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View Full Version : Does CMMG stake carrier keys?


chunger
07-06-2007, 12:04 PM
Hello,

Doing 2 builds. . . I was wondering if CMMG stakes their carrier keys properly. . . I'm debating between buying a CMMG complete upper from Cold War Shooters or

1. buying "super duty" carrier/bolt group, complete upper, stag charging handle from Global Tactical supply 'cause they're lovingly loctited and staked and MPI tested or:

2. buying the CMT/stag complete upper set from GTS $230 which is staked properly but not lovingly loctited. $41 less than the "super duty" when all's said and done.

Then, buy the CMMG barrel assembly and assemble myself.

Cost is comparable CMMG from Cold War Shooters being a bit less but they're within $50. I'm going to have to take the barrel off anyways for FF tube on both builds, so I figured complete or not, I'm going to have to disassemble for the build.

Ordering parts on Monday. Anyone have pictures of a CMMG carrier group's stakes? I know lots of folks here love them.

Socal858
07-06-2007, 12:24 PM
my CMMG is staked properly from factory and is more accurate than my old stag.

people give CMT/stag more trouble than they deserve with all of the super duper upgrades you must get or else your rifle will fall apart in front of yoru eyes (you get the sarcastic picture).

i had no complaints about my prior stag 16" 2HT upper (it was completely factory, no fancy bolt groups / etc) ; i just wanted a 20" govt and sold it to a buddy

dont listen too hard to arfcom, they just like throwing money at absolutely nothing

proraptor
07-06-2007, 12:55 PM
Yes they are staked and yes CMMG's are super accurate

chunger
07-06-2007, 1:11 PM
Thanks for the quick replys.

Either way it goes, I'm going to be using the CMMG barrel assemblies. It seems from reading here that they are very accurate, and righteously priced. I don't think I'm looking at crazy whiz bang parts. . . am I? just the normal stuff from the normal sources.

And, the prices are really adding up to be very close as I wade through the options. Which leads me to think everyone's getting things from the same sources.

bwiese
07-06-2007, 2:09 PM
Either way it goes, I'm going to be using the CMMG barrel assemblies. It seems from reading here that they are very accurate, and righteously priced.


ColdWarShooters is a great vendor. They won't steer you wrong.

CMMG chrome-lined bbls are astoundingly accurate. They give a damn.

I don't think I'm looking at crazy whiz bang parts. . . am I? just the normal stuff from the normal sources.

If you are talking about fancy bolt carriers, special LMT bolts, 'national match' bolt carriers, etc. you don't need them. Some can cause more grief than they're worth. Just get a plain CMMG bolt assy, you'll be fine.

CMMG does stake, and you won't have problems.


And, the prices are really adding up to be very close as I wade through the options. Which leads me to think everyone's getting things from the same sources.

Prices amongst major vendors aren't *that* far apart. Some of it's just plain competition, some of it's that some raw parts all come from a few vendors/ forges and then are refined to varying quality levels by the actual co you del with. (I hear CMMG uses DPMS upper receivers. Not sure, but the finish appears to be different - and in any case, the CMMG barrels are DEFINITELY not DPMS! Also their bolts/carriers look different than DPMS)

nwnguy
07-06-2007, 2:36 PM
(I hear CMMG uses DPMS upper receivers. Not sure, but the finish appears to be different - and in any case, the CMMG barrels are DEFINITELY not DPMS! Also their bolts/carriers look different than DPMS)

I believe CMMG uses Cerro Forge uppers because of the keyhole tooling stamp that's right above the forward assist.

bwiese
07-06-2007, 3:21 PM
I believe CMMG uses Cerro Forge uppers because of the keyhole tooling stamp that's right above the forward assist.

Perhaps. That's the 'first cut'. But CF uppers may go thru someone else (like DPMS) before they become a finished upper, not sure.

PIRATE14
07-06-2007, 8:49 PM
If you really want a FF tube we can prob get those factory mounted.....

Always an option......

I do like those CMMG barrels.....used them a lot to mate w/ Mega upper rcvrs.......:chris:

chunger
08-04-2007, 5:39 PM
Well,

Finally all parts are in for my build. .. I'm very excited. . . due to an ordering error, I recieved some extra parts that I'm going to send back to Cold War Shooters (They're great BTW), but since I was curious and started this thread, might as well give a side-by-side.

