Home Forums Hunting & Shooting AR and Tactical Rifles Magazines for large frame ARs

Maybe we can compile enough info here in a single thread to make it a reference on mags for AR10s & LR308s. I'd like to have found such a thread a few weeks back...

So I have finished up a project gun started by my deceased neighbor. He bought good stuff, but the buffer and spring were mismatched to the receiver extension and there were functional issues as a result. The rifle seems to be a great performer now that the buffer issues have been resolved. When I acquired it I got two Magpul polymer 20-round mags and a metallic ASC 10-rounder. If it matters, the rifle is chambered in .260 Remington. As an AR15 shooter I was never fond of Magpul or any other polymer magazine. In fact, I became more a fan of ASC magazines as an AR15 shooter and specifically because I built two AR15s in 6mm AR, and ASC 6.5 Grendel mags allow about the longest cartridge OAL of all of them and they function perfectly. Figuring I'd not use the Magpuls in the .260 I bought two more ASCs for it, 20-rounders. Once I had the rifle figured out and got it functioning correctly I discovered that these ASC mags are pretty much worthy of the dumpster while the Magpuls function flawlessly. Three more Magpuls found their way into my mailbox after this discovery.

So, the questions are:
- what works?
- what does not work?
- what works in some situations but not in others?
- most importantly (if the answers are known) WHY?
- are there any good fixes guys should know?

I'd still like to know what the good metallic mags are and what the junk metallic mags are because I just don't have a lot of confidence in polymer magazines. I did see Magpul mags recommended in my searches, and also Armalite mags, but I haven't found much more in the way of in-depth discussion of these questions anywhere on the web...so here I am asking.

Stick with armalite mags for Armalite rifles and gen 3 mags for gen 3 guns...mb

I’ve had issues in 2 LR308 rifles with ASC and Stoner metal mags. Zero issues with MagPul mags.

Thanks for your response...

What are "gen 3 mags" and "gen 3 guns?" The implication is that there must be also a gen 1 and a gen 2. What are they?

During my explorations, I think I found that Armalite mags are no longer available (I could be mistaken due to information overload), but I was under the possibly mistaken impression that they were useable in LR-308 framed guns. Are the Armalite mags useful only in the Armailte pattern AR10 platform?

Mag well on a Aero m5 lower ( gen3) what p mag calls them has different dimensions than a Armalite mag well. They do not interchange. The guide rail on the back of an Armalite metal mag is wider than the groove for it in a gen3 Aero m5 mag well. Armalite mags have a groove on each side just behind the mag retention slot these grooves like on metal AR-15 mags are for the striper clip shoe to refill the mag with 5 rd stripper clips. Armalite still makes the AR -10 so they still make mags. I am sure you ask them, they would tell you that they aren't responsible for their mags fitting in all the ar-10 clones...mb

So, you're saying that there are two types, essentially. Those intended for the Armalite AR10, and those that work for the DPMS pattern LR-308. Is that correct?

And what about "gen 3?" What does that mean? That implies the existence of Gen 1 and Gen 2. What about those? What was changed and how did it affect compatibilities?

(I understand some of this, but not all. I am asking for clarity because the intent is to get the info all in one place in condensed form to benefit the next guy.)

I'd also like to know more about others' experience with various metallic magazines---what works, what doesn't. So far, my own extremely limited experience mirrors JPro's except I haven't tried Stoner's mags, and I'm not likely to do so (thanks, JPro).

real simple here, you buy Armalite mags for Armalite guns or clones that say they are for Armalites. P mag one of the largest mag manufacture makes their polymer mags that fit gen1, gen ll lr308 dpms pattern guns their latest mags in a bag has some design change and called gen lll don't have gen l or gen ll gun but have been told they interchange with gen lll mags for fit and function.
Got it? I only have what I have and can't tell you what I don't know , ar-15 components are more interchangeable. Don't ask advice from minimum wage clerks. They don't know...mb

RR THE RUGER SFAR is yet another different gun...mb

For those in confusion-

ArmaLite AR-10 "B" uses a modified M14/M1A magazine.
gas tubes are 1/2-5/8"longer than AR 15 length gas tubes.

ArmaLite AR-10 "A" uses LR308/PMags.

ArmaLite receivers are 45degree angled at the aft bottom corner & not a radius aka AR-15 or LR308 receivers.

ArmaLite uses ,750" carbine & rifle & .875" rifle "T"diameter gas journals...only.


OP,
For your LR308 mag pattern options-
Brownells offered an aluminum 20rd mag copy of the vintage AR-15 mag.
The stiffener ribs in the above mag will bind feeding at the case head.
The above also work better w/ MagPul 20rd mag springs.
ASC mags copy the AR-15 mag body profile...also.

Lancer L7 mags are the best option(steel feed lips) to any plastic lip MagPul mag in the LR308 lowers & provide the longest COAL.

Lancer L5 mags are AR-15 pattern mags.

The ones I find work for the LR308 pattern rifles are the Magpul and the ones where the follower has a rounded half case molded into it (Brownells, D&H, etc). Ones with a squared off follower seem to feed poorly in my experience.

I purchased four D&H mags a couple of weeks ago and took them and a newly assembled AR in .260 Remington to the range early last week. Both the rifle and the mags worked great.

So, based on my own experience the good magazines are:

- D&H
- Magpul