CMMG AR-22 upper feeding issues...

[kidchill]

I have a Stag Arms AR with the CMMG dedicated 22 upper, not the conversion kit. I'm having serious problems with mis-feeds! I found this link here: http://www.ar15.com/forums/t_3_15/526872_How_to_make_your_AR_22_run_smoother_NOW_with_pictures.html&page=1 So, I brushed out the proximal end of the barrel as well as polished the feed ramp. Now, I forgot to get a polishing chemical, but I made that feed ramp damn near shine. Before these mods I was literally mis-feeding at least twice with 6 rounds in the mag (it was horrible). I'm now mis-feeding two to four times per 25 rounds. I love shooting plates with this gun, but having to fix the mis-feeds is totally killing the flow! I was trying to see what mags I have, as I've heard some are better then others, but I have the mags CMMG themselves make. I've heard good things about Black Dog mags, but seeing as how it's CMMG mags, I'm not sure it'll make much of a difference. I'm at the point where I"m almost ready to just sell the upper and buy an AR22 or 10/22 with a new stock and 25rnd banana mag. IDK, any pointers or ideas? Also, I've read that they seriously recommend NOT taking apart the bolt-carrier group as people end up damaging the rails and throw the spec off. I have NOT disassembled this, I've only removed the bolt carrier group and slid back to access the feed ramp. Also, I spent quite a bit of time getting the old lubricant off, and then oiling the rails, hoping this would reduce any friction...no luck. Any info is certainly appreciated!

 

[wally]

Do you only have one magazine? if not, do you have the problem with all mags?

What ammo? Remington Golden Bullet bulk pack is the only thing that has ever given feed problems in mine -- and its because too many of the rounds "fold" instead of climbing the ramp. They give this same problem in my Ruger MKII and 22/45 pistols.

I'd have suggested you call CMMG (or use their web site "contact us Email) before "polishing" anything.

If you've only got one mag, buy a Black Dog "metal lips" magazine to try.

Can you try another lower? Maybe the mag is not a good fit -- tolerance stack up, bad luck

 

[Fishbed77]

Do you only have one magazine? if not, do you have the problem with all mags?

This was my first thought as well. It sounds like a mag issue.

If not, call CMMG. Their CS is good and they'll take care of you.

ON a side note, my CMMG dedicated .22LR upper has been very reliable with a wide range of ammo (all HV). I have only used Black Dog mags (both steel and plastic feed lip versions), and they all work well for me.

 

[wally]

I didn't notice initially that the OP had a CMMG mag, these are very much like the Black Dog mags, but they have "fitting tabs" on the body where the bottom of the mag well will be that usually need to be filed a bit in order to get a good fit to the mag well. If he didn't do this they my not be seating fully.

Its pretty easy to miss this in the instructions that come with the conversion kit of upper.

The Black Dog mags seem sized small enough to fit everything and I've never had any issues with them when they seem "loose".

 

[kidchill]

"I'd have suggested you call CMMG (or use their web site "contact us Email) before "polishing" anything."
The link I posted contains a message directly from CMMG suggesting this modification...

"Its pretty easy to miss this in the instructions that come with the conversion kit of upper."
It's not a conversion kit, it's a complete upper.

"What ammo? Remington Golden Bullet bulk pack is the only thing that has ever given feed problems in mine -- and its because too many of the rounds "fold" instead of climbing the ramp."
I'm not sure of the type, I just finished off that box and chucked it, but it was Remington. I've also shot Winchester (hollow point/copper plated) and have the same results. I have a box of Eley Target that I haven't tried yet. I'm gonna give this a go this weekend.

