So, I got a buddy who wants me to sell his SHTF upper for him because he has to have a new piston AR.
Because he has more money than sense & he has to be on the bleeding edge of technology no matter what it is.
So, I have been doing some research for him, because he has more money than firearm's knowledge as well.
So, after doing some reading, some comparing and taking a short drive to a store that had one, I found this kit that is pretty damn impressive actually.
AR-15 Gas Piston Systems
This kit is pretty slick because just about anyone can install/remove this kit in just 10 or so minutes once you know what you are doing.
It comes with a replacement bolt carrier, and you do need to do is put your chosen bolt head in place ( in case you were shooting 7.62 x 39mm for example ).
The gas interface system bolts onto the barrel, underneath the handguard, and then the piston goes through a hole in the upper and mates up against the new included bolt carrier that has a nice flat surface in place of the gas tube interface.
This is impressive because a lot of the kits have a "bolt on" piece that you replace with your bolt carrier. With a lot of hammering of sustained fire, an improperly staked piece could come loose and fail.
The kit costs like $400 ( your local prices may vary ) but if you absolutely HAVE to have a piston system, this kit is well made and will allow you as an end user to upgrade your existing AR upper without much trouble at all.