At the end of March, I picked up my second AR-15 – the Colt LE6940P.  After receiving it, I cleaned it, mounted some optics, and headed out to fire a few break-in rounds and zero the optic.  A day later, I headed out for a week long vacation.  I came back, spent four days playing catch up, then headed out to Tactical Defense Institute for their three-day course Handgun I-III.  Then it was back to play catch up again, write some articles….busy times.  But I’ve been sneaking away when time permitted and spending more time with my new Colt LE6940P, and so far I’m quite pleased.

The Colt LE6940P is a brand new rifle from Colt which only started hitting the market in March of 2012.  Oddly enough, I hadn’t set out to purchase this new model from Colt – I was originally looking for the “non-P” Colt LE6940.  In Colt’s civillian AR-15 offerings, the Colt LE6920 is about as close as you can come to a government issue M4.  The Colt LE6940 is essentially the same rifle as the Colt LE6920, but adds a monolithic rail, and folding back up iron sites.

The monolithic rail on the Colt LE6940/LE6940P

The LE6940 is actually lighter than the LE6920 (thanks to the loss of the carry handle on the LE6920).  Many wonder why anyone would pay more for the LE6940 (current retail about $1500.00) than the LE6920 ( current retail about $1155.00).  I looked at this issue myself – and concluded that I couldn’t install a quality rail and good back up iron sites for much less than the price difference between the two, and you’ll be hard pressed to find a lighter (about 6.5 lbs), higher quality rail than Colt’s on the LE6940.  So that’s why I was set on the Colt LE 6940.  But Colt AR’s can be difficult to find – they seem to be snatched up as soon as they hit the market.  While I was waiting for Colt to crank out more LE6940’s, my chosen dealer got his first shipment of the new LE6940P’s.    The new LE6940P (retail about $2105.00) is essentially a piston driven LE6940 – Colt’s first piston driven model.   So I jumped at the opportunity to get one of the first piston driven Colt AR-15’s commercially available.

What’s the big deal about buying a piston driven AR-15?  Traditional AR-15’s use a direct gas impingement system – gases released when a round is fired are blown back into the chamber which is what makes the rifle cycle.  This approach sends a lot of hot, dirty gas in a critical area of the rifle.  A piston driven system essentially re-routs these gases to another area of the rifle.  There are pros and cons of each design approach, but a piston driven AR-15 will, generally speaking, run cleaner, cooler,  more reliably, and have a longer life span than that of its direct gas impingement counterpart.

The interesting thing about buying any piston driven AR-15 is that there’s no “MIL-SPEC” which standardizes the specifications – every manufacturer does their piston system just a little bit differently.   However, Colt’s not exactly a newcomer to piston driven AR’s – they’ve been working on them since the 1960’s:

The Colt back up iron sites (BUIS) aren’t as pretty as, say the Troy Industry battle sites which I put on my S&W M&P 15 , but they are functional.  Here’s a couple of photos of the rear site, both in the retracted and upright position:

Here’s a close up of the front site (in the down folded position):

One of the things you pay for when you step up to a Colt made AR-15 is magnetic particle inspection (a non-destructive testing process for detecting surface and slightly subsurface discontinuities in ferroelectric materials such as iron) of certain key components like the barrel:

Having put a few hundred rounds through it, I can tell you that the rifle shoots very well.  I had thought perhaps that the recoil on this piston driven AR-15 would be less than that of my M&P 15.  If it is, I certainly can’t discern the difference.

Here’s a couple of photos of targets from the break-in shooting I did – both targets are Birchwood Casey Shoot-N-C targets 6″ in diameter:

From 50 yards:

From 100 yards:

I was shooting good old 55 grain American Eagle ammo:

Clearly I’m not an expert marksman, but I’m signed up for several training courses this year and hope to improve.  By the same token, being able to consistently make 100 yard head shots is pretty impressive to me.  🙂

In terms of cleaning/maintenance, a piston driven AR-15, definitely runs cleaner…at least as far as the bolt carrier group is concerned:

Usually the BCG would be filthy dirty after a couple of hundred rounds through my M&P 15, but the Colt LE6940P BCG barely looked used.  Here’s a photo with the gas piston removed – a single, easy to release pin holds the piston in place:

The piston and piston chamber do take the majority of residue from firing but are simply to clean – I just wipe down the piston and run a brush and pad down the piston chamber.

Thus far I’m entirely pleased with my Colt LE6940P – as well I should be for the admittedly premium price tag, which is on the high side when compared even to other piston driven AR-15’s.  But the Colt name, legacy, and build quality are unmatched in the industry – I’m very proud to own a Colt AR-15.