to get the BHOA to work reliably with the older grey magazines.
Does CMMG install a lighter than normal spring in their rimfire lowers or a standard bolt catch spring?

I also read now that the new Evo magazines (that those of us in the unwashed masses don't have yet) have heavier springs (just approved) that will operate the BHOA reliably now. (alleged)

Is there going to be any combination of springs that will allow both the older grey and the new Evo mags to be used interchangeably without having to swap springs all the time?
I'm starting to wish I would have never purchased the grey mags now.

I just got my lower receiver back from the anodizer and it's ready to be assembled. It would be nice to know what kind of bolt catch spring I need to install, and only have to do it once. It would be even nicer to install a standard spring, to be compatible with a centerfire upper as well. But it the grey mags won't work with it....

That isn't always true. It depends on the depth of the bolt catch spring hole. That comes from the manufacturers spec.
The lowers that I have clipped springs on work fine with my 5,56 uppers.
You can always do what I do and don't worry about the BHOA. If I want the bolt locked back, I lock it back. I don't care if the bolt locks back on the last round fired.
Granted it should but I'm only going to allow so much aggrevation. The BHOA is the only part of the system that can be a potential problem.
To me, it's not worth the trouble until it can be assured to run without modifications. Just my feeling about the whole situation.

My favorite thing about the Gen ll mags is how reliable and how easy they are to load.
Dave N

I see that and I agree with you. Doesn't make me feel any better about buying a new upper and BHOA system that may, or may not work though. Especially when I already have a perfectly good Colt conversion that runs just fine, but just doesn't lock the bolt open. That was the whole point of my buying the CMMG system.

Oh well, my fault for drinking the Kool Aid. Lesson learned.

If it makes you feel better, I hand cycled my new Gen ll mag tonight with the Gen l and Gen ll BHOA. The bolt locked back.
But I have not been to the range yet.
Dave N

First, as for "Thousands of rounds" vrs "hundreds of rounds"...I don't keep track. I know that in the past season I have burnt up at least ten or twelve Federal Bulk packs (the 550 ones) but, while that was primarily in my CMMG rifle some of it went through a few other .22's I have. So, hundreds is just that...MANY hundreds. Now, I did not get the Evolution mags until back in the Summer so I can not document how many hundreds of those rounds went through those mags, but is considerable and probably at least several if not quite a few thousands. Don't keep a log book.

I have also run a lot of rounds through the original Black Dog mags. Of course they cracked and had to go back for replacement so I have backed off even using them any more. The new Evolution mags have the stainless steel feed lips and something tells me I won't be able to wear them out. There is NO comparison in the Evo mags and the Gen 1 mags. The new design is just on a different level. I have been very pleased with them in my guns. (Besides my CMMG uppers ––- two––-) I also use them with my Tac Sol uppers and my CMMG conversion kit in my 5.56 rifles. For me, they work fine with all of these. Now, I have not tried them with a Spikes upper as I don't have one of those. I was going to build one some time back but since I could never get the Spikes conversion to work consistently I saw no reason to invest the $600 it would have taken back then to have a complete ST-22 upper. I have not tried these with the Chiappa upper either...and you can figure out why.

I built my main .22 AR on some "bargain" parts I picked up a couple of years back. I have a very early production TNW billet upper and lower. After I got them I learned why they were so cheap. The TNW I got was a low serial number one, something like 000046 or something. Anyway, it had some fit issues with holes not machined right and parts that didn't fit. I had to do some hand work on it to make everything work just right. My BHO latch was STIFF and it didn't like the BHOA magazines at all. So, I clipped one coil off the spring. After that everything fell into place. Now this lower will work great with 5.56, the original grey CMMG .22 BHOA mags as well as the new Evolution magazines. The little bit of work I had to put into has rewarded me with a darn fine lower.

