Nevermind...I'm an idiot.....

The direct gas impingement AR system has more sensitive cleaning requirements than gas piston. Keeps carbon build up and powder residue from reaching - and fouling the Upper Receiver and Bolt Carrier. Not that it matters but direct gas weapons heat up faster under sustained full auto than gas piston. If you'd rather be shooting than cleaning... gas piston all the way.

The only 2 ARs I would even consider are:

HK 416 (BATFE rules limit availability to uppers only)
Robinson XCR

The Bushmaster gas piston is still new and I haven't heard much about it yet.

Have you considered 7.62mm... aka .308Win? Not sure what your end use will be but, 5.56 flight path is more easily interfered with by glass and brush. 7.62 will go through cars and cinder block walls. This might be an issue if you hunt through heavy brush.

The downside is a typical 20rd mag in 7.62 vs. 30rd 5.56 STANAG mag.

It's going to be mainly for target shooting and home defense. Does the HK upper fit with other AR models?

Originally Posted by RDial

It's going to be mainly for target shooting and home defense. Does the HK upper fit with other AR models?

I've only seen complete HK units. You should consult with an armorer to have him do the integration work. BATFE restrictions relate to importation.

Robinson XCR is home grown US and available as complete units. I have not heard of any problems thus far and has been around for 2 years now. It was developed for SOCOM's SCAR evaluations but was disqualified on a technicality due to late delivery of blank firing adapters. It is also alot cheaper than trying to integrate a HK416 upper.

I know piston uppers are all the rage right now, but all the plain-vanilla Colt impingement guns in our battalion have worked fine out here. No complaints from the guys at all, and I'm an armorer, so they'd complain to me.

Most civilians aren't going to abuse their guns like our M4s get abused. If the impingement guns work fine here, they'll work fine at a nice range back home, and for HD. I'd just skip the piston gun and get a nice impingement M4gery for less money.

Originally Posted by Mike Barham

I know piston uppers are all the rage right now, but all the plain-vanilla Colt impingement guns in our battalion have worked fine out here. No complaints from the guys at all, and I'm an armorer, so they'd complain to me.

Most civilians aren't going to abuse their guns like our M4s get abused. If the impingement guns work fine here, they'll work fine at a nice range back home, and for HD. I'd just skip the piston gun and get a nice impingement M4gery for less money.

Never thought of it that way...good point, thanks Mike!

-Jeff-

Mike, are you a 92Y? Which do you prefer the 20" A2 or the M4? Which do you see as more reliable?

Yeah, 92Y20 primary, secondary is 11B2P.

I strongly prefer the M4. It's a lot handier in and out of vehicles and inside buildings, the collapsible stock actually allows good shooting in IBA/IOTV, and is lighter.

I can't really see any justification for the A2 anymore. The 20" barrel is meaningless when most small arms engagements happen well under 100 yards. The A2 is decidedly less handy anywhere but the shooting range, and since it was designed by target shooters instead of warfighters, it should stay on the one-way range.

Thanks for the quick reply. Which is more reliable?

The reason I ask is that I just bought a Bushmaster XM15A2. I considered an M4gry-however I am not a full-time LEO anymore and didn't think I would need the carbine.

I was a 92Y in the Montana Army National Guard. I did a try-one after 4YR active in the USAF as a POL guy. Now I am full-time Montana Air National Guard and back in POL and part-time LEO. Just got back from "The Deid" in December.

I can't give a good answer on reliability. We only have M4s in the battalion, so I can't compare them to A2s out here.

I work very closely with our D Co., which has been in 100+ firefights since we got here. The D Co. guys report their M4s are extremely reliable and have no complaints at all.

For general range shooting, rather than mounted patrols and close-range combat, the A2 should serve you well.

Thanks Mike, I had a 20" Colt years ago and sold it when I got out of LE full-time.

I have been using my Ruger Mini-14 and my patrol rifle and really have no complaints with it. But I promised it to my son when he turns 18-now less than a year away!