Q: AR-10 pattern v. AR-15 pattern - what interchanges?

[The Heretic]

I know there is no official mil spec for the AR-10 pattern rifles.

Q1: Is there a spec that most manufacturers follow for the AR-10?

Q2: What AR-15 parts will fit on most AR-10 rifles? I am especially interested in trigger groups and lower receiver parts.

Q3: What AR-15 uppers will fit on what AR-10 lowers?

Trying to get a feel on these kinds of issues for a possible build. I would like an AR build that would allow me to have the widest possible choices in uppers on an AR-10 lower so I could use a 7.62x51 upper too. I would also like to be using a binary trigger, most of which seem to be made for AR-15 lowers.

TIA

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[Stomper]

I know there is no official mil spec for the AR-10 pattern rifles.

Q1: Is there a spec that most manufacturers follow for the AR-10?

Q2: What AR-15 parts will fit on most AR-10 rifles? I am especially interested in trigger groups and lower receiver parts.

Q3: What AR-15 uppers will fit on what AR-10 lowers?

Trying to get a feel on these kinds of issues for a possible build. I would like an AR build that would allow me to have the widest possible choices in uppers on an AR-10 lower so I could use a 7.62x51 upper too. I would also like to be using a binary trigger, most of which seem to be made for AR-15 lowers.

TIA

A1: no. Armalite has their pattern, then everyone else has there own nuances. Magazine compatibility is the major concern.


A2: it seems AR15 LPK's will work in AR10 lowers.

A3: dedicated AR10 powers are NOT compatible with dedicated AR15 uppers, however Colt (and Olympic Arms) does make a "convertible" AR pattern rifle

Colt Modular Carbine CM901

New From Olympic Arms: Convertible AR-10/AR-15 - The Truth About Guns

Colt 901 Modular .308 & .223 Carbine - New Gun Review - LE901-16S - GunsAmerica Digest


Just found a modularly convertible by Windham Weaponry, but .308 isn't one of the calibers...


Windham Weaponry RMCS-4 Multi-Caliber Rifle Kit

 

[The Heretic]

Yup - read about the Colt. I wasn't sure whether it would only take Colt uppers or any mil-spec upper. I read now they claim to take any mil-spec upper. Googling to see if it is available as a pistol (I want my cake and to eat it too).

I seem to recall something about Windham. Did not hear about Olympic

 

[3MTA3]

Many manufacturers use the DPMS large frame pattern, but it's still a crap shoot as there are also two different heights. My AR 308 is based on the DPMS GII short frame pattern and it has more compatibility with an AR-15 including hand guards and rails, buffer tubes/extensions. The claim is 85% compatibility with AR-15 parts. While shorter and lighter than a large frame it isn't compatible with AR-15 uppers.

 

[The Heretic]

Well, it just might be better if I get both AR15 and AR10 patterns, going for the most compatible on the latter.

Mostly I was interested in parts compatibility, especially the trigger group (which I kind of figured would be compatible) because of the advent of binary triggers, but upper compatibility would have been nice.

I also wanted a pistol lower so I could have the option of a 7.62x39 "pistol" that was legally concealable in a vehicle.

 

[3MTA3]

Well, it just might be better if I get both AR15 and AR10 patterns, going for the most compatible on the latter.

Mostly I was interested in parts compatibility, especially the trigger group (which I kind of figured would be compatible) because of the advent of binary triggers, but upper compatibility would have been nice.

I also wanted a pistol lower so I could have the option of a 7.62x39 "pistol" that was legally concealable in a vehicle.

If it were me and I was building I'd go with Aero Precision. If I wasn't building but just wanted to be able to upgrade the trigger and use AR-15 LPK's to replace parts as they wear out I'd look hard at the S&W M&P 10. They are on the light side due to a well thought out barrel taper, accurate, and reliable. Price is really good as well. Some pistol grips won't fit a large frame AR-10, but there are some specifically designed for it like the MagPul MIAD AR 10 version. If I wanted the most AR-15 parts compatibility, then something that uses the GII pattern like Adams, DPMS GII, and Remington come to mind.

 

[The Heretic]

One requirement is a removable trigger guard on the lower - the Digitrigger requires this for installation.

 

[3MTA3]

One requirement is a removable trigger guard on the lower - the Digitrigger requires this for installation.

That pretty much rules out everything except the Armalite AR-10. I don't know about it's compatibility except that it is different from all the other AR-10/AR308 patterns.