Top carrier group is CMMG, bottom is CMT from Denny at Global Supply. I think he puts those manly stakes on there before they ship.

http://i7.photobucket.com/albums/y274/chungsteroonie/Library-3294.jpg

http://i7.photobucket.com/albums/y274/chungsteroonie/Library-3295.jpg

http://i7.photobucket.com/albums/y274/chungsteroonie/Library-3297.jpg

m24armorer
08-04-2007, 5:50 PM
And you did not notice the 16 carrier? Not that anyone cares as long as you do not have any other 16 parts.

chunger
08-04-2007, 5:59 PM
Noticed they were different. . . I must have got the wrong parts from GTS. I just ordered the complete Stag/CMT upper from them . . . and until the CMMG units came in, I didn't know what the difference was between the 2 types.

PIRATE14
08-04-2007, 9:28 PM
Well......a lot of AR vendors have to come up w/ somethings that don't always need fixing but if it sells.....more power to them....

We can certainly make the same mods if any one asks for them......or it's nothing that you couldn't really do yourself.....if you really thought it was necessary....

Those are some mongo stakes on that key.........;)

blackrifle
08-05-2007, 6:20 AM
I don't know how many rounds you guys shoot but a poorly staked gas key is a real life problem. The Tech. Data Package calls for staked gas keys for a reason, not because it looks cute.:rolleyes:

I can already tell you that the CMMG isn't staked quite correctly. It's close, but not quite. The Denny one is. The CMMG one looks a LOT like how I've seen Bushmaster BCG's stakes which is easy to unscrew.

Also, a problem with "MP" or "MPI" bolts is that a lot of these vendors don't actually do the High Pressure Test before the Magnetic Particle test. As the many threads on ARF have pointed out, it's pointless to have a MP tested bolt unless it's High Pressure Tested first.

As far as I know, Colt and LMT are the only companies that properly manufacture AND FULLY test each and every one of their BCG's. With LMT's costing the same as CMT's and CMMG, I don't see why you would buy anything else. Personally, I run all Colt bolts and use LMT's when I don't have a Colt one available.

Will a CMMG, CMT, RRA, DPMS, Junk-o-matic BCG blow up? Probably not the way most shooters use it but if you had to bet your life on it, wouldn't want a BCG that is fully tested (correctly)?

mow
08-05-2007, 6:41 AM
It's sort of funny that you mention LMT as a company that "FULLY" tests each and everyone of their BCGs.

Since my upper was sent back to LMT twice I would venture to guess that they don't "FULLY" test each and everyone.

http://www.calguns.net/calgunforum/showthread.php?t=32995&highlight=lmt+bolt

PIRATE14
08-05-2007, 10:11 AM
I don't know how many rounds you guys shoot but a poorly staked gas key is a real life problem. The Tech. Data Package calls for staked gas keys for a reason, not because it looks cute.:rolleyes:


10,000s of rds each year........yes it's true a poorly/improperly staked gas key will wreck parts of your rifle and put you out of the fight.....but this isn't something new.....and it's not like only now has someone miracuoulsy found a cure....

If it's my rifle, I look at the stakes, if adequate I blast away.....if not, I add some of my own, (there must be enough metal moved so that the screws look like they won't turn easily).......haven't had a key failure in over 25 years....:chris: probably have one this wkend now......

Most of my rifles are COLTs and LMTs but I have a few RRAs, STAGs, BM, Armalites.....ETC:43:

BOLTS that are PEENED, PRESSURED, and MP'd are the way to go but at least a MP inpsection would eliminate any possible metal defects and an immediate cracked bolt scenario......not pointless.......

LMT do go through a good QC program and are all thier parts are test fired but they don't normally keep them all together...ie build a complete upper test fire, box it and ship to consumer/dealer.......

My .02 is that all manufactures should test fire to a POI/point of impact, this would further elimate the canted FSBs...over/under torqued barrels......

LMTs come closest to the specs but most guys don't know what they are.....or even care....they shop by price point....brand recognition....their buddy has one...etc.

If a lot of the manufactures were suffering a high rate of bolt or key related failures they would look at their processes and make corrections......but why fix it if it ain't broke......

Satex
08-05-2007, 11:07 AM
Hello,
1. buying "super duty" carrier/bolt group, complete upper, stag charging handle from Global Tactical supply 'cause they're lovingly loctited and staked and MPI tested or:


What is special about a "super duty" carrier/bolt group?

blackrifle
08-05-2007, 4:13 PM
It's sort of funny that you mention LMT as a company that "FULLY" tests each and everyone of their BCGs.
Since my upper was sent back to LMT twice I would venture to guess that they don't "FULLY" test each and everyone.
http://www.calguns.net/calgunforum/showthread.php?t=32995&highlight=lmt+bolt
Yours is the first such problem I've heard. The initial "problem" didn't seem like a problem at all but it's hard to tell from the photos...next time, take the photo from a few feet back and zoom in and take it in daylight if possible.