"I was trying to see what mags I have, as I've heard some are better then others, but I have the mags CMMG themselves make."
I have 2 mags, both are CMMG, and both cause mis-feeds. I'm considering purchasing the Black Dogs to see if this helps. I would think CMMG mags would be the best, considering they're from the company that produces the upper. I think I'm gonna email CMMG and see what they say. I was just curious if anyone has heard of any other mods I could try. I've noticed two other things as well. I'm not sure how to articulate this, but when I insert a mag and then pull the hammer, I have to release it and make sure there's enough force coming forward or the portion of the assembly that I can see inside the dust cover doesn't return fully. There's a good 1/4 to 1/2 half inch gap there. I thought this could be overcome with a good cleaning and proper oiling, but it was still occurring. Also, I can't lock the chamber open. I'm not sure if this is just a design flaw, or if I maybe have a faulty bolt-assembly group. So, I'll email CMMG and see what they say. Reading that post, it sounds like some people have a lot of trouble, some have no trouble, and some of the ones that were having a lot of misfeeds were able to correct them with the mods. Fingers crossed I figure something out without having to ship it back!

 

[wally]

It's not a conversion kit, it's a complete upper.

Doesn't matter the CMMG mags have tabs on the bodies that may need to be filed down for a good fit in the mag well. If you didn't they may not be seating fully. Its easy to miss this in whatever instructions you got with it. Look on the sides of the rib at the back of the magazine.

These mags don't activate the bolt hold open, but the bolt will hang on the back of follower when empty and then move forward when the mag is removed. If your bolt is not going fully forward because the follower of the empty mag is rubbing the bottom of the bolt, your mags are probably not seating fully, the bolt should hang on the back of the follower when the mag is empty. You should not be able to cycle the bolt on an empty magazine if the bolt is forward when you insert it.


They make a gizmo for the lower and a more expensive magazine that activates it to use the normal AR bolt hold open -- I've never bothered with it, or seen the point.

 

[Fishbed77]

I've noticed two other things as well. I'm not sure how to articulate this, but when I insert a mag and then pull the hammer, I have to release it and make sure there's enough force coming forward or the portion of the assembly that I can see inside the dust cover doesn't return fully. There's a good 1/4 to 1/2 half inch gap there. I thought this could be overcome with a good cleaning and proper oiling, but it was still occurring. Also, I can't lock the chamber open. I'm not sure if this is just a design flaw, or if I maybe have a faulty bolt-assembly group.

Not sure what you mean by "pull the hammer." When you pull the charging handle back to chamber the first round, do not "ride" the bolt closed. Let it go so the full power of the recoil spring can chamber the round. The very first time loaded my CMMG upper, the bolt needed a little help to fully close, but it broke in very quickly.

There is no way to lock the bolt open with this upper, unless you install the optional bolt-hold-open adapter into the lower, and your mags have the special bolt-hold-open followers. The bolt will stay open after the last round is fired without these optional accessories, but will close immediately after you remove the empty mag.

 

[BluesDancer]

They make a gizmo for the lower and a more expensive magazine that activates it to use the normal AR bolt hold open -- I've never bothered with it, or seen the point.

+1

Hey there - I have exactly the same upper Fishbed77 has, and when trying it out the first time I used two different mags: 1-the CMMG mag that comes with it, and 2-Metal lip Black Dog X-form mags.

The CMMG mag seemed cheesy to me when I tried to run the gun with it. On the other hand, the Black Dog mags worked without a hitch. I junked the CMMG mag. No use keeping mags around that have issues (with exception of training for malfunction clearing).

Using black dog mags you will have to fully engage the charging handle to charge the weapon after loading the mag in the gun each time. Will the BOHA work this way? Nope. Chalk it up as the price of using cheap rimfire ammo in an AR15 and work around it.

 

[DoubleTapDrew]

What hammer do you have in your lower? I haven't closely inspected the CMMG dedicated upper but if it's anything like my conversion kit you have to have the non-notched hammer or the bolt will hang up often. It's a <$20 part and easy to change. Cured mine.
You wane the one on the left, not the right

 

[kidchill]

