Any AR experts here?

[CDH]

I guess this is an acceptable topic...the forum says general and unrelated to CHL...

So I'm working on my first black rifle (actually I like the term HDR, Home Defense Rifle ) build and am just getting around to buying a receiver.

Yes I've browsed and lurked at AR15.com. That site is almost enough to scare me off of AR's.

AIM surplus has what looks like a great price on CMMG, both stripped and with internals, and Aero Precision. Good, bad, ugly? Everything I read says receivers are mostly the same except to the really really picky...

I know there is a bewildering array options for the AR platform. I'm looking for a quality, basic intro to them for my first...though I'll probably buy 2 receivers just in case.

Second question. Why are some marked .223/5.56 and some "multi"? Is there any legal reason you can't put a say 6.8SPC upper on a 223 marked receiver?

[bpet]

As I understand it, a 6.8 upper will work just fine on a .223.5/6 lower. You will need to buy 6.8 mags though.

This statement is based on what I've read and researched. I have a S&W M&P in .223/5.6 and am considering buying a 6.8 upper to use on deer sized game so I've done a little research but have not actually pulled the trigger or experienced the rush of shooting the swap out.

Good luck with your build.

[dicion]

Most Receivers are the same.. the only difference is the rollmarks mostly.

There's a few, smaller differences, but for the most part, just don't buy a junk brand and you'll be fine.

[WEC]

CMMG, to me, is a brand with a good reputation. There are some that I will swear by, but to each his own. Just like AndyC, I cannot recommend Olympic or Hesse. However, I do have an Olympic upper that has been surprisingly sturdy and accurate going on 10 years. But I bought it before I really knew anything about it, "way back when." I guess sometimes anyone can find a diamond in the rough.

[HankB]

. . . I bought a DoubleStar lower (mostly because of their good rep for customer-service) and I'm very happy with it - the lower parts kit (LPK) snapped together like Lego and now sports a Del-ton mid-length flat-top upper.

I bought a DoubleStar because it looked nicely machined and finished, and was pretty cheap. Put it together with an RRA LPK (with NM trigger) and a Vltor Emod buttstock and a CMMG upper. Have a couple of hundred rounds through it with zero stoppages.

As for the "multi" marking - personally I'd enjoy having a lower marked like that; it's kind of silly to have a .22LR, 6.5, 6.8 or .450 upper on a lower marked .223/5.56. I'm not sure if there's any real legal relevance to it, unless perhaps one were to build a pistol from it,

Whether or not you can build a pistol depends on whether or not the receiver was sold as a "receiver" or "rifle receiver" on the 4473. If the latter, you can ONLY build a rifle on it unless you SBR or AOW it. If the former, you can build a pistol on it.

[The Annoyed Man]

I had good luck with DPMS receivers, but honestly, I have no other builds to compare them to, as that's all I've used.

[CDH]

As I understand it, a 6.8 upper will work just fine on a .223.5/6 lower. You will need to buy 6.8 mags though.

That's my understanding too...I just am unsure of the legalities behind the marking. Why bother putting a caliber marking on it if there isn't a legal reason...

Then again, I'm a cynic.

[ghostrider]

>Why bother putting a caliber marking on it if there isn't a legal reason..

I'm not an AR-15 expert and I try not to play one on the internet. Until within the last few years I believe most factory AR-15's were 223/556 (and I suspect that's the most popular calibre) so I imagine for most makers just continue to have them marked that way. Its probably cheaper to 'not' make the change.

[rbraughn]

I am partial to the A,B,C,D's

Armalite, Bushmaster, Colt, Dpms and throw a rock river (RRA) in there as well

[BobCat]

Quick question for AndyC:

You said "Buy any receiver you like (except Olympic and Hesse)..." - are these two known as substandard, or what?

Not trying to be a wise-guy or argumentative - truly just asking.

I have an Olympic lower that "seems" to be fine (on a CAR-15 built from a Doublestar kit when the AWB expired in 2004) but if there are problems with them, I'd sure like to know.

This carbine does not get regular workouts like the standard-size AR I shoot in matches, so if it is flawed in some way, there is no reason to believe it would have shown up by now.

Thanks in advance.

Regards,
Andrew

[joe817]

Folks, this is a very interesting thread. Thanks to all.

But now it has my curiosity up. I know nothing about building one, so what all is involved and what are your end costs on the final product?

If I were to build one, it'd probably be a semi-auto version of an XM-177E2. What's that called, a CAR-15? I'm honestly out of my league here.

[mrvmax]

A better website for ar info:
http://www.m4carbine.net/forum.php" onclick="window.open(this.href);return false;
There is much better info there than at AR15.com

[joe817]

Excellent! Thanks!