A little background.  I have been a huge Sig fan since I picked up my first P226 (West Germany).  I bought a M400 when they were first released because I am comfortable with the DI gas system.  Comfortable meaning that I have spare parts and could repair it on the fly if necessary.  So I was in the LGS and surprisingly they had a P516 10" and P716 12", both with the SB15 Stabilizing Brace.  I could not believe the quality and the feel of these pistols.  Before someone responds and says buy all three, I can only afford one.

PM400 11" SWAT PSB
PRO: I like that it is DI and 11"
CON: I don't like the rail and the FSB

P516 10" PSB
PRO: I like the rail
CON: 10" and it is Piston (Not that piston is a bad gas system, just that I would need to send to Sig for repair.)

P716 12" PSB
I like 7.62x51mm, but I can not imagine the noise, muzzle flash, and recoil.

There is very little info and almost no reviews out there since they are fairly new, so has anyone had some experience they would like to share?

P716

Hello Precious!!!

I'm going to get a P516 in a couple weeks. I want a piston gun, fold down front sight for my TA44 1.5x Acog, and a gun that will take ammo & mags that are the most commonly used. I just about walked out of a gun shop on Saturday with one. It took some self control not to whip out the credit card. Promised the wife I would sell an old toy before buying a new toy. Damn, now I have to go thru the toy box and find something I can live without.

Go with the PM400. DI is fine as long as you keep her lubed and cleaned once in awhile. Piston is heavy, sharper impulse (recoil), more expensive and like you said, lack of parts. As far as the FSP, you can change it out if it bothers you.

I've always found my 10" 516 to be very smooth, despite the piston recoil.

Why ?

Can't speak for piston vs no piston but the M400 looks like you could swap out those rails very easy. So if the rails are your only complaint...get rid of them.

Why not?

It is my understanding that it is a proprietary piston system.  If something breaks, I would need to send it in to Sig for repair.

Or you get the parts from Sig and do it yourself...

Yeah, it's not hard. I'm not sure what parts would seem to be difficult to work on.

Aren't all the 308 piston systems pretty much proprietary?  I didn't know there was a standard.

Doc

I'm patiently waiting for Sig to offer the 716 pistol upper by itself.

Hopefully my form 1 will clear for my 716 Patrol lower about the same time.

Has anyone else done this?