CMMG conversion

gnmontey

gnmontey

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Anyone have issues with 223 after using a CMMG conversion? On Sunday my CQ311 turned into a bolt gun at a service rifle match. Every second round failing to achieve battery, and I ended up removing myself from the match. I had used the CMMG the previous Sat without issue and didn't clean the rifle after. Do these things tend to gum up the chamber or leave a nasty lead deposit that would affect 223 chambering?

On a side note, I changed out the hammer and hammer spring in order to get the CMMG to function. Can't see this beeing the issue but then again?

Thanks,

M
 
I heard the gas tube can get cruddy since .22 tends to burn quite dirty, so not enough gas is getting through to cycle the action. But I have been wrong occasionally though lol.
 
"What he said. Drop a few round of .223 through it after a .22 shoot."

Basically that is what I did, only a week apart. Shot 22 the prev Sat then tried shooting 223 Sunday 9 days later. Had 223 issues from the get go that would not go away. I persisted thru relay 1 by racking, shooting, then ejecting the next round manually etc etc. Caved during relay 2 after the first 5 rounds failed to function.
 
gnmontey said:
I had used the CMMG the previous Sat without issue and didn't clean the rifle after. Do these things tend to gum up the chamber or leave a nasty lead deposit that would affect 223 chambering?
Click to expand...

End your range session with some .223 to immediately clean out your gas tube.

I suspect your problem is the lack of cleaning after shooting .22LR. My kit is stainless and it emphasizes how dirty .22 LR is.

Give your rifle a good cleaning and you should be fine.
 
thats not what i said/ i said shoot .223s right after .22lr no space meaning after your done shooting .22lr change bolt and shoot .223 rem
 
gnmontey said:
"What he said. Drop a few round of .223 through it after a .22 shoot."

Basically that is what I did, only a week apart. Shot 22 the prev Sat then tried shooting 223 Sunday 9 days later. Had 223 issues from the get go that would not go away. I persisted thru relay 1 by racking, shooting, then ejecting the next round manually etc etc. Caved during relay 2 after the first 5 rounds failed to function.
Click to expand...

A week is a long time for gunk too become cement.
 
CMMG Conversion Heeeellllllppppp!!!!!

Gave it a good cleaning, lubed it, and it is still giving me grief. And, get this, the CMMG is now doing the same thing. It's as if the hammer is not reset by the fired round.

Chamber the first round, bang, then nothing, manually eject a live round, bang, then nothing, manually eject a live round....

Cycling well enough to strip a round, but not enough to reset the hammer (my guess)?

I did change out the hammer, and all was well for approx 50 rounds of 22lr.

Now both 22 and 223 are doing the same thing?

Heeeellllllppppp!!!!!
 
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Have you checked the gas rings on the bolt? If the gaps in the gas rings have lined up, you will have the short-stroke problem.

If this isn't the trouble, you may have to clean or replace your gas tube. It sounds as though not enough gas is getting back to the bolt carrier to fully cycle it.
 
Went to put the original hammer back in and discovered that the hammer pin had walked out of position. What prevents the hammer pin from walking?

Also, the original Norc hammer spring is a one legged afare and the Norc hammer pin appears to be larger in dia than the replacement I purchased (did not install). The pin detents are located differently as well?

This is all very bizzar!

Gonna put the new flat face hammer in again and try it tomorrow, keeping in mind to pay attention to the hammer pin.

On a side note, how does one determine failure to attain battery for an AR (I assumed this was the issue but now have second thoughts on the issue)?

Thanks,

M
 
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Your hammer has a spring in the center that's only job is to keep the pin in place. You will see it when it's disassembled. The spring should have two legs, they hold the trigger pin in place. You can however get anti walk pin kits. I've never found them necessary though. If you're dealing with Norinco, all bets are off. I have no idea what they do. I'm not sure they do sometimes.
 
browningautorifle said:
Your hammer has a spring in the center that's only job is to keep the pin in place.
Click to expand...

That explains the center detent on the replacement pin:redface:

In the end the displaced hammer pin was the source of all the issues. I shot both 223 and 22lr without a single problem what so ever this morning. However, the hammer pin was showing signs of walking. Will try the replacement pin which has the center detent and see what happens.

Looks like the Norc pin is 0.155 dia while the replacement pin is 0.153 dia. Is that enough of a difference to be concerned about?

Thanks guys!

M
 
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I would want as close a fit of pins as possible Monty.

Powerwagon, look at your trigger spring, it doesn't hold anything in place. It just operates the trigger. The legs of the hammer spring fold back and hold the trigger pin.
 
Hey guys, not trying to thread jack. I've been looking for a new rifle to shoot at the indoor range at the club I belong to. They only allow non-jacketed bullets, and I was thinking an AR with a CMMG kit would be nice (I've wanted an AR since I got my PAL).

Anyways, I've heard lead bullets will cause alot of fouling, and isn't recommended because of the gas system. If I'm firing off some rounds of 5.56 afterwards is this an issue? (related to the OP's original post and responses). Secondly, another plus with the indoor range is it's open late, so if I'm not able to go to the outside range to shoot off some 5.56, I would just half to give it a good cleaning?

Sorry if I've ventured a bit from the thread.
 
Does your range allow the use of plated bullets? They make plated pistol bullets, I would imagine you can get plated rifle bullets.

The CMMG runs like a top and is surprisingly accurate when all the ancilliary bits and pieces are in place correctly.
 
As far as I know, the president of the club said any sort of jacket is a no no.

Basically, a norc and the CMMG kit fits my budget as well as my needs, and I've heard the kit runs well. I'm just wondering if I pick up a box of non-jacketed 22lr if I'm going to run into troubles (especially if I can't shoot off any 5.56 afterwards)? Or would I need to go with a dedicated upper to avoid fouling up the gas system (down side would be spending outside of my budget)?
 
A dedicated 22 upper is not in my budget either. Ask your club about plated. If yes, then you are good to go 223 or 22. We shoot both lead and plated for Steel Challenge at my club. I can't say that 22 fouling will or will not eventually causes issues (but may be something that a bore snake would solve), my problem was the hammer pin from the get go.

M
 
Perfect, I'll ask him and see what he says. $900 is my absolute max, which a new norc and cmmg fit right into. I looked into some other options but I have a tough time justifying a restricted $500+ .22lr.

Sorry for the newb question, but I don't reload (yet). Is factory plated .223 available?
 
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