SOLVED/FIXED-------CMMG AR-22 bolt kit= JAM-O-Matic

[shadow65]

Sounds like a mag issue. Depending on what CMMG mag you have, it could be the feed lips or in the Evolution mags, the insert that the rounds fit in. Some would not feed 40 gr. But several of those mags had issues.
I would get the Black Dog mags.

Something else to check is any fore and aft movement of the bcg.
As stated, the Taccom pressure plug will limit this, putting forward pressure against the rear of the BCG. Use it with a buffer and spring.

Is the bolt sliding on the rail with no hanging?

What generation CMMG BCG is it?

Dave N

[Trgt]

What gen are they and are they plastic or metal lip?

His latest are Gen x (4). I have a suspicion its a mag issue.

The SIG ones are plastic feed lip, don't know generation, they have follower that gives pseudo bolt hold open by jamming into BCG after the last round.

The Blackdog direct ones are stainless feed lip ( XF-10BL-SS - X-Form Magazine- 10 Round with Stainless Steel Feed Lip ), also don't know generation, but I believe these were among last of Generation 3 they were selling -- I think I remember seeing a Gen 4 also being sold at the same time.

FWIW, I don't believe either of these activate CMMG's B.H.O.A. - that was a PIA in my opinion. Gun store gave to me with the SIG mags, I tried for way longer than I care to admit to make it work until I found out my mags wouldn't activate it when empty, so returned the BHOA. At the time I thing there was a special mag you had to buy, that isn't sold anymore (Evolution Mag?). Now I think there is just a special follower kit to retrofit your mags for the BHOA.

[shadow65]

I have no experience with the Sig mags. Not sure they are compatible but maybe.

Some of the BDM steel feed lips mags had tolerance issues. Contact Black Dog. They will send you replacement feed lips.

CMMG just released the new, one piece BHOA mags. I've not tried them.
They are available in 10 round.

I highly recommend the Taccom Pressure plug. It cures many issues but I still think yours relates to mags or a combination of the BCG moving and mag issues.

If you have the ist generation stainless CMMG BCG, in my opinion, it was the most trouble free. They newer ones with the brass insert are weak.

Even though I'm not working with CMMG any more, I'll do my best to get you running.

Dave N

[randomBytes]

I've been having trouble with my CMMG .22 upper of late too.

Ran really well until quite recently - I built a new lower since the previous one got a .223 upper a BB, and a Geissele DMR trigger.

The new lower has a Geissele SSA, though originally it had an ALG QMS trigger.

The problem is light strikes - failure to ignite the primers.
Its gotten so bad I'm lucky if I can get 3 shots off in a row - makes it tricky when running against the clock ;-)

A friend has a very similar upper, and we've exchanged various bits.

His upper runs fine on my lower.

My upper runs fine on his lower.

His bolt runs fine in my gun and my bolt runs fine in his.

I tried the pressure plug - didn't help.

Tried another firing pin - didn't help.

It does seem that the bolt isn't always going into battery, and there's signs of the hammer striking the lower part of the bolt (eg. when not in battery).
There were two sets of marks - wider from the mil-spec trigger and narrower from the SSA.

My next experiment is a little plug of plastic to compress the recoil spring a bit more - if the gun cycles (no bet), that should help push it into battery.

[problemchild]

UPDATE***********

Took it back to AB cerritos and they stuck it in their gun and fired off two mags with no issues. It might be my lower in conjunction with the cmmg mag?? Maybe tolerance stacking??

The guy at AB said you can adjust the mag inside the ar-15 adapter it sits in. So I might first try the kit in one or two of my other AR's and if it works I will just use those AR's. If not i will adjust the mag up/down to see if it works better.

The "smith" at AB said it looked like the jammed round I gave him from the range was sticking into the top of the chamber and slicing the nose.

I am still going to order one of the new x mags from BD but I will also try and run my other rifles.

I will report back in a few days. I wish I had a bullet trap to test it in........

[shadow65]

If you have the grey mags, there are two tabs on the rear rib of the mag that need sanding to adjust for fit in the mag well. I adjust mine to "just before drop free."
Some after market triggers can be a problem. These were designed for mil spec hammers.
Also, make sure the bolt is not dragging on the bolt catch. Seen that a few times.

