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View Full Version : New CMMG Upper... Much Better!!


thunderbolt
01-15-2011, 2:45 PM
Last week I purchased a complete CMMG .22 upper w/ a phosphated bolt for my AR rifle along with three 10 rnd mags. After a good cleaning and buffing I took it out to the range this week but was frustrated by its performance. I wrestled through almost 400 rnds using three different brands of ammo. On average it would fail to fire at least 3 rnds out of the 10, regardless of magazine, and would almost always fail to extract that round. Once I did extract the round I could see that the firing pin had struck it. It would also stove pipe fairly regularly as well as failing to eject a spent round causing a jam. On a couple of occasions the spent shell would get lodged above the bolt against the charging handle and a complete disassembly was required. It never did fire a complete mag without some problem.

I have read that these uppers may require a "break-in period" and I was wondering if this kind of operation is normal. I gave it a super cleaning after I got back and I was planning to take it out again to see if I could get it to run smoother but I haven't had the chance. I'm actually kinda pissed about this. I expected some rough operation until I broke it in but this is ridiculous. Any help?

97F1504RAD
01-15-2011, 2:49 PM
What kind of ammo are you using?

I would use nothing but CCI Mini Mags for break in and then after that see how things go.

NorCalDustin
01-15-2011, 3:09 PM
1) The breakin period is the first 200rnds minimum..

2) What kind of ammo are you using?


I have one with the Stainless Steel bolt/Barrel Collar, Forward Assist Adapter, and Bolt Hold Open... I've put over THOUSANDS of rounds through it in the last 3-4 months... When using quality ammo, I only ever had 3 malfunctions. When using Remington GB's (CMMG DOES NOT recommend you run GB's) I get the occasional FTF (Bad round)...

Mine eat's everything.

NorCalDustin
01-15-2011, 3:11 PM
Also do you have a notched hammer?

thunderbolt
01-15-2011, 3:24 PM
I was using CCI mini mags (only had 50 of em though), Federal bulk 36gr HP copper and some 40gr lead "match grade" stuff that I can't seem to remember the brand right now (comes in a tan 350 rnd box). I never use Remington ammo...

My hammer is NOT notched.

This is gonna sound like a stupid question but if the break-in period is 200 rnds have I blown it?

I sold off my GSG-5 which ate everything for this and now I'm...grrr.

EDIT: The other ammo is Federal Target Grade 40gr lead.

Carsgunsandchics
01-15-2011, 5:20 PM
How about kicking back in front of the tv and hand cycling the bold a few hundred times? It sounds like everything is still real tight and with new coatings in the wear areas causing binding. Throw some oil in it where the bolt rides and cycle the bejeeses till it marks its wear pattern, once you get that it will start to feel smoother.
On mine the phosphate finish on the rails was causing major problems, and once the wear pattern ate thru it, I have not had a single problem.

NorCalDustin
01-15-2011, 5:49 PM
I was using CCI mini mags (only had 50 of em though), Federal bulk 36gr HP copper and some 40gr lead "match grade" stuff that I can't seem to remember the brand right now (comes in a tan 350 rnd box). I never use Remington ammo...

As far as I know my hammer isn't notched but I'll check again when I get home.

This is gonna sound like a stupid question but if the break-in period is 200 rnds have I blown it?

I sold off my GSG-5 which ate everything for this and now I'm...grrr.

Probably... I would contact CMMG... IIRC, Dude's name is Taz... He's a wiz with these upper's... They WILL take care of you.

It sounds like to me though that it just needs more break-in.

shadow65
01-15-2011, 6:35 PM
This is certainly not normal. I do know a few bad extractors got through. I've only ran across two, and as luck would have it, I have one. Better me than a customer.

Some minor break in with the parkerized kits is necessary but you should not be having those problems. These kits are made to run out of the box. Plug and play.
Did you take it apart? I ask because if you do not have experience taking it apart, the rails can get out of spec, which will cause cycling problems.

Another thing to do is buzz the chamber.
Use a bronze .22 bore brush in a couple sections of G.I. cleaning rod. Chuck it in a drill. Put some oil on the brush and run it in and out of the chamber until warm. This gets the crud out and smooths the chamber.

If you continue to have problems, IM me or call CMMG. We will get you running.
Sorry for the problems.
Dave

thunderbolt
01-15-2011, 6:53 PM
Did you take it apart? I ask because if you do not have experience taking it apart, the rails can get out of spec, which will cause cycling problems.

The farthest I took the bolt apart was removing the firing pin and cleaning the channel. Is it normal that the firing pin hits the round at an angle?

shadow65
01-16-2011, 6:55 AM
What do you mean at an angle?
Are the rounds sticking in the chamber?
Dave

thunderbolt
01-16-2011, 7:42 AM
The way the firing pin sits in the channel (with the groove that the retaining pin fits in I'm assuming that's how it sits in there) causes the firing pin to strike the round at an almost 40 degree angle. Basicly it's not squared with the bolt face. If it's suppose to be square I haven't found a way to make it so.

If I cycle a mag without firing none of the rounds stick but I've had to pry many rounds out with a small screwdriver (no damage to the rifle).