So...in my lower ALL the magazines function just fine. Its not like it works with one or the other, it just works. Some of my other lowers (my small sample of ten that I have in the safe) worked fine with the BHOA from the get-go. I really believe its the difference in the depth of the spring hole (man, do these "mil-spec" lower vary!) or the stiffness of the spring you use for the bolt latch, or maybe even its the length of the plunger in the hole. All I know is that with my assortment of "mil-spec" lowers there is a lot of variation. From my conversations with the designers of these systems they find the same is true; that is a LOT of variation in parts out there. Lets face it, how many people are making AR lowers? How many suppliers are there for springs, etc.? Frankly I am surprised that these rifles work as well as they do!

SO, based on all these inconsistencies I am more surprised that AR's work as well as they do, not that there are some issues at times. Of course if you are that poor soul that has the rifle that doesn't work properly you may see this differently. I have had to make "adjustments" to a few of my lowers for various reasons. This occurred with FCG's, parts kits for the lowers, adapting 9mm mag well's, and more. BTW, I have multiple lowers from a couple of companies, like RRA and they vary from each other! SO, even with parts from the same company you can run into variations. My BHOA parts will work in one of my RRA lowers but not the other. Go figure. (Haven't tried it in the third one yet.). A thing as simple as the tension of a spring can throw things out of whack. I know its frustrating but so is life at times.

I tried my Gen ll BHOA in three lowers. Worked perfectly in my Spikes lower. Worked in my original CMMG lower with 20K on it. Would not function in my new CMMG pistol lower. The mag is tighter which will make the BHOA tighter.
This is the issue as John pointed out. Different tolerances, even from the same manufacturer. It's the nature of the beast.
Dave N

Ugh! All these "versions" are a PITA. Is the "new Gen II" mag the grey one with the flipper follower, or the black Evo skeleton job?
I can't keep em straight.

Pick up a handful of receivers and measure their thickness (width). Chances are good that they will all be different. I don't think they can hammer out forgings to within .0005" of each other consistently. So when you are working on dimensions based from the center line of a forging, you will end up with different measurements from the center to the outer surfaces. I believe that is where the variance comes from in the depth of the hole you are speaking of. I recently finished machining a lower forging for this very build I'm working on. (Dedicated rimfire.) It's thickness varies slightly from front to rear as well. The next one I'm working on is several thousandths thinner than the first one.

So yes, I think you are on the right track.

The Gen ll and Evo are the same thing.

So we'll be able to buy them with the new springs soon? I've been waiting on them for awhile now..

Dustin, you have the patience of a saint.

sorry but i am still confused.....which one is the "NEW" GEN II and fits the M4 LEP upper i bought????


25 Round 22 Evolution Long Skin Mag <––––––- these are the Gen II

BHOA 25 Round Magazine for .22 Evolution

25 Round Magazine for .22 Long Rifle

eta: got your email....thanks for the info!

lol

My BHOA didn't work with the Gen ll mag and my new CMMG lower today. Got some adjusting to do.
The mag fed 100%
Dave N

I ran the New Mag yesterday. The upper/lower I had along seems to be all one way on the tolerances.
I'd swapped a spare bolt into the bolt assembly between range trips and it seemed to help some.
The bolt isn't one modded to work with the BHOA so I really didn't test for that function.. I fired 250 or
so rounds, loaded the mag to different levels, mainly because I lost count or what ever...
Didn't run Full Auto. One set of parts, Ron and I both forgot they were in another upper we didn't bring...


Here's a few videos. Various Round Counts in the mags. I'm popping small steel plates at about 25 yards:

You guys and your utube videos! I am lucky to post a picture, you make me look so........out of it.......

Hope all is well, Dave.

Ok, here is a question for you guys that are testing the new mags.

Between the older grey BHOA mags, and the new Gen II mags - which one has the most tension on the follower when the magazine is EMPTY?
I"m not asking about the ease of loading the mags. Just wondering which one puts the most spring force on the follower when it's at the top of the magazine?
That is.... IF there is any difference between them?

If the grey mags have less tension, I can begin working on finding a good spring rate for my bolt hold open now. If not, I'll have to wait for the back orders for the new mags to get rolling.

Just feeling the mags it would appear the new ones have LESS tension. Makes sense as the new follower is longer and comes straight up into the BHOA where the older style has to have that extra slider to go back and up and catch the BHOA.

