Im going to be buying or building my first AR this summer, Im torn between going with the standard AR gas system or one of the gas piston systems. I know that I want it in 6.8 with a 14.5 barrel and another upper(probably later on) with a 20 or so barrel w scope for longer range shooting. I like the standard gas system because there are a lot more options as far as uppers go, I like the gas piston system because its cleaner and it would seem to be more reliable. So what is everyones thoughts on this???
For an AR, I prefer the direct impingement gas system…
It is a tried and true system that has proven it’s reliability due to it’s simplistic nature…
It’s true that the gas rod system may be “cleaner”, however proper maintenance and cleaning will ensure a functioning weapon with the DI gas system…
I do like the gas rod system on platforms such as the M1A, AK etc…
For me, the guesswork is already taken out on these configs…
However, by all means consult the greater knowlege base here for a more learned view than I…
Just my .02…
Good luck and keep us posted…
What is your reason for wanting 6.8 for your first AR?
5.56 is going to be a lot less expensive to shoot and if you are just starting with AR’s you will want lots of practice. Now if I were shooting insurgents behind cover and Uncle Sugar is buying the bullets, I would definitely want 6.8. For punching holes in paper on my nickel, 5.56 is the way to go.
Agreed, get to know the original weapon in terms of ammo and operation. You can always upgrade the upper for caliber and or piston system. thats my opinion but you do what you feel is necessary. 
Althogh this will be the first AR that I will personally own, Ive hand my fair shair of time with AR/M16 through the use of friends rifles and for the Marine Corps. (Its great! both ways I shoot for free:cool: ) The 556 is a great round, Ive got a Remington 700 .223, and a Mini 14. I just figured I would start out with the 6.8 I have not dought that Ill have an upper in .223 @ some point. If this was my first experience with an AR im sure I would get it in .223 because of the cheap and plentiful ammo.
Isn’t 6.8 SPC about a dollar per round?