CMMG upper...help

[B!ngo]

What's wrong with using a .22LR CMMG upper with a poly lower. I purchased the complete (w/butt stock) lower for $109.00 two months ago, and just found out that CMMG has shipped my left handed Revo upper today (!). Very excited. I thought I would just mate them and be happy with fun, low-cost shooting. Is this not a good/dependable config?
And if the upper is specifically designed for .22lr, is that little insert part useful?
Thx,
B

[green grunt]

range report with the Taccom kit in place.

1st off...I thought the firing pin was a bit loose fitting , called the Taccom dealer and asked a few questions , he took the time to explain all to me...sounded good , so off to the range I went...

winchester 36grn....still had a few light strikes , much less then before the kit

federal lightning 40grn....still a few light strikes

cci velocitors.....100% (before the kit it was maybe 50%)

Rem golden 36grn (the 525 bulk packs)....almost 100% with only a few light strikes , out of 300+ rounds I had only 7 light strikes and all but one went bang when tried again..

I have to give the kit a big thumbs up

I ordered the complete kit , and belive it was woth every penny spent ....

thanks to all that refered me to the TACCOM kit , guess now I'll need to stock up on more ammo (the good ol' 525 bulk pack seem to work best)

[shadow65]

Good luck getting this resolved. I have had nothing but problems with my CMMG rifle and even worse luck with their "customer service" staff.

It wasn't always that way. Sorry they are giving you problems. I would help but I'm kinda on the outside now.

The TACCOM Reliability Kit will improve any Atchison type conversion or dedicated bolt.
Dave N

[lgm118icbm]

Good luck getting this resolved. I have had nothing but problems with my CMMG rifle and even worse luck with their "customer service" staff.

[NorCalDustin]

i have a ccmg upper on a NFA lower i havent shot yet....should i get the plug..should i expect some problems??

You need to shoot it first... Though, i will say... The kit is worth while IMHO.

[onegtalon]

Only way to know is to shoot it first. The kit IS cheap so it wouldn't hurt anyway IMO.


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OneGtalon

[ninjawho?]

i have a ccmg upper on a NFA lower i havent shot yet....should i get the plug..should i expect some problems??

[green grunt]

Thank You Sir , I already ordered a complete kit , good to know the info given by others is spot on , its a nice upper and I like how it shoots (good groups at 25yds!)

looking forward to giving it a good run when the parts show up.

Thanks to all for the help/info..............range report coming soon...

[shadow65]

Most likely is CMMG has too much head space on the bolt.
This is nothing new.
The TACCOM Reliability Kit will solve a lot of issues with light strikes and feeding.
The TACCOM Firing pin is slightly longer, comes with shims to adjust length, and is has a smaller, angled tip for more reliable ignition. It's also hardened so much less likely to break.
The Extreme extractor has a better angle on it and gives better, more consistent extraction to make upo for the excessive head space on the bolt.
The Pressure Plug keeps pressure against the rear of the action to give 0 movement under recoil which can absorb energy from the hammer strike resulting in light strikes.
It does need to be used with a buffer and spring.
This is the best up grade I have tested for solving the Atchison type conversions issues.
I have one if you need it.
Dave N

[green grunt]

thanks to all for the help and info .

[sdallace]

Make sure to put a tiny drop of lube in the extractor pin? Mine wasn't closing completely*cuz crud got into it. So it would have light strikes

[onegtalon]

Taccom reliability kit is your best bet. For one for my CMMG dedicated and all the problems went away.


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OneGtalon

[pennys dad]

Hi

I had the same issue a few weeks back, I was lucky to have 2 other uppers handy.
I change uppers, mags, entire bolt assemblies, springs, firing pins.
I also rechecked my lower assembly and buffer spring.

End result was firing pin. Switching the pin solved 99% of all light strikes.
I changed the firing pin to one that was consistent and the rifle fired.
I still get one light strike every 50 to 100 so I feel additionally a stiffer buffer spring and H2 buffer are needed for adjustable stocks but for the A2 stock the defaults work fine.

[green grunt]

Thanks much for the link

when I pull the CH all the way back hard... I get a bit of movement of the front collier (1/8" maybe)....the pressure plug may be the fix I need...

[paintballdad]

Here's the linK to the Pressure Plug.

I sent my upper back to CMMG for them to check out. According to the repair order, the light strike misfires was due to the cartridge was not seating all the way in the chamber. They "buzzed" the chamber to smooth it out and cleaned & checked the firing pin. I ordered and installed the pressure plug as insurance against light strike misfires. The upper has been 100% reliable since.