CMMG barrel doesn't fit

[jebarton3]

Hey guys, so I'm actually building my first 308 SBR and I seem to have run into a problem. I just got a CMMG 12.5 308 barrel in today and it doesn't seem to fit into my CMT upper. The CMT upper is a dpms pattern high profile and I was under the impression that the CMMG barrel would fit? Am I'm missing something here? Is this barrel an AR patterned barrel and not a dpms pattern? Or should the barrel fit? Thanks.

[jtallen83]

Should is the operative word here.

Someone will know the right way, you need to freeze one part and heat the other then squeeze them together...just can't remember which is which right now...........

[shepp]

16 minutes ago, jtallen83 said:

Should is the operative word here.

Someone will know the right way, you need to freeze one part and heat the other then squeeze them together...just can't remember which is which right now...........

I would assume freeze the barrel (compress) heat the upper (expand). But I don't know exactly either

[jebarton3]

Hopefully someone that knows will chime in. Thanks guys! Really looking to get this together and hit the range!

[ARTrooper]

haha, an example of cmmg giving problems like someone brought up a few weeks back. sad, such good looking uppers and lowers too.

[jtallen83]

57 minutes ago, shepp said:

I would assume freeze the barrel (compress) heat the upper (expand). But I don't know exactly either

Everything I'm reading says this, freeze the barrel and heat the receiver.

[jebarton3]

I can barely get it started. I'll try it out in the morning and report back. thanks guys.

[blue109]

6 minutes ago, jtallen83 said:

Everything I'm reading says this, freeze the barrel and heat the receiver.

I've never needed to do that. If you need to do that than something is out of spec and I wouldn't go any further until I figured out what it was.

[Robocop1051]

**cough**

[sketch]

If i were to bet rob was a bettin man and he lost a bet that earned him a cmmg tatt he would double down on parts!

[sketch]

Glock! 

[planeflyer21]

4 hours ago, Robocop1051 said:

**cough** Never had that problem with any of my Glocks.  Just sayin'!

FIFY!

You knew it was coming eventually. 

[survivalshop]

6 hours ago, blue109 said:

I've never needed to do that. If you need to do that than something is out of spec and I wouldn't go any further until I figured out what it was.

This ^^^^ , Measure the inside dia. of Upper receiver & the outside of the bbl. to see how close they are to each other . Decent digital or dial caliper will work .

 I also have never had to do the freeze / heat thing to assemble a barrel on any AR . You can run the risk of cracking the Upper receiver , if its too tight .

 What Finnish is on the Barrel's Extension  & some photo's would be nice .

[jebarton3]

Ok, I must have been tired when messing with it last night. 

[Matt.Cross]

Hooray? 

 

Really, should we celebrate the successful addition of a CMMG part to a friend's rifle? Yes we should, because we can laugh our asses off later when it gives them problems....

[jebarton3]

It's temporary as the 12.5 barrels are sold out everywhere and have been for months.

[jebarton3]

53 minutes ago, Matt.Cross said:

Hooray? 

 

Really, should we celebrate the successful addition of a CMMG part to a friend's rifle? Yes we should, because we can laugh our asses off later when it gives them problems....

This barrel was the only one I could find and even these are sold out on other sites.

[shepp]

4 hours ago, jebarton3 said:

This barrel was the only one I could find and even these are sold out on other sites.

They're  just teasing, cmmg is kinda a whipping boy around here due to incompetent standards. 

 

Btw welcome to the forum, feel free to post up in the intro section! Build looks like it's coming along nicely 

[Matt.Cross]

I was just teasing, as Shell said. Ya gotta do what you gotta do sometimes!

[jebarton3]

Thanks guys this is the finished product. Just waiting for this weather to clear up to go run it. Thanks for all the input!

[98Z5V]

Damn sweet SBR!