I emailed CMMG and told them everything that was happening and what I had done to the feed ramp. They said the most important mod is to use a drill and wire brush to really polish the proximal end of the barrel. So, I'm gonna give that a go. I did it by hand, but they said using a drill and really cleaning it up should help the issue. Honestly, I'm not totally convinced. I may just go ahead and order some Black Dog mags as well. Yah, I have the CMMG mags that hold the bolt open after the last round, which I too could care less about. When I say the bolt isn't fully closing, that's without a mag even in it. That's why I was wondering if it's a faulty bolt carrier group. I would think it should close all the way every time, especially after I lubed it up really well. So, I'll polish out the barrel and put some rounds through it this weekend, and then order the black dog mags and see what happens. I finally got accepted into the best shooting club in the area, and it's hella fun to shoot plates with that gun, so I'm hoping I can get it working more reliably. Also, for the hook to keep the bolt locked open, I'm not gonna worry about it. The only real reason it bothered me is cause when I'm at the range, if I lay my gun down, I like to keep it unloaded with the bolt locked open (for others to see they won't get shot if we're cold), but if I'm shooting this I'll just lay it in the case and close the lid. I'll probably be at the range for a while this weekend, my new glock should be in tomorrow, so I've got some shooting to do! Thanks for the info, and I'll report back as to what happens.

 

[Fishbed77]

When I say the bolt isn't fully closing, that's without a mag even in it. That's why I was wondering if it's a faulty bolt carrier group. I would think it should close all the way every time, especially after I lubed it up really well.

It should close.

Personally, I wouldn't bother with trying to polish anything. I'd send it back to CMMG and let them figure it out.

 

[wally]

It should close.

Personally, I wouldn't bother with trying to polish anything. I'd send it back to CMMG and let them figure it out.

Heck yes on a complete .22lr upper, uless like in post #9 your lower has a notched M16 hammer.

 

[happygeek]

Also, I've read that they seriously recommend NOT taking apart the bolt-carrier group as people end up damaging the rails and throw the spec off. I have NOT disassembled this, I've only removed the bolt carrier group and slid back to access the feed ramp.

I don't doubt they recommend that, but I take mine apart almost every time I clean it. I've found mine tends to run best when I take Q-tips to the notches on the side of the bolt where it rides on the receiver plate, wipe the receiver plate rails down real good, clean off the feed ramp while the barrel collar is out, and then re-oil the rails and the notches on the sides of the bolt real good.

Mine also prefers Federal Value Packs & Winchester. It HATED Remington ammo. I've had good luck with CMMG and Black Dog mags.

 

[kidchill]

So, here's an update. I got a drill and used a 22 wire brush, and then went back in with a 9mm wire brush to clean out the proximal end of the barrel. I also re-polished the feed ramp, and I used some Eley ammo. I probably had about 3 or 4 mags (fully loaded) that cycled great. Later on in the day I'd still have 1-2 jams per full mag. So, it's getting better. I think it's a combination of the drilling to the barrel and different ammo. I'm not sure how good that Eley ammo is, the projectile is black and there's a really weird smell when shooting it. So, I may just have to get some higher quality 22 rounds for that gun. I also noticed that there is quite a bit of play with the way the mag sits in the magwell. Further, I honestly think some of the issue is just breaking in the upper. I really hadn't put that many rounds through it prior to this weekend, but I probably put half a brick through it on Sunday. So, I'm on the fence about ordering some Black Dog mags, I'll probably just go ahead and order them. I think when I bought the CMMG mags that there was a wait on the Black Dogs (like 2-3weeks), so hopefully I don't have to wait too long. Question is, metal or plastic?

 

[wally]

I think when I bought the CMMG mags that there was a wait on the Black Dogs (like 2-3weeks), so hopefully I don't have to wait too long. Question is, metal or plastic?

I'd say get the metal lips but the X-form nylon lips can also be replaced if they get damaged. Midway had them in stock a few days ago.

 

[BoilerUP]

They might be hard to find right now...but try CCI 40gr Mini-Mag (round nose) or CCI AR Tactical. QUALITY high velocity ammo is your friend.

My CMMG Bravo conversion kit really absolutely hated Rem Golden Bullets & Thunderbolts, and Win Dynapoints. It does pretty well with Fed Automatch, but runs like a sewing machine with Mini-Mags, AR Tactical, and even CCI SV (now that it has 1500ish rounds through it).

 

[Fishbed77]

I think when I bought the CMMG mags that there was a wait on the Black Dogs (like 2-3weeks), so hopefully I don't have to wait too long. Question is, metal or plastic?

PSA always seems to have one or the other in stock. Either version works well for me.