Can anyone recommend the most reliable and long lasting upper piston system for and AR15.  I have tow RRA 16" and 20" rifles and would like to convert one to a piston driven river probably the 16".
Any help will be appreciated.  I don't want to build anything just buy the upper.

fknipfer1

It's hard to point to any one upper as the longest lasting.
That's mostly a factor:
- Type and Grade of barrel steel
- Barrel forging method (CHF vs Forged)
- Barrel treatment (Melonite, Chromed, None)
- BCG treatment (NiB, TiN, chromed, melonited, etc. )
... and then how hard you run your gun, how well you clean your gun, and what kind of ammo you use.

Q/C,  attention to detail and tolerances, craftsmanship and material grade are generally going to be consistently high  amongst the premier spectrum of the AR builders.
But the mid-teirs also offer quality value for dollar.

What's the intended use and how much would you like to spend, and how often do you shoot?

By far and away the best piston system on the market right now is SYrac Ordanance piston conversion kit. It comes with a piston that is captured in the low profile adjustable gas block and fits any rail system and barrel nut you can think to throw at it. I like it because it has very few parts meaning fewer failure points. My next piston system is going to be Syrac Ordanamce.

I am 75yrs of age and just would like to have a good self protection gun and maybe a little hog hunting in Texas next year.  And just want to have it so I can say I had one.

stick with a standard ar

Stop with this nonsense BS already...'15er.  

The guy asks for serious input and you give him some biased crap opinion response (when your join date is this year and you have a whopping 5 whole posts, you have no standing here) for a system that most people can't even get their hands on and that has been "available" for at most a few months, unlike years for many of the other systems.

My advice to the OP is to spend some quality time reading this Piston sub-forum.  All the answers you seek are already here.  This question has been asked a million times over the years and everybody has their opinion.

+1

You need to research also look at the some of the deals that pop up from time to time. AA has some blems for sale a while back that would not break anyone's budget. Some of the site sponsors may have crazy deals right around labor day weekend.

I am having good luck with my AA system.  I went with a 7.5 complete upper and it has shot everything I have ran through it.(Tulla and other cheap steel with no problems)  I tried the Osprey 416 kit on a 10" carbine build, and i encountered many issues with the system.  I did finally get all the issues sorted out but I just don't trust the Osprey system enough and received another AA conversion kit in the mail today to replace it with.  The Osprey kit I was having issues with was the NiB coated system, I have heard their standard non NiB coated system works well.  (I have read a couple reviews on the Osprey where peoples piston rods were sent too short and am thinking this may be my issue but not quite sure.)

All that being said, I would definitely like to try a PWS long stroke AR piston system but I just haven't gotten around to it.  Their system(on paper) looks very nice and robust.  LWRC also seems to be a real big crowd pleaser as well and rightfully so as they build outstanding weapons.  The only reason I haven't tried either of these two systems is (for me) the price point on them, the PWS seeming more reasonable than the LWRC(again to me).

Hope that helped.  

Overall however when mixing price point and performance I find it very difficult to stray from the original AA piston system.