Also the old style with the slider has a tendency to dig into the inside of the magazine body holding it up from sliding smoothly. The new design magazine is just a far better design. It should be, it started with a clean sheet of paper without the limitations of trying to make the old design work with new parts.

Ahhh, I was afraid of that. But it does make sense. I guess I'll just wait until the new mag arrives to work out the tension on the bolt catch. I have plenty of coil spring stock and I think I will just make one up with a lighter rate wire that will be full length, ratcher than shorten a stock spring. I only want to do this once before tapping in that roll pin for good, and just want to make sure it works with the lightest mag spring.

Thank you for the info.

Up date on the Evolution/Gen 2 long skin/whatever...magazine.

Range was closed for a time due to flooding but we are back in business again. I got to run this mag in my favorite rifle today to give it some more time to show itself. Well, just as before it worked GREAT. Each and ever time if fed the rifle 100% and then on the last round locked the bolt open without fail. I would load the mag full and it feed and did the last round hold open function just fine. After a while and getting tired of loading all those rounds I just started loading five or ten rounds each round. This kept my loading time down and let me do more last round tests on the mag. I did a lot of short mag loading today> That mag just kept on going.

As for those who had problems with these. My little .22 AR is my most used rifle. I built it out of a TNW billet upper and lower combo. I had problems with that lower and upper when I got them, they were out of spec and needed some hand work to get things right. At first my BHOA just refused to work. Finally I decided to do the bolt hold open latch spring mod. I cut one small coil off the return spring for the BHO latch. It still works fine for .223 and now it works GREAT with the .22 BHOA and the appropriate magazines.

I have had mixed luck with the BHOA on some of my rifles. Some, a minority, but still some just didn't want to work. After I did the clip on the spring for the latch my problems went away. Either the holes had not been drilled deeply enough or the springs were too long or two stiff. Whatever the problem a simple clip of the spring solved it. Now I am happy....my rifle works great with these mags.

Good to hear John. I've been doing more testing for basic function. Love these magazines.
May have a couple more get here today. They have a hefty feel of being very solid and
the basic function has been very good. Running semi or full auto they've been great.

Dave S

I'm going to try some reduced power bolt catch springs in mine.
Dave N

I tried two of the new short skin ten rounders last night in a brand new rig (CMMG guts with custom Douglas Match Bbl).

Ran about 300 rounds of assorted through them and saw only 2 which failed to clear the bolt, however, the main issue is the difficulty loading 10 rounds into the mag.

I was only able to load all 10 in once or twice. On one occasion, the drag of 10 caused me to use the forward assist for the first time.
Forced the testing to be run with 9 the rest of the time.

I'll get with CMMG later and see if they recommend tinkering with getting all 10 to fit.

Have to say that I didn't expect such good performance out of the new rig in general. Once the round count issue fixes, I will test it with the BHOA and see what comes.

I don't have any 10 rounders. I think they must be illegal in Kentucky...here you have to go BIG on your mags.....

I will say my "full sized" mags are quite easy to load and I have no complaints. Fact is, I just plain love the thing and want more.....

you can cut a half coil and the 10th rd will go right in.

forever, thanks for all the testing. we are noticing the need to deburr the concave area in the front inside of the tower. We are daily blasting away with these to make sure everyone has the same results you do

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Thanks, I'll try that and report back.

I ran in excess of 4000 rounds through my two 10rnd magazines last week (over a period of 3 days)...

I found issues in a couple of areas:

1. They rarely (Maybe once every 200-300 rounds?) locked back to the rear on the last round with the BHOA... Everyone keeps saying I need the higher strength spring, but I still dont see it anywhere that I can buy it...