I'm headed to the range to try some different ammo and to see if I can get it to run.

Arteel
01-16-2011, 10:38 AM
If you still can't get it figured out, let me know. I'd be more than happy to meet you at the range to see whats wrong with it. I've been through two of these uppers which both displayed similar issues you are having. I managed to get them working perfectly after some tweaking. If you haven't already, pick up some lightened hammer and trigger springs from JP.

shadow65
01-16-2011, 11:16 AM
It's a great jesture for you to offer a hand getting him running. Good to see in the Firearms Community.:)

Again guys, there should be no lasting issues with these kits after break in.
I use my uppers and kits with no changes to the lowers.
I use my same lowers for 5.56.
That is what they were designed to do.

JP springs will make the trigger lighter but should not be needed for the kit to work. If they do, then there is friction some where slowing the cycling down.

We will be sending a call tag to thunderbolt and replacing the kit.


Dave

Arteel
01-16-2011, 11:26 AM
It's a great jesture for you to offer a hand getting him running. Good to see in the Firearms Community.:)

I'm just trying to return the many hands I've been offered on here!

Again guys, there should be no lasting issues with these kits after break in.
I use my uppers and kits with no changes to the lowers.
I use my same lowers for 5.56.
That is what they were designed to do.

JP springs will make the trigger lighter but should not be needed for the kit to work. If they do, then there is friction some where slowing the cycling down.

We will be sending a call tag to thunderbolt and replacing the kit.

Dave


Very cool of you guys. Looks like he's in good hands.

thunderbolt
02-17-2011, 8:54 AM
Got my upper back last night but wouldn't you know it's pouring rain. The frustration continues...

But the upper looks good. I had them upgrade the bolt and collar to stainless steel so we'll see how it runs. I have high hopes. Maybe I'll go out after all...

shadow65
02-17-2011, 10:44 AM
I only use one drop of oil per rail.
Make sure you buzz the chamber. One of the best things you can do to insure easy feeding and extraction.
Dave

uxo2
02-17-2011, 10:49 AM
Also do you have a notched hammer?

And this will will help too..
JP yellow springs.
http://www.riflegear.com/p-717-jp-reduced-power-spring-kit.aspx

NorCalDustin
02-17-2011, 10:52 AM
Got my upper back last night but wouldn't you know it's pouring rain. The frustration continues...

But the upper looks good. I had them upgrade the bolt and collar to stainless steel so we'll see how it runs. I have high hopes. Maybe I'll go out after all...
Consider heading to Cordova Shooting Center... They have all covered shooting positions.

Hopefully its nice this weekend!


I only use one drop of oil per rail.
Make sure you buzz the chamber. One of the best things you can do to insure easy feeding and extraction.
Dave
Good advice!

r1ghtw1ng
02-17-2011, 2:45 PM
Perhaps try this: Reduced Power Trigger Spring Set.

http://www.pkfirearms.com/Match_Triggers/35/c

For $8, it might be a good investment into more reliable operation. Sometimes the blowback of the 22LR round is not enough to reliably reset the standard power AR-15 trigger spring.

shadow65
02-17-2011, 4:13 PM
Don't change anything until you shoot it.
I've never had to change a spring.

Arteel
02-17-2011, 4:54 PM
While it's not absolutely necessary to change out the springs to function, I feel it is a HUGE improvement regarding trigger pull. At around 15.00 shipped, reduced springs are a great value.

Don't change anything until you shoot it.
I've never had to change a spring.

natchamp
02-17-2011, 5:41 PM
I also agree......fire it for a while b4 Messing with the trigger springs. I installed the JP yellow springs and it wouldn't fire at all. Let me tell you when you finally get your gun together and take it to the range the LAST thing you want to hear is "click". I had to go back home install the stock springs and then got to hear "boom". Its just my opinion but I think the issue is force required to adequately fire the rimfire cartridge.

Droppin Deuces
02-17-2011, 5:58 PM
The reduced power hammer spring DOES help it run smoother. Once I had one in my lower, the the upper was flawless. I will definitely be buying another in the future.

shadow65
02-17-2011, 6:14 PM
I use my lowers for 5.56 also. That is the reason I don't like changing things around for a .22.
Defeats the whole purpose to me.
Dave

Droppin Deuces
02-18-2011, 8:38 AM
I use my lowers for 5.56 also. That is the reason I don't like changing things around for a .22.
Defeats the whole purpose to me.
Dave

Well, I look at it this way: Even if I wasn't using a dedicated lower for my upper, it takes maybe 45 seconds to swap out a hammer spring. I left the trigger spring stock so there would be no change in feel.
I sold my upper to help fund another rifle, so the lower I was using is a little lonely. But I will definitely get another.

shadow65
02-18-2011, 11:27 AM
I may have to try a set of JP's. Question: Will they work with 5.56?
Let me know if you need another upper.;)

Arteel
02-18-2011, 1:32 PM
I use JP springs in my main AR lower which I use for both my centerfire and rimfire uppers with absolutely no problems.

thunderbolt
02-18-2011, 2:43 PM
First off thanks for all the help guys. It's great to know if I have a problem the solution is only a post away.

