While I have had an AR-15 for at least 10 years now, I just haven't done much to the platform other than some minor mods (quad-rail hand guard, bipod, WML). I was just thinking it would be nice to slap on a .308 upper when I wanted to switch calibers, but is that even possible? I know AR-10s LOOK like an AR-15, but are the uppers interchangeable like that? If so, where do you recommend purchasing an upper from to fit a Ruger AR556 rifle?

Thanks!

No, although the POF Revolution and Ruger SFAR are close in size.

Not to mention, how would you feed that AR-10 upper? .308 mags aren’t going to fit in that AR-15 lower.

Not interchangeable. Ruger SFAR is what you seek.

quote:

Originally posted by Dwill104:
Not to mention, how would you feed that AR-10 upper? .308 mags aren’t going to fit in that AR-15 lower.

That was the first thought that came to my mind... the mags would be too large to fit the lower.

quote:

Originally posted by IndianaBoy:
Not interchangeable. Ruger SFAR is what you seek.

That's what I expected, but wanted to hear from what those more experienced in the platform could tell me. Thanks!!!

If you would like you could look into some of the alternate calibers that would get you close on either power of a 308 or range of a 308 that still fit in an AR magazine.

Alternatively, by the time you consider buying an upper and investing in what may be harder to source and, therefore more expensive caliber, it may just be cheaper to get an AR10.

Would definitely prefer to stick with the .308Win round as I've owned and shot it before, and consider it a "standard" round (common availability) with excellent ballistics. I've owned plenty of others also, but still default to .308 when push comes to shove...

Actually, an AR-10 lower that accommodates an AR-15 upper exists. I have one and they are extremely hard to find. It is the Colt LE901-16S. It consists of an ambidextrous .308 lower with an adapter. The mag well adapter allows you to use either a .308 or a 5.56 upper. Here is a link for one article.

https://sadefensejournal.com/t...le901-modular-rifle/

It works very well. It came from Colt with a .308 monolithic rail upper. But it only takes a second to install the adapter, switch out the buffer and put a 5.56 upper on it. I’ve had mine for several years. It’s one of those things that Colt made and then stopped. I really don’t understand why they don’t still manufacture a .308 rifle. The ambidextrous lower for this set up is well made and functions beautifully.

Will update later with some pictures.

This message has been edited. Last edited by: Sauer Kraut,

I'll bolster Sauer Kraut's post; the 901 is a fine rifle.

I bought one in maybe 2013ish, and it'll put ten rounds into an inch, at 100M, with Nosler 168gr Custom Competition factory-loaded ammo. That's with a chrome-lined barrel, shooting semi-auto. It is my "DMR". I was fortunate enough to stumble into a barely-used one at the LGS last year, at a good bit less than what I paid for a new one a decade ago; I bought it. Fine as the 901 is, it has a good many proprietary parts, and having a backup seems like a good idea.

I have configured it with a 5.56 upper as well, and it works perfectly. It is versatile, and arguably does the caliber conversion thing as good or better than some of the other AR18 systems. If you want .308 and 5.56 in the same gun, in other systems, you're going to be shooting your 5.56 out of an oversized rifle. With the 901, you get to trim the fat of the entire upper receiver.

I say that Colt would have done well to make the same lower in a small frame, and put their 6940 and 6940P uppers on it. Those guns would have been very nice.

The way I understand it, Colt made the 901 and 6940 uppers under license from LMT. LMT had the monolithic patent, and Colt was the only outfit that properly paid to use it.

The only bummer about the 901 is silencer application. Mine couldn't get through three rounds without a problem. Thankfully, there's some odd 901 parts floating around for cheap. I got another carrier and added a vent port; it's been flawless ever since.

This message has been edited. Last edited by: KSGM,