So what do AR-10s use for mags? I've heard they use modified M-14 mags. What gets modified, the mag catch hole?

Thanks in advance.

Yes they do use modified M-14 mags.

I had an old catalog from Armalite where they had an insert discussing this. I believe the modification has to do with the bolt hold open feature.

You can use unmodified M-14 mags but they won't hold the bolt open on the last round.

I bought a bunch of M-14 mags because I wanted both the M1A and the AR-10. So I checked into this in the past.

I can no longer get the AR-10 in Cali. [>(]

I was looking into that.  The Armalite site has mag conversion kits and I think it listed the parts that came with it.  Look under the mag section.

As I understand it, you get a new follower and a new mag body in the kits.  You have to keep the old mag body around to prove that you haven't manufactured a new magazine.

Quoted: Yes they do use modified M-14 mags. I had an old catalog from Armalite where they had an insert discussing this. I believe the modification has to do with the bolt hold open feature. You can use unmodified M-14 mags but they won't hold the bolt open on the last round. I bought a bunch of M-14 mags because I wanted both the M1A and the AR-10. So I checked into this in the past. I can no longer get the AR-10 in Cali. [>(]

You got it backwards.
You can not use unmodified M14 mags in an AR-10.
You can use AR-10 mags in an M14, but it won't hold the bolt open.

How much can you get the M14 mags for these days?  I have a couple, but I haven't been in the market for awhile.

Both are AR-10 mags.
Mag on left will work in both AR-10 and M14. Mag on right will only work in AR-10.

Quoted: You got it backwards. You can not use unmodified M14 mags in an AR-10. You can use AR-10 mags in an M14, but it won't hold the bolt open.

Yep!

I have some mags like the one on the right.  They work in an M1A if you hold em in place with a tight sling.

Quoted:You got it backwards.You can not use unmodified M14 mags in an AR-10.You can use AR-10 mags in an M14, but it won't hold the bolt open.

So what course of action do I, as a novice AR-10 owner, take?

The only real option for you if you want the mags soon is to buy mag kits and build mags by taking parts off of M-14 mags.

Don Smith from Oklahoma has been advertising them in the mag forum. Magman has a site (AR-15mags.com) that also offers mag kits.

You can order mags from Armalite or send in M-14 mags to be converted, but turn-around time is slow. You can also order mag kits from them, but all three options usually end up with you on a waiting list.

Be wary of buying AR-10 mags privately. If you buy mags from Joe Blow that were made from mag kits, you need to have the stripped M-14 mags in your possession as well. This gets to be a grey area, cause who can tell what is what?

The bottom line is that if you convert a mag kit by using parts from an M-14 mag, you must have the leftover parts in your possession, or it is considered felony-building-an-evil-high-cap-magazine.

www.ar15mags.com

Proper link for Magman.

You could cut a slot in the proper place on an M-14 mag to engage the AR-10 mag catch, but I think you would have a problem with the M-14 follower. It sticks up a bit high when the mag is empty. I'm not sure what would happen when the bolt came forward on an empty mag. It might jam on the follower or ride over and scrape something up. Just a guess.

If you get new mag bodies & followers in the conversion kits, I guess the cheapest way to go is to buy those Cheap copies of the M14 mags I see for sale everywhere for about $12 & do the conversion!, Even if you later replace the cheap springs & floorplates with quality ones, This is still cheaper than using $50 M14 USGI mags for the conversion!

I have a M1A and an AR-10, so I already had the mags.

Garr is right. The cheapest way to get a legal AR-10 mag is to buy the $12 junk mags, strip their internals, use them, throw the internals away and replace with usgi springs and floorplates.

Conversion kit:     $30
junk mag:           $12
USGI mag rehab kit  $ 6

Total               $48 plus shipping for every item.

I did this with a western metal mag I found at a gunshow for $8
or

Coversion kit      $30
USGI mag           $35

Total              $65 plus shipping.

While this might not be the cheapest way to go, it is the best IMO. If the ban sunsets, all you have to do is replace the spring and floorplate in your M14 mag and you will have 2 functional mags again. Paying $12 for worthless mags is a waste of money IMO. Shop around for M14 mag deals. Every now and then you will find one for $25 or so.
Be careful buying AR-10 mags of gunbroker, ebay, etc... These could have been converted by someone, and that person hasn't included the original mag body. This is just as illegal as if you had bought the conversion kit and a spring and floorplate and put them together your self. You probably wouldn't get caught, but why chance going to prison over a few bucks?

Here are some better pics to show the dif. between the mags.

Quoted: Here are some better pics to show the dif. between the mags.

So which mags have the mag catch in the side?

If I buy a M-14 mag, I can or cannot use it in a AR-10? I don't care about the bolt hold-open feature.

Quoted: Quoted: Here are some better pics to show the dif. between the mags. So which mags have the mag catch in the side? If I buy a M-14 mag, I can or cannot use it in a AR-10? I don't care about the bolt hold-open feature.

When AR10 mags are modified Armalite does 2 things----1.Cut a small hole in the side for the mag catch and 2.Cut off half of the small lug on the side of the mag.As long as the remainder of the lug stays on the mag you can use it in a AR10 or M14/M1A.

From my own experience I can tell you the lug will usually pop off after some use as after thr conversion there is only 2 or 3 little spot welds holding it on.

In the pic,the left & center mags are AR10,the right mag is unmodified M14.You can see where the left mag still has half of the lug---it would work in a M14/M1A.The center mag has lost its lug,it would not work in a M14.

Bob,
Take a good look at the last picture. See how the follower on the M-14 mag on the right sticks up much farther than the other two mags?

When the bolt carrier on the AR-10 comes forward on that empty mag, the bolt will impact the follower.

The feed lips on an AR-10 mag are cut shorter as well. You can see that in the first two pictures. Actually, one of the three mags has shorter feed lips. Don't know if that is current design or not. I have seven mags, in about four slightly different variations.

Troy is right about the USA mags. I bought one and threw it away. Not one part of it was fit for use.

Quoted:Troy is right about the USA mags. I bought one and threw it away. Not one part of it was fit for use.

I hear you on USA mags, they're a POS.

So what do I do to get some 20rd mags? I cannot/will not pay Armalite $85 per mag. I don't want to get ripped off buying fake AR-10 mags. I'm not a machinist so I can't modify my own mags.

Am I stuck with $35 10rd mags until I hit the lottery?

How reliable are these converted mags in An AR10 after a conversion done right?
reliable as they were before conversion?

hg112
"If the ban sunsets" Hopefully well see $7 USGI M14 surplus mags again?
Possibly $20 Armalite factory 20rd mags?

I find the Red Chinese M14-mags works pretty good they feed and function flawlessly in my M1A; and the prices are still fairly reasonable relative to the USGI ones. What I would do is, buy one and do the conversion to check for fit and function in your AR10, if it doesn't work you still have your conversion kit.

I find the Red Chinese M14-mags works pretty good they feed and function flawlessly in my M1A; and the prices are still fairly reasonable relative to the USGI ones. What I would do is, buy one and do the conversion to check for fit and function in your AR10, if it doesn't work you still have your conversion kit.

Quoted: hg112 "If the ban sunsets" Hopefully well see $7 USGI M14 surplus mags again? Possibly $20 Armalite factory 20rd mags?

I think that 20rd AR-10 mags would still cost at least $30, even if the ban sunsets.
Look at the prices that Armalite currently sells the 5 and 10 round mags for.

10rd - $30
5rd  - $35