Determining the receiver height and other differences for your LR-308/AR-10 firearm.

[Talyn]

The receiver height on the various LR-308/AR-10 rifles vary since there is no mil-spec/standardization with this platform compared to the AR-15. Determining the receiver height is needed when finding the right handguard that will fit if switching out an existing handguard or building an LR-308/AR-10.

The common two are aptly named high and low profile. Simply measure the height of the tab that juts out above the charging handle. Low-profile receivers measure 1/8" and high-profile receivers measure 3/16".

IDENTIFYING THE DIFFERENCE BETWEEN AR-10 AND LR-308 RIFLES

 

[TEXASforLIFE]

Unfortunately there's a little more to it. Externally, yes it's a way to identify. Matrix Aerospace has ar10 (armalite) angle cut, but is dpms compatible along with barrel nut threads. He did mention the ar10 cut and could be dpms. I have also found out early on about different tang heights the hard way, but most ended up with a scope on them. The matrix I bought did state dpms compatible which was good. I do use ar10 loosely and some could get confused by me stating that? A matched set isn't the possible issue, the knowing of which design you need is. For those in any question and new to buying those platforms it's best to talk to a customer rep. Rock River 308 platform is neither of dpms or armalite, but does have the dpms receiver cut (barrel nut I don't know). The bcg is about 1" longer and uses fal mags (unsure if the newer mags have changed). Takedown and pivot pins are a little bit difference in diameter and length also (at least the 1's I have are). There a few ar15 platform manufacturers (don't remember which 1's) that are NOT miul-spec conformist. They do have their own thread pitch and receiver specs that DO NOT accept other handguards, upper and lower receivers. However, the rest is mil-spec acceptance. If they are still in business I don't know.