Pistons add a lot of weight out front sending the balance point more forward making the gun seem heavier than it is. There is no gain in reliability or accuracy. Lots of claims with no basis in fact. So you spend more money to simply change how it cycles and worsen the balance of the rifle.
Piston ar shoot like any other ar15.
If you want a piston driven system get one that is designed from the ground up to be such. Scar mini14 garand m1a etc
For the same reasons that Locutus, JonM and Trip described.
I would like to emphasize that there is a lot of hype out there trying to convince folks something is wrong with the original DI design and that "new and improved gas" will correct all these problems that have plagued us for over 50 years. Of course their true intentions are more about separating you from your money.
Also you are buying into a proprietary system and if it loses the battle of the piston systems, well you'd better get parts while you can. Kinda like buying an Adam computer back in the PC shakeout days. Or HD-DVD. Remember that a firearm often is a lifetime purchase.
All good reasons and thank you all for elaborating. I am relatively new to the AR platform and understood the OP's question, but Quentin's first response did not address the question. Again, thanks for making it clear.
Are there any other reasons besides cost and pistons? (I am not considering one despite being a big Ruger fan- just want to fully flesh out the reasons why not).
Cost, muzzle weight, complexity, incompatible with millions of standard ARs, slightly less accuracy, carrier tilt, receiver extension wear, no real improvement over DI systems in 99% of ARs and I'm sure a few more I can't think of now.
I have had a Mini 14 for many years and like it a lot. I have modified it somewhat (low cost mods) and it works well for me. My AR is new to me in the last 8 months and I also like it a lot too. Different guns entirely so I don't compare them to one another. I wouldn't buy a stock Mini 14 today, but I probably wouldn't pass up another one that has been tweaked some for the right price. On the other hand i will probably be putting together another AR in the future as the parts come available to me. I would like a varmint AR (note: Its not gonna be a Ruger!)
Yeah I like the Mini-14 as far as looks and love the action. I came very close to buying one many times over the years but IMO the AR makes more sense as a new purchase. I also came close to buying a Mini-30 a few times but ended up going with a cheap AK to shoot up all that cheap corrosive surplus ammo. And instead of the 10/22, I'm a Marlin 60 guy. Ruger's having the toughest time selling me a rifle!
Well you pretty much describe the 7.62X39 rifle missing from my collection. I cannot for the life of me buy an AK, but I would buy a Mini 30 and then modify it to suit me. I just like the action on it that much better. Still waiting for a deal too good to pass up on one though. Oh, and if a deal too good to pass up comes along on an AK before the Mini 30, I guess that will decide for me.
My experience with the Ruger SR556e was the worst I've had from a new gun. Don't know the nomenclature but when I fired 55gr PMC XTAC, the BCG didn't cycle. Made my AR an annoying bolt action. Tried all 4 gas settings. Didn't matter.
Sold it to a private buyer who wanted to fix it. I know I could have sent to Ruger to be fixed for free, but that experience was enough for me to say screw the Piston-driven AR design.
This ^^^^ as a non AR owner, but prior military, is one more reason I won't get one. FOUR GAS SETTINGS!?!?
WAY more complicated than it has any reason to ever be, with no excuse that I can possibly think of.
Thanks for these intelligent posts fellas. As a guy getting more and more interested in the AR platform I need to educate myself on gas piston vs direct impingement systems. Still learning the basics of how an AR is built and how it operates. I know my pistols pretty well by now, ready to graduate to an AR soon
Any quick links for a lay person like me? I own a KelTec PLR-16 .223 pistol which has a gas piston tube and understand the basic mechanics of how that works....but the rest is foreign to me!
You will hear about how much cleaner system it is , It is really not ,the gas has to go some where so instead of it going into the action which you do clean periodically anyway it goes under the hand guard , same gunk different place and if you have a free float hand guard it makes it a PITA to clean , my buddy sold his BCM to buy the Ruger 556 because he had to have the latest and greatest and is now still trying to unload the Ruger to buy/ build another BCM . He shoulda listened to me to begin with .