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sigsr
12-01-2009, 6:50 PM
Noobie question. Are the CMMG lowers mil spec? Will they take the commercial or mil spec buffer tubes?

Okami
12-01-2009, 6:50 PM
Yep, they'll take both.

aplinker
12-01-2009, 7:05 PM
Noobie question. Are the CMMG lowers mil spec? Will they take the commercial or mil spec buffer tubes?

mil-spec is essentially meaningless - or rather, it has a ton of different meanings when used: marketing hype (lies), styles (like the carbine tubes), real deal TDP, when used to refer to a stock/standard item (like mil-spec trigger vs. match), etc. etc.

In the case of your question, what we define as a "mil-spec" lower would be one that takes a standard lower parts kit. That does NOT mean the lower is actually mil-spec - it could be cut slightly different (aesthetics, general differences), it could have a different material (plastic, 6061 aluminum), it could be billet, etc...

ALL "mil-spec" lowers will take "mil-spec" AND commercial carbine receiver extensions. What defines mil-spec and commercial for receiver extensions are their dimensions and how it is made (forging vs. other).

Perhaps this would be helpful:
www.magpul.com/pdfs/technotes/ctr/buffertubeid.pd

GearHead
12-01-2009, 7:07 PM
mil-spec is essentially meaningless - or rather, it has a ton of different meanings when used: marketing hype (lies), styles (like the carbine tubes), real deal TDP, when used to refer to a stock/standard item (like mil-spec trigger vs. match), etc. etc.

In the case of your question, what we define as a "mil-spec" lower would be one that takes a standard lower parts kit. That does NOT mean the lower is actually mil-spec - it could be cut slightly different (aesthetics, general differences), it could have a different material (plastic, 6061 aluminum), it could be billet, etc...

ALL "mil-spec" lowers will take "mil-spec" AND commercial carbine receiver extensions. What defines mil-spec and commercial for receiver extensions are their dimensions and how it is made (forging vs. other).

Perhaps this would be helpful:
www.magpul.com/pdfs/technotes/ctr/buffertubeid.pd



You cut off the "f" on ".pdf"

jawcn
12-01-2009, 7:09 PM
Noobie question. Are the CMMG lowers mil spec? Will they take the commercial or mil spec buffer tubes?

Not a big fan of CMMG... but it seems like we do not have much choices in Cal...

tomd1584
12-01-2009, 7:31 PM
Not a big fan of CMMG... but it seems like we do not have much choices in Cal...

Not a lot of choices??? Joking?

There are PLENTY of choices my friend.

CHS
12-01-2009, 7:54 PM
but it seems like we do not have much choices in Cal...

Clearly you haven't been paying much attention...

aplinker
12-01-2009, 8:04 PM
Not a big fan of CMMG... but it seems like we do not have much choices in Cal...

I would say for every "banned" receiver there at least a dozen options to replace them.

In fact, I can't think of a single listed rifle there exists no clones for.

a1fabweld
12-01-2009, 8:27 PM
Something to think about with a CMMG lower is that they are Teflon coated after anodizing which makes the finish somewhat shiny. It's a good thing & bad. Most uppers are only anodized which looks "duller" when mated up to a CMMG lower. Some folks care, some don't. The Teflon adds an extra layer of durability to the finish OTOH. CMMG has proven to me to be good stuff.

97F1504RAD
12-02-2009, 8:29 PM
So a commercial and/or mil spec buffer and tube assembly will fit on any lower receiver.

But you cannot interchange a mil-spec collapsible stock with a commercial tube and vice versa correct.

Can someone tell me the difference between these two stocks?

Magpul CRT vs Magpul MOE

CHS
12-02-2009, 9:19 PM
Magpul MOE: Basic collapsible stock. Replacement for the standard M4 stock.

Magpul CTR: Same as above, but has hardened steel insert for QD sling swivel attachment, and friction lock to remove all slop/wobble from stock.

Both are available in commercial or mil-spec diameters.

mydogsmonkey
12-02-2009, 10:39 PM
also, i believe to get a true mil-spec lower, you would need that extra hole for the auto sear(big no-no)

Ernest

missiontrails
12-03-2009, 6:52 AM
Something to think about with a CMMG lower is that they are Teflon coated after anodizing which makes the finish somewhat shiny. It's a good thing & bad. Most uppers are only anodized which looks "duller" when mated up to a CMMG lower. Some folks care, some don't. The Teflon adds an extra layer of durability to the finish OTOH. CMMG has proven to me to be good stuff.

Mine are not gritty gray/black, buy they are definately NOT shiny either. That Teflon over anodizing is a tough finish, MEGA does the same thing on the new billet lower/upper.

97F1504RAD
12-03-2009, 7:28 AM
Magpul MOE: Basic collapsible stock. Replacement for the standard M4 stock.

Magpul CTR: Same as above, but has hardened steel insert for QD sling swivel attachment, and friction lock to remove all slop/wobble from stock.

Both are available in commercial or mil-spec diameters.

Thank You

DB2
12-03-2009, 8:54 AM
Yes as others have stated, they are milspec. CMMG does not do their own machining of their lowers. The company that machines them does excellent work.

Motor Man
12-03-2009, 3:05 PM
If the commercial tube is wider than the milspec, are the threads the same on both? A commercial tube will tread into a milspec lower even though its slightly bigger?

shark92651
12-03-2009, 3:36 PM
If the commercial tube is wider than the milspec, are the threads the same on both? A commercial tube will tread into a milspec lower even though its slightly bigger?

The threads are exactly the same, the diameter of the tube behind the threads is different.

Motor Man
12-03-2009, 4:38 PM
Good to know. I had a gunsmith tell me that you can screw up the threads in the MilSpec lower by trying to put on a commercial tube. Something about it won't tread on easily or all the way. Guess it isn't something to worry about unless you can't get it on, in that case, don't force it.

shark92651
12-03-2009, 4:41 PM
Good to know. I had a gunsmith tell me that you can screw up the threads in the MilSpec lower by trying to put on a commercial tube. Something about it won't tread on easily or all the way. Guess it isn't something to worry about unless you can't get it on, in that case, don't force it.

I'd recommend a new gunsmith, at least one that has put together an AR-15 before because that one seems very confused.

CHS
12-03-2009, 4:54 PM
Good to know. I had a gunsmith tell me that you can screw up the threads in the MilSpec lower by trying to put on a commercial tube.

Gunsmiths are the second leading source of CRAP information, right behind your average gun store employee.

Motor Man
12-03-2009, 6:20 PM
This guy I got the info from said he has built many AR's and works on them everyday, having about $3000.00 in special tools just for the AR's. All this and yet something this simple he gets wrong. Maybe I just misunderstood what he was trying to tell me.

aplinker
12-03-2009, 7:01 PM
Gunsmiths are the second leading source of CRAP information, right behind your average gun store employee.

Says the average gun store employee. :D

Is this like one of those, "90% of all statistics are made up," statements that nullify themselves?

CHS
12-03-2009, 8:04 PM
Says the average gun store employee. :D


I am not an AVERAGE gun store employee :)

shark92651
12-03-2009, 9:54 PM
I am not an AVERAGE gun store employee :)

Nor do you work for an AVERAGE gun store ;)