2. After about 3500 rounds I started to have regular issues with the followers in the Gen 2 mags hanging up on something inside the follower channel. It was a total flash back to the Gen 1 magazines. I've yet to take them apart and see what the issue is, but It seemed like the follower was getting caught between the follower channel insert and the feed lip insert. My only solution was to pull the mag out and knock it against a table and then the issue went away. ––-I hope they just need a good cleaning, I WILL be reporting back soon

So, enough of the problems... Here's what has been working really well & that I really like about the new magazines:

1. I love I can look at the side of the magazine and see about how many rounds are remaining


2. The steel feed lips are showing very very little wear


3. When not running the BHOA, the magazines seem to do a decent job locking the bolt to the rear.


4. I like how well the magazines feed (with the exception of the follower issue noted above


5. The magazines just overall seems to be taking any abuse that's thrown at them. I dont try to abuse any of my gear, but stuff gets dropped... stuff gets stepped on... sometimes stuff gets thrown around... I like magazines that dont crack (guys who've shot a lot of AR-22's know what brands of magazines I'm talking about)

The 10 Round Core has a locating/assembly hole very close to
the rear of the follower channel. Like the Gen I, this is a weak
area that may get worn by the rear of the follower after a high
round count. You can see this pin hole through the right side of
the transparent core, about 1/8" above the skin's center divider.

If the channel wears through at this point, the follower can hang up there, just as
the Gen I's did. I'm surprised CMMG made the same design flaw twice.

My Gen II's are still running well and still locks back the bolt, probably because
I cut off a coil from the mag catch spring.

Ted

Ted, I read your posts about needing to add a .22LR relief hole to the bolt raceway insert for the upper receiver action blocks.

It's something I never thought of and might be why my old 22 upper was having windage problems. Anyways, thanks to your advice and a couple minutes with my drill press, that little problem's been resolved. Heck, it took me longer to figure out clearance problems with my drill press than it took to drill the hole. It works great!

Thanks again - It's insights like yours that keep me reading this site.

Sorry to hijack the thread. We will now resume our regularly scheduled programming.

-Raeth

You are welcome, but the idea was entirely someone else's. It may have been one of the Daves or John, or
another. I mentioned it because, like so many people who come here, I have made costly mistakes. If I can
keep another from screwing up, all the better.

Ted

Dave, I made up a new spring for mine with 1/2 the spring rate of a factory spring. (1-1/2 lbs. vs 3 lbs. to fully compress)

Pulling the charging handle back by hand (even s-l-o-w-l-y) will lock the bolt open every time using a grey BHOA magazine. (All I've got, until the rest of use start getting our pre-ordered mags.) I also had to knock off all the sharp edges on the BHOA adapter and the bolt catch with a stone before it would work at 100%. I also polished the surfaces of the bolt catch where it contacts the inside of the BHOA slot.

I found that the rearward pressure from the follower in the grey mag was forcing the sharp edge of the BHOA adapter into it's frame and hanging it up. Works MUCH better after removing those knife edges. For what it's worth......

The whole idea of the forum is to share ideas and experiences. I can't tell you just how much I have learned about procedures, parts, new products, and more from this site. The good, the bad, and the ugly all come out and hopefully everyone will benefit from the sharing. There are some smart people out there that really put some work into these things. You got to love it....

Thanks, makes perfect since. Like anything else, a fitted and polished part is much more apt to work smoothly. I'll give that a try.
Dave N

Yeah i cant wait to try some of these ideas :D

Dustin, I wish I lived closer to you so I could figure out what the issue is with your set up.
Dave N

Heh... My Gen 1 mags work great (when the follower doesn't stick)..


Anyways, I cleaned out the Gen 2 mags and I think the issue with the follower sticking was because of how flat out dirty they where. I hit the channel with some nice soap and water and it looks like we're good to go in that area. In the meantime, I think before I hit the range next time I'm going to pull my bolt catch spring and trim a couple coils off (something you'd suggested awhile back).

I mean, it's interesting... When firing, it almost never locks to the rear on the last round... but when i pull back on the charging handle, it will lock back then 80-90% of the time. I've tried a variety of ammo and no real luck.


Still... Everything else runs well... It's just the BHOA + Gen2 mags... The BHOA + Gen1 mags always lock back on the last round (but have that issue with the follower getting stuck).

So is the latest batch of the Gen2 BHOA mags still in it's testing stages? Any new updates on how they're holding up?

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