Model 8 Piston Carbine

Stag have not released much information about the rifle. It looks much the same as their M4-style Model 3 carbine. I am not sure if the piston system is their own design (if you can identify, please do in the comments). It looks like it could be a long-stroke design, but I am not sure. UPDATE: See below.

Piston system can be seen when upper handguard is removed.

Specifications
Caliber	5.56mm NATO
Upper	Forged and Mil Spec
Operating System	Short Stroke Piston
Sights	Midwest Industries Front & Rear Flip Sight
Barrel	16" Chrome Lined 1/9 Twist
Magazine	Standard AR-15
Stock	6 Position Collapsible
MSRP (Price)	$1,145 (standard model) and $1,175 (Model 8L left handed)
Availability	December this year.

Lefties will be pleased to see that a left-handed model will be available.

UPDATE: David from Stag told me that it is a short-stroke piston that Stag Arms designed.

The new Adams Arms gas block quickly mounted with hex screws and a new bolt carrier key, a couple springs and a bushing were all that was needed before adding the sleeved drive rod. Supplied front handguards mounted normally, and I was left going back over the installation manual, convinced that I must have missed something. It was that easy. Though it took me more than half an hour due to the troublesome factory gas block, this is certainly a task that can be accomplished by a moderately capable gun owner.

It is a well written review and worth reading.

This 3D animation shows how the piston system works verses the AR-15’s normal method of operation, direct gas impingement.

M&P15 PSX

The only difference between the PSX and PS is that the PSX features a Troy 7″ modular quad rail handguard.

M&P15 PS model and Piston Operating System
Photo ⓒ Remigiusz Wilk (REMOV). Used with permission.

Specs:

Barrel Length: 16″
Barrel Twist: 1 in 9″
Overall Length: 35″ Extended/32″ Collapsed
Stock: Collapsible 6-position
Weight: 6.5 lbs.
Finish: Hard Coat Black Anodized

I do not know the MSRP on either model.

It is a pointless comparison. Obviously Stoner did not design the AR-15 platform to be fired waterlogged. If he had it would be piston driven. Still, it is interesting to see what happens.

H/T: MP.net

Many of the improvements Colt have developed have been applied to all these guns, I won’t list them all, click the links to read the full details.

Colt Sub-Compact Weapon (SCW)

A 5.56mm 10.3″ barreled sub-carbine/PDW featuring the new Colt side-folding stock. It is able to use an upgraded gas impingement system or the Colt Piston System (CPS)

Side Folding Stock. Photo by SMGLee.

Colt ACC-M (Advanced Colt Carbine-Monolithic)

This is basically an upgraded M4. It features many small improvements over the M4A1 and Colt’s new monolithic rail system. If it was adopted it I think it would probably be named the M4A2.

Colt Advanced Piston Carbine (APC)

David calls this the HK416 killer. It utilizes the Colt Articulating-Link Piston (ALP) system.

Colt Advanced Hybrid Carbine (AHC)

This carbine features a hybrid gas impingement and gas piston system. I am very interested to see how that works.

Colt Infantry Automatic Rifle (IAR)

I covered this a few weeks ago on the blog. It is a light machine gun and Colt’s entry into the Marine Infantry Automatic Rifle competition.

Colt IAR. Photo by SMGLee

Thanks Jennersen!

The rest of them are here.

14.5″ version

They achieve this by plating the upper receiver with silicon nickel and chroming and heat treating the bolt and carrier.

Upper receiver

Here is a video of it in action

In spite of its name, it is chambered in 7.62X51mm, not .308 (yes, there is a difference).

More info at POF-USA and Defense Review.