Building ar 308 problem

[sergeantsilent]

I'm building a AR-10 out of a CMT lower and upper, and the PMAG 25 LR/SR I have for it fits very loosely and wiggles around. What could be the issue, or is it just how it is?

[edgecrusher]

Is it AR 10 or DPMS pattern? May require a metal magazine in DPMS pattern. Is CMT an 80% build lower? 

 

As as you can see... not enough info provided.

[sergeantsilent]

Says DPMS pattern, and it's not 80%. I'm not sure what this means but this is what made me assume it'd accept pmags, "WIRE EDM MAG-WELL PROFILE IN LOWER- ACCEPTS PMAGS"

[Matt.Cross]

3 minutes ago, sergeantsilent said:

Says DPMS pattern, and it's not 80%. I'm not sure what this means but this is what made me assume it'd accept pmags, "WIRE EDM MAG-WELL PROFILE IN LOWER- ACCEPTS PMAGS"

How much wiggle, in terms of total travel distance at the bottom of the mag from side to side? Half inch, a quarter, less?

[sergeantsilent]

Probably a quarter of an inch if that. If it's how it supposed to be it's fine, I'm just used to tight fitting ar-15's.

[survivalshop]

 How tight is the Mag Catch ?

Also an Armalite AR10 Mag Catch can sometimes help .

Does the rifle function with this looseness ?

 There are no standards for the 308ARs , like MilSpec tolerances as with the little brother AR 15/ M 4 / M16 , most manufactures make their own .

Edited April 5, 2017 by survivalshop

[sergeantsilent]

I think the mag catch is fairly tight, as far as does it function I'm not sure yet I've just started building it today. From what I read I figured my lower and upper were an AR-10B and got the according mag catch, but I could try the armalite one.

[shepp]

52 minutes ago, sergeantsilent said:

Says DPMS pattern, and it's not 80%. I'm not sure what this means but this is what made me assume it'd accept pmags, "WIRE EDM MAG-WELL PROFILE IN LOWER- ACCEPTS PMAGS"

 

7 minutes ago, sergeantsilent said:

I think the mag catch is fairly tight, as far as does it function I'm not sure yet I've just started building it today. From what I read I figured my lower and upper were an AR-10B and got the according mag catch, but I could try the armalite one.

Welcome to the forum feel free to post up in the intro section and tell us about yourself 

 

which is it? That could be your issue.... 

[Rsquared]

Whoa, whoa, whoa there big fella. You're starting to contradict yourself. In terminology I mean. You said earlier that it is a DPMS pattern that accepts Pmags. Now it's supposedly a 10B pattern? Which is the Armalite pattern by the way. I think that you need to slow down and find out exactly what you have there first before progressing. Not trying to be a dick, just that you need to keep in mind that there are a couple different patterns on the large AR platform. And a couple of them are proprietary designs.

[sergeantsilent]

I figured DPMS and ar-10b were the same. On the website I got the upper/lower from it says DPMS, but with the attached file I got from armalite it looks like AR-10b.

ZZ - Tech Note 101 AR-10A AR-10B M15 COMPONENTS 120109 Rev 1.doc

[shepp]

Nope two different ball games, post a picture of your lower

[sergeantsilent]

[shepp]

https://www.cmttac.com/308-CMT-Billet-Combo-Sets?product_id=115

 

if this is what you have it looks to be dpms style even tho they say ar-10. This is why we cringe when companies say "ar10" are none armite companies and correct members when they say it with a none armilite rifle. Ar10 is the name owned by armilite, and armilite makes one of a few styles of large frame AR's, dpms style being the most popular 

 

 

[sergeantsilent]

yep that's the one. so as far as the mag catch and bolt release, do I need different ones?

[98Z5V]

9 minutes ago, sergeantsilent said:

yep that's the one. so as far as the mag catch and bolt release, do I need different ones?

Got this straight from the link that Shepp just posted:

" USES STANDARD DPMS TYPE .308 LOWER PARTS KITS / BCG/ DUSTCOVER "

There's someone on this board that just started building one of these sets, cerakoted FDE I believe.  Best to track him down or find that thread, and see what he's using, even though CMT states DPMS parts.

Edited April 6, 2017 by 98Z5V

[sergeantsilent]

Thanks guys, I asked him so hopefully I can get a response. DPMS is frustrating, everytime I google DPMS parts, the mag catch and bolt catch are always different in each "DPMS" kit.

[98Z5V]

Get it straight from a real DPMS-branded kit, and it shouldn't be an issue. 

For a complete bolt carrier and bolt parts (small parts,if needed in the future),I highly, highly recommend dwilsonmfg.com.  Dave Wilson is the man for that stuff. 

http://www.dwilsonmfg.com/store/c1/store

DPMS LR308 lower parts kits:

http://www.brownells.com/rifle-parts/receiver-parts/parts-kits/lower-parts-kits/308-ar-lower-parts-kit-w-trigger-prod81678.aspx

http://www.brownells.com/rifle-parts/receiver-parts/parts-kits/lower-parts-kits/308-ar-lower-parts-kit-less-trigger-group-prod73615.aspx

Buy quality parts from quality vendors, and it cuts down on your chances of receiving jacked up shiit that doesn't work.  My $0.02...

[sergeantsilent]

Thanks! big help

[sergeantsilent]

From what I can tell, my lower doesn't work with pmags. oh well!

[survivalshop]

Why not ?

[shepp]

1 hour ago, sergeantsilent said:

From what I can tell, my lower doesn't work with pmags. oh well!

It's dpms pattern it's 100% compatible