M&P15 Piston System

[mag318]

I picked up my first piston system AR after settling on an M&P15ps. What I really like about this gun is the weight and the feel of it. Several PS ARs I looked at felt front heavy, the new M&P does not. Since these M&Ps come without sights I mounted a good optic on it. The only thing I don't like about it is the trigger which is creepy, heavy and super gritty, so tomorrow I'm off to the ArmaLite factory to have one of their excellent 2 stage triggers installed. I'm looking forward to shooting this new S&W to see what the difference is between this and the DI system. Smith & Wesson really makes a quality AR and it's good to see their willingness to try new things.

 

[Brett248Vista]

Ok now I am jealous!

Did you buy that "quality optic" brand new? I'm guessing it cost about 400 more than the rifle?

That is a great combo! And something very similar is on my list! I just don't know if I want to go DI or this route!

 

[mag318]

Brett, You're correct the optic costs more then I paid for the rifle. I bought a standard DI M&P15 when they came out and it proved to be an excellent AR. With everyone making piston system ARs now I guess curiosity got the best of me. The first time I looked at the piston system M&P I just liked the feel of the thing. I'll be posting a range report soon. I want to see if this is just a marketing ploy or if there are real benefits to a piston AR. I understand even Colt is building one, now that says volumes.

 

[Brett248Vista]

There are many reasons for the piston setup but from some of the stuff I have casually read, not all are created equal. I guess that applies to anything in life though.

I would love to shoot your rifle with that scope I need to start saving up because that's going to be my next purchase.

 

[mag318]

Got my 2 stage trigger installed at ArmaLite yesterday and what a difference over the factory trigger. ArmaLite has a really good gunsmith in their custom shop who does wonderful work. He spent the better part of an hour with me until we got the trigger just the way I wanted it. The only other modification I'm going to do is to add a Magpul CTR stock. The factory stock is okay and just like any other AR stock, but I don't like any wiggle so the CTR is the way to go.

 

[DavidRSA]

Got my 2 stage trigger installed at ArmaLite yesterday and what a difference over the factory trigger. ArmaLite has a really good gunsmith in their custom shop who does wonderful work. He spent the better part of an hour with me until we got the trigger just the way I wanted it. The only other modification I'm going to do is to add a Magpul CTR stock. The factory stock is okay and just like any other AR stock, but I don't like any wiggle so the CTR is the way to go.

I have the CTR on my MP15-T and it still wiggles. Not as much as the original, but wiggle it does...

 

[mag318]

The brown truck just pulled up with my Magpul CTR stock. What a difference between it and the factory stock. The thing is rock solid with absolutely no wiggle. I'm going to try to get to the range this week so when I do I'll post a range report on this new piston system M&P.

 

[460v LAC du FLAMBEAU]

Super set-up...enjoy!!

 

[ChattanoogaPhil]

I have the CTR on my MP15-T and it still wiggles. Not as much as the original, but wiggle it does...

That's strange. Are you sure you got the Magpul CTR and not the MOE? The MOE does not have the Friction Lock as does the CTR. If you got the CTR and it wiggles then I'm guessing you got a commercial size stock on a mil-spec tube? Commercial size will still fit on a mil-spec tube but it will wiggle even with the Friction Lock engaged.

 

[DavidRSA]

That's strange. Are you sure you got the Magpul CTR and not the MOE? The MOE does not have the Friction Lock as does the CTR. If you got the CTR and it wiggles then I'm guessing you got a commercial size stock on a mil-spec tube? Commercial size will still fit on a mil-spec tube but it will wiggle even with the Friction Lock engaged.

I was wondering this myself. yes I have the Commercial size CTR with the friction lock. I have a standard M&P15-T which I just assumed was a commercial size buffer tube. When I get home today I will take another look at the buffer tube using the diagrams that were posted today in the 15-22 forum. Honestly though, it doesn't affect me when using the rifle, it just bugs me (the wiggle)

 

[DavidRSA]

One other question relating to the piston system in M&P rifles.... are these systems made in house or did SW contract this out and if yes to whom?

I hope they begin to sell the piston uppers I would love to buy one

 

[mag318]

Range Report

I got to the range finally yesterday and my new piston system M&P was impressive. First of I ran three 30 rnd magazines thru it quickly to check function. The 1'st mag was LC 55 grn ball M193, the 2'nd mag was Winchester 55 grn Q3131 and the 3'rd mag was Winchester 62 grn M855. The M&P funtioned perfectly, eaiting everything and ejecting in a nice pattern to the front. Next I zeroed my ACOG TA11 at 50 yards using the Winchester Q3131, after settling down here is a photo of my best 20 group (photo1). I then shot at 100 yards and the groups opened up to about twice the size but still quite acceptable. My ACOG TA11 has the donut reticle so I was quite happy with the results. This is really a good combat scope for fast target acquisition, and though not as precise as a cross hair reticle I was easily breaking clay pidgeons at 100 yards.
All in all I'm very happy with the performance of this M&P15. The recoil impulse is different from a DI AR, to me it feels smoother and very comfortable. I fired 300 rounds this session with perfect 100% function.
Cleaning is different too, the bolt and carrier were not dirty and it was nice for once not to have to scrape off carbon build up. The gas piston is easily removed from the front to facilitate cleaning, and it to was surprisingly clean with minimal carbon. I can report that the piston system ARs are much easier to clean and maintain. Smith and Wesson did a good job with their first PS gun. And the one main reason I chose this M&P over other PS ARs was the weight. The carbine is not front heavy at all and swings easily, unlike some PS guns I looked at. The only modifications I made was the installation of an ArmaLite two stage trigger (my preference) and a Magpul CRT stock. Both S&W PS models come without sights leaving the choice up to you on what to mount. Smith & Wesson builds their M&P15s in house, the PS is a modified Adams Arms system that they licensed. This is going to be a very popular rifle once word gets out.

 

[CAJUNLAWYER]

What's the difference???? What's the advantage of one over the other??? Would the system in the Mini 14 be consodered a DI or a Piston system??

 

[mag318]

Some people will say there is no advantage of the piston system over the DI system. But owning both I can say that the piston system definately runs cleaner and requires far less lubrication. At first I thought that all these companies coming out with PS guns was just a marketing ploy, but now after having experience with one I can see the benefits. It will be interesting to see what comes out of the next series of M4 tests this fall. If the US military switches to a PS AR there will be a good reason behind the decision.

 

[Lee in Quartzsite]

What's the difference???? What's the advantage of one over the other??? Would the system in the Mini 14 be considered a DI or a Piston system??

Good question. I do know my Mini stays a lot cleaner than my neighbor's AR. He always brings a bottle of lube to the range whenever we shoot. His bolt and receiver are very dirty at the end of the day...my Mini just takes a quick wipe with a rag. The new M&P 15PS has me interested in a new rifle again.

 

[mag318]

The Mini 14 is basically a piston system with the oprod acting as the piston.