Contemplating buying an ar10. I am all about compatability lately and have heard m14 mags can work in certain ar10 styles. Is there a mag that works in both with no modification or are mlds needed to mske it work in both. I am not opposed to modding mags as long are they are still compatabile in both rifles. I will be buying an m14 in the future

As far as I know, there isn't an Armalite that will take both DPMS-pattern mags like the Magpul PMAGs and Armalite's proprietary modified M14/M1A mags. The AR10A takes the DPMS-pattern mags while the AR10B takes the modified M14/M1A mags.

decisions...decisions

Sounds like you may be in guinea pig territory here.

 

You can elect to go with M14 mags and modify them for AR10B duty.  A quick search resulted in issues with the bolt not holding open or barely holding open post modification.  Some posts say once you modify the M14 mag for AR10 duty, it no longer works on the M14.  I think it really depends on what modification is done though.

 

Personally, I'm not a big fan of trying to modify things to work on multiple platforms if there are compromises that it does not work perfectly in either system.  I understand the desire to not stock that many different types of magazines or the cost savings of not buying too many magazines.

 

You can always get the Checkmate 15 rounders for the M14 and the MidwestPX PMAGs for your AR10A or DPMS308.

I owned a couple of the ArmaLite AR10s(2 AR10Ts, and 1 AR10A4) that were designed to work with modified M14 magazines. The selling point at the time was grandfathered M14 mags for easy conversion, when new construction hi caps were verboten save for Mil/LE. That's no longer the case, and even ArmaLite finally caved and built a receiver to utilize the more standardized original pattern ArmaLite magazines now in use by most manufacturers. It's one or the other, not both.

 

I can tell you that the magazines themselves were more complex, with additional springs and parts not normally found on followers, to try and engage the bolt stop. I don't believe they worked in the M14 pattern with the different follower, either. Magazine reliability was a real issue at the time, too. Some worked, some worked with tinkering, and some simply didn't...ever. Mags that fed didn't always lock the bolt back, and vise versa. In some cases, removing the added springs and pins for the bolt hold catch resulted in a magazine that would at least feed, but not lock open on empty; the lesser of two evils. If you read AR15.com at the time, the main forum for AR10 users back then, it was a constant source of frustration for those of us who owned the rifles, and various attempts to make the mags feed better were constantly being explored...

 

I would strongly recommend you look at a model that takes a traditional AR10 magazine. With the availability, reliability and low cost of LR-20s from Magpul, the idea of buying this rifle for another you may get in the future, in an attempt to have magazine compatibility, just to have the headaches over the mags, is less then ideal.

 

I own a POF P308 now, and fed with the aforementioned LR20s, it is a much nicer platform with many less headaches then any of the ArmaLites I wrestled with in the past... 

 

As in all things YMMV, and mine is a sampling of three with about a dozen magazines, and about five years of working with the platform.

Well since i just ordered a discounted fal from atlantic firearms i plan on getting the RRA LAR-8 so i cwn share mags between the two

I really like the Rock River .308' but won't buy one because of the mag choice. If the rifle won't shoot PMAGs, I don't want it.

Well since i just ordered a discounted fal from atlantic firearms i plan on getting the RRA LAR-8 so i cwn share mags between the two

AR-10 PMAGs are $18, it sounds you are paying $500-$800 more than DPMS to get a gun so you can share mags between them?

 

I don't know much about AR-10s, maybe there's more to the price point. They do seem to vary a lot with configuration, even on the DPMS end.

The lar 8 can be had for about 1250. Around the same as other ar10's. I just like the fact that they will share mags.

I custom built both of my LR308 (DPMS pattern) and they were great for not much more than by an LAR8 from RRA.  PM if you want specs and costs.  The LR308 uses PMags.  I sold one of the two to a forum member.