The gas key not having a completely drilled hole is odd. I've never heard of such a thing. That being said, they obviously didn't test fire your particular carrier after the "repair" which is also odd but the testing I was in regards to the bolt, not the carrier.

chunger
08-05-2007, 8:37 PM
What is special about a "super duty" carrier/bolt group?

nothing is particularly special about them. . . appearantly, the parts come separately, and he assembles them and charges extra for his time.

Only difference would be:

1. gas key area cleaned, checked for flatness, and gas key/screws glued in w/ red locktite

2. gas key screws torqued to spec by hand.

3. BC upgraded extractor spring, buffer, and crane O-ring installed (cheap, readily available parts).


When I called, he seemed to indicate the normal CMT parts are fine and good to go. But, enough people feel they would like to have some extra insurance, so he has a market for another option.

I am a novice internet researcher on all of this, but for what it's worth, when I looked closely at the 2 CMMG carrier assemblies, it seemed they are indeed side-staked (not top staked) properly with material displaced around the screws. I see the CMT kits that came from GTS as over-staked just for the heck of it. CMMG seems to stand behind their product with warranty so if there is a problem with their manufacturing process, they will know about it with returns.

I had very good dealings with Cold War Shooters, Global Tactical Supply, Wes @ Tenpercent, Irvington Arms, Brownells, and a bunch of nice folks who sold me various tidbits through private sales via Calguns and arfcom. These seem like customer-sensitive companies who care about what they're doing and offer some great deals on various products! Michelle at Cold War Shooters has gone out of her way to make sure I'm getting what I need. I will continue to support these great businesses small and large.


In the end, I went with the most cost-effective option for my builds that I felt did not compromise reliability. . . while at the same time, learning a lot, having a blast, and taking responsibility for own build/purchase descisions.

ar15barrels
08-05-2007, 9:42 PM
my CMMG is staked properly from factory

Can you please post or PM me a close-up picture of the staking job?
I'm working on a collection that shows all the different brands and I want to see if their staking matches any of my "known standards" as this will tell me whose carriers they are using.

CrazyJeep
08-05-2007, 10:17 PM
Can you please post or PM me a close-up picture of the staking job?
I'm working on a collection that shows all the different brands and I want to see if their staking matches any of my "known standards" as this will tell me whose carriers they are using.

For what it's worth, I'll post some pics of the Bravo Company BCG I just recently purchased and send them to you via PM Randall. It'll probably be in the morning when I have some light.
Click me for more pictures, they range in sizes. (http://www.mediafire.com/?sharekey=052d784eb163eb5dfb949b0da091bbf7b1af436d 05eb7514)
**Edit** Here's a quick pic I took, but I will take more in sunlight. http://www1.mediafire.com/imgbnc.php/3962f21660dda967be6fee9d4441d2c94g.jpg (http://www.mediafire.com/imageview.php?quickkey=3cmtsdyj2dj&thumb=4)

chunger
08-06-2007, 2:37 AM
Here's some close-ups of CMMG. . . sorry about the cheap camera.

http://i7.photobucket.com/albums/y274/chungsteroonie/Library-3305.jpg

http://i7.photobucket.com/albums/y274/chungsteroonie/Library-3303.jpg

http://i7.photobucket.com/albums/y274/chungsteroonie/Library-3299.jpg

blackrifle
08-06-2007, 2:45 AM
The CMMG look ok but the one on the right doesn't look like it's staked enough. I had some Bushmaster carriers staked like this photo below and the screws came loose...
http://www.vaq34.com/stake3.jpg

BTW, I just remembered that I saw a few CMMG uppers that came into a dealer I know (several months back) and they carriers looked like Stag/CMT carriers because the staking was the same (they were just stamped with a flat head screwdriver) I don't know of any other manufacturer that stakes their keys incorrectly like that.

Here's a great quote by Pat Rogers:
I start all of my classes now by having the students show me their BCG. The number of unstaked/ poorly staked gas keys is amazing, and running at appx 30% in the open enrollment classes.
We generally don't see this issue in the mil classes because Colt and FN are held to a standard, while the other tier makers apparently do what they wish (or don't do, or do poorly). I don't believe that i have ever seen an unstaked/ fifi staked gas key on any mil gun (again, Colt and FN).
...
For those low end makers that can't be bothered to stake the gas keys, the Ned Christiensen MOACKS (look for the SWAT magazine article in the Oct issue on this jewel) works like a charm, and mine gets a lot of use.
...
Not all makers build up to a standard, and i am shocked at how many aftermarket guns show up at class with major problems.
As my Dad said- "Buy cheap, buy twice".
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