Dave N

[Jimi Jah]

I use Ciener bolts. My older one is well broken in and will shoot the Ciener metal 10 round mag, the Black Dogs and the Black Dog made Sig 10 rounders.

My wife's new 14.7" billet will not shoot the Sig mags at all, jams up or FTE completely. The only operational difference is those mags, they are touchy about those. I'm buying more Black Dog's, the safest route.

[problemchild]

I use Ciener bolts. My older one is well broken in and will shoot the Ciener metal 10 round mag, the Black Dogs and the Black Dog made Sig 10 rounders.

My wife's new 14.7" billet will not shoot the Sig mags at all, jams up or FTE completely. The only operational difference is those mags, they are touchy about those. I'm buying more Black Dog's, the safest route.

Im thinking its the mags as well. I noticed that the mag sometimes holds the nose of the loaded round up at a 12' angle and other times down and level. The "smith" said it should be level or it will cause a jam.

[njineermike]

Im thinking its the mags as well. I noticed that the mag sometimes holds the nose of the loaded round up at a 12' angle and other times down and level. The "smith" said it should be level or it will cause a jam.

That grey CMMG mag sucks. I had to file down the nubs on mine to get it out of the magwell, and it still sticks half the time.

[shadow65]

Black Dog X mags are the way to go in my opinion.

If you want last round bolt lock back, get the Boonie mag adapter and S & W mags. It actually works.

Dave N

[lgm118icbm]

I have had *several* issues with my CMMG. It took nearly two years of parts flying across the country to get it working.

1. The old plastic body mags suck. They look cool and even worked for a while but the plastic feed lips wear out quickly (like 500 rounds). The new Evo mags aren't much better but at least they work. I've found that they are very picky in how you load them. The rounds have to be pushed down evenly as you load them.
2. The feed ramp is a bit too aggressive and can cause the front of the rounds to flip up and jam into the top of the chamber. I filed it down, profiled and polished it = problem solved.
3. My firing pin broke after ~700 rounds.
4. The broken firing pin mushroomed the chamber rim (really soft steel)
5. The BHOA is a worthless novelty. Even after I sent the rifle to CMMG and they "tuned" it, it still only works maybe 30% of the time.
6. The forward assist is also a worthless novelty. I've been through 3 that broke and I gave up after a while and threw it away. They only last ~300 rounds before the roll pin that holds it in place shears off.

[AR22]

It does sound like you have a mag issue. I however have never had a problem with the Older Grey CMMG mags or the Evolution ones with any ammo brand..

CMMG makes the best stuff in the Industry as far as .22 related conversions and uppers..

I hear the Blackdog mags are great, but the only ones we own from them are the 50 round drums. They run flawless, so I would expect the same quality in their 25 rounders too..
.

Needless to say my CMMGs run flawless. Yours will too I am confident of that..They are the Best Company going, for the .22 stuff. Great service if you happen to need it too..

[problemchild]

Preliminary test seem that Back Dog mags SOLVED the issue.

I loaded both new mags with 10rds each (cmmg mag would only hold 9) and then fed the rounds through by hand. Both mags fed all 10 rds with NO issue.

Well see how it shoots but I can say the BD mags are awesome and the cmmg mag sucks. BD said cmmg used to buy their mags and then started making the mags themselves copying cmmg mags. Seems cmmg screwed up bad. Not happy with cmmg crap mags at all.

They should reimburse me for ammo, gas, postage for return and range fees.

[AR22]

Hope you got it going. To ask for gas money, range fees and ammo money is a little far fetched. I am sure they will get a functioning magazine to you if the mag is the problem..They are a excellent customer service oriented company...But they nor any Company in existence today is going to meet those demands for gas money, range fees and ammo.

You ask for alot. Not even Walmart will give you the deal you are asking for

[Jimi Jah]

I use two Ciener bolts, one for my wife's AR. Polishing the rails does make them slide better as does some Slip 2000 EWL. So far, so good.

I noticed Back Dog also sells firing pins and extractors.

Question: Is there a block diagram or instructions on how to disassemble the bolt to change those parts?