.308 Lower Compatability

[pjmeado]

So in the .308 world of lowers, I keep hearing how one brand does not fit well with another. Is there a .308 lower that is universaly compatable or should I stick to one manufacturer?

[rc50cal]

i was looking in to putting together a AR 308 rifle a few months ago. Here is what I remember: there is no universally compatible setup. You need to pick from one of three choices (I believe):

1. AR-10 type - Armalite and Noveske
2. DPMS type - DPMS, POF, others
3. RRA type - RRA only I think

I am no expert yet, so someone might be a long to correct some or all of my post. Also, I remember reading dozens of posts about this topic here on Calguns. If you search for it, you will find it.

[pjmeado]

Thanks rc50cal. I'll look into that. I have to say that if those are the choices I'll be going with choice #1

[rc50cal]

I don't think that would be a mistake, but be forewarned. Parts are few and far between for Armalite and Noveske. Noveske can't even get parts from Armalite right now in order to build their rifles.

[pjmeado]

Yeah I've noticed that. I'm a few days...and a BCG away from finishing my 1st build so I will have something to play with until I can gather all the parts I need again.

[ar15barrels]

[C.G.]

i was looking in to putting together a AR 308 rifle a few months ago. Here is what I remember: there is no universally compatible setup. You need to pick from one of three choices (I believe):

1. AR-10 type - Armalite and Noveske, AERO, Aircraft Armament, in future CMMG
2. DPMS type - DPMS (not legal in CA), POF, Fulton, CMMG, Remington (only sold as complete rifle as far as I know.
3. RRA type - RRA only I think

I am no expert yet, so someone might be a long to correct some or all of my post. Also, I remember reading dozens of posts about this topic here on Calguns. If you search for it, you will find it.

Some corrections/additions.

[BlackViper]

I already have an Aero AR-10 stripped lower, but was looking at a CMMG this afternoon over at J&R in Livermore.

Here's my question, are the 308 uppers all the same? Seems so from Randall's photo. Or, does having one particular type of lower restrict you to a particular mfr of upper?

I want to build my 308 into a 1000yd rifle, something like the KA's M110. I might actually go with a different lower, I'm not that crazy with the Aero compared to some of the newer mfrs coming out with 308 lowers.

[C.G.]

I already have an Aero AR-10 stripped lower, but was looking at a CMMG this afternoon over at J&R in Livermore.

Here's my question, are the 308 uppers all the same? Seems so from Randall's photo. Or, does having one particular type of lower restrict you to a particular mfr of upper?

I want to build my 308 into a 1000yd rifle, something like the KA's M110. I might actually go with a different lower, I'm not that crazy with the Aero compared to some of the newer mfrs coming out with 308 lowers.

If you look at Randall's photo closely, you will see that there are two different style of uppers (maybe three, not sure about RRA stuff) AR-10 pattern and DPMS .308 pattern. Your Aero will fit the AR-10 pattern uppers.

[ar15barrels]

Armalite upper on a DPMS lower.



Now do you see the difference?

[C.G.]

Armalite upper on a DPMS lower.



Now do you see the difference?

Randall, by any chance would you know if the SR-25 upper fits an Armalite lower? They seem close in photos.
The reason I ask is that I am thinking about doing something with my HAR-25 lower, which is milled for DPMS mags and rather than modding an Armalite upper I thought about getting an A-2 SR-25 upper from Armalite's close out. Unfortunately, Armalite is very tight about information (they just said it won't fit, but no specifics).

[ar15barrels]

Randall, by any chance would you know if the SR-25 upper fits an Armalite lower?

I don't know.
Pin centers may be different.
DPMS and SR25 mags and magwells interchange.
The fit problem MAY be related to the SR25 uppers not having the stop shelf for an AR-10 mag.
In that case, they would be a good match for an HAR25 lower with a DPMS magwell.

Here are the stop shelves that an AR-10 upper will have:



Those shelves get milled out to work with a DPMS mag.

[BlackViper]

Randall I will call you when I finally get serious about putting my AR-10 together.

[rc50cal]

Some corrections/additions.

That's right. DPMS is listed, which is a shame because their rifles are reasonable priced. To further illustrate the crazy laws of our state, the Remington R-25 is not listed and therefore compliant with a simple bb even though it is made by DPMS.

[ar15barrels]

That's right. DPMS is listed, which is a shame because their rifles are reasonable priced. To further illustrate the crazy laws of our state, the Remington R-25 is not listed and therefore compliant with a simple bb even though it is made by DPMS.

Fulton's 308 is also a re-branded DPMS.
It's not listed either.