Ok. As you might have noticed I changed the title of the thread. I took my upper out this morning and gave it a heck of a work out. Well abused it would be more accurate. Shot 400+ rnds mixed CCI mini-mags, Federal bulk, Winchester bulk, and even a box of Remington sub-sonic I found in the back of my safe.

FTF: 1 (ammo related, wouldn't fire in my U22 Neos either)
FTE: 0
Stovepipes:0

I dumped at least 15 mags as fast as I could without a single problem. The upper is now working like it should. I didn't change out any of my springs but I did tear my lower apart and verified all my springs and parts were put together properly.

Now here is the catch, I dropped the upper this morning loading it into the Jeep and the charging handle head broke clean off. D'oh!! Add to it I think the BSA red dot I mounted on it broke cause I could not get it to zero worth crap. And I don't have a set of back-up irons for it yet so I can't verify the accuracy of the upper like I wanted to. I'm pretty sure a drop like that wouldn't have damaged the upper in a way to affect accuracy so the reddot must be toast. What say you?

Arteel
02-18-2011, 3:09 PM
Sounds like the optic is at fault, but you won't know for sure until you replace it. Glad to hear the upper functions as it should now. What shooting range do you go to?

shadow65
02-18-2011, 3:17 PM
I knew it would run. Like I said, these are made to run and run reliably. No changes needed. Even though they may look like other kits, there are differences.
Dave

thunderbolt
02-18-2011, 3:39 PM
I got out to Spenceville early this morning and thanks to the rain had the whole place to myself for almost 2 hours. It was pure heaven. Lucky for me I had the charging handle for my 5.56 upper so it was only a small hiccup in an otherwise perfect morning.

BTW anyone have any optics suggestions. :D

shadow65
02-18-2011, 5:11 PM
Check out Primary Arms for decent inexpensive optics and a company that stands behind them.

pennys dad
02-18-2011, 7:00 PM
Glad to read your 22lr upper woe's are gone.

Zeroing is a completely different animule.
What yard did you start at?
what position did you do the sight in at?
That kind of stuff

thunderbolt
02-18-2011, 7:45 PM
I set the target out at 25 maybe 30 yrds to start. The problem I was having is I would get a good group, make my adjustment and then shoot the next group and it was like I never made an adjustment. Then on a clean target with no additional adjustment made the groups would go to a completely different spot. And I'd walk it in again to bullseye only to see my POI change on the next target. All this was shot from a table with support. To test it out I shot 30 rnds at a single target taking my time and using my best techniques and the paper looked like I'd taken my shot gun to it. Small groupings spread throughout the 6 ring on in. I know I'm not that bad of a shot (at least I hope I'm not that bad a shot). So I figured either the CMMG barrel was spitting lead all over the place or the red dot had crapped out when I dropped it.

I think I'm going to steal the BUIS from my 5.56 and see if I can get a good consistant POI on the .22. At this point it's my best (and cheapest) option I think.

BTW I Love the patch. If I had weekends free I'd be out at the Appleseed trying to earn one of my own.

NorCalDustin
02-18-2011, 7:52 PM
First off thanks for all the help guys. It's great to know if I have a problem the solution is only a post away.

Ok. As you might have noticed I changed the title of the thread. I took my upper out this morning and gave it a heck of a work out. Well abused it would be more accurate. Shot 400+ rnds mixed CCI mini-mags, Federal bulk, Winchester bulk, and even a box of Remington sub-sonic I found in the back of my safe.

FTF: 1 (ammo related, wouldn't fire in my U22 Neos either)
FTE: 0
Stovepipes:0

I dumped at least 15 mags as fast as I could without a single problem. The upper is now working like it should. I didn't change out any of my springs but I did tear my lower apart and verified all my springs and parts were put together properly.

Now here is the catch, I dropped the upper this morning loading it into the Jeep and the charging handle head broke clean off. D'oh!! Add to it I think the BSA red dot I mounted on it broke cause I could not get it to zero worth crap. And I don't have a set of back-up irons for it yet so I can't verify the accuracy of the upper like I wanted to. I'm pretty sure a drop like that wouldn't have damaged the upper in a way to affect accuracy so the reddot must be toast. What say you?
Sweet! Thats fantastic news!!

I'd say its the optic... I mean, My BSA kinda sucks (replaced it with an Aimpoint).

I can't wait to see the accuracy once you get it zeroed though... Mine does fantastic with irons & the reddot. I think you'll be pleased.


Check out Primary Arms for decent inexpensive optics and a company that stands behind them.
I agree!

Of course if you want to go high-end... Obviously look at the usual suspects...

capitol
02-18-2011, 9:55 PM
thunderbolt...

just so you know there have been several complaints about the charging handle breaking off.

i understand you dropped yours, but there have been reports on other sites where they just snap in half when pulled.

pennys dad
02-19-2011, 6:41 AM
I am in agreement then that you may have a poo Red Dot.
I would try a basic crosshair 3x9 32mm scope