I have read multiple posts on here where people advise against getting a piston AR. Why is that?
My brother in law has a Robinson Arms XCR and I absolutely love shooting it. Most of the things I have read say that piston AR’s are the way to go.
Am I missing something?
If you have read the various posts then you should know. I am not for or against it per se. Simply that the issue has been discussed on both sides.
If you like a proprietary design that may or may not have limited parts availablity as well as the necessary support network then by all means get one.
What do you think is wrong with the original? An answer on that might give us an idea where you are coming from.
Pistons guns are GTG. The AR15/M16 wasn’t designed to use a piston. Piston operated AR15’s have a different/greater recoil impulse. They suffer from bolt carrier tilt leading to wear of the receiver extension. The piston adds weight and degrades potential accuracy. They offer no greater reliability than a properly maintained DI gun. The only real benefit is that their easier to clean and work well with sound suppressors.
I have an XCR and I’m very enthusiastic about it. I also have an LMT piston gun and I’m very enthusiastic about it. I have a piston upper for the aforementioned LMT and I am enthusiastic about it. Nevertheless, I prefer the piston.
I have read multiple posts on here where people advise against getting a piston AR. Why is that?
I think… my opinion… I have no research or data to back this up… I think a lot of the fireworks about DI versus piston is purely emotional. Some rational and good points are made like parts availability and support. Other points like how the gun feels when you shoot it are purely subjective. Other points like the fact that the AR was not designed to use a piston are irrelevant. There is often considerable emotion accompanying the arguments. I expect to get a thrashing or two for saying this. Just my humble opinion folks.
Why not a piston AR? Pick up the next issue of Combat Tactics to read my take. 
ETA, I was asked to elaborate, which I obviously can’t do too much for copyright reasons, but the short list is
[ul]
[li]Carrier tilt
[/li][li]Proprietary parts
[/li][li]Incremental improvement
[/li][li]Turd polishing
[/li][li]Higher cost
[/li][li]Increased weight
[/li][li]What’s the advantage?
[/li][/ul]
The article will expound on all of the above.
Because quality DI AR’s run nothing short of superb if properly maintained, often in the most simple of ways.
Because replacing a SS gas tube with springs, operating rods, and pistons with clamp on blocks is introducing more parts needlessly to a system.
And there’s the carrier tilt battle. They just create many more issues than they solve.
Becasue H&K’s cost too much! 
Right up to the point that you crack the upper receiver.
I think the piston system on a AR is not needed. Do they work yeah do they make it a better rifle in my experince no. Yeah it takes alot of the heat and carbon out of your receiver but it transfers all that heat and carbon up to the front so is one better then the other depends on who you ask. Ive never had a problem with the my DI ar or m16 when i served. As long as you take care of the rifle you have nothing to worry about, so ill be sticking to my DI
In my mind, it’s just a matter of cost:benefit ratio.
EXAMPLE: Keeping it to uppers that are more or less analogues of each other, less the operating system.
A top-tier carbine-length DI upper (albeit marked as a sale price item): $749.
http://www.bravocompanyusa.com/Noveske-N4-Light-Carbine-Upper-Receiver-Group-p/n4%20basic%2014v%20urg.htm
A similar LWRC upper: $1295
http://www.lwrci.com/p-19-m6-556-upper.aspx
Even for a hard-use gun, the difference in performance and maintainability between the two is statistically insignificant, so why spend the extra scratch for no palpable benefit?
UNLESS!!
…you’re doing any two of the three following: SBR, full-auto, running a can.
Some would say any one of the three, and I see the point behind that logic, if it presumes no-shit high round counts.
If you’re NOT doing any of that stuff, the piston arrangement provides no realizable benefit, so it ends up being a judgment call on the part of the buyer as to whether or not they can afford it. Assuming that they can, and given the costs of support equipment ( ammo, training, range memberships, tactical rubber duckies, chow, morale patches, etc.), I have a hard time justifying the investment of resources being concentrated primarily in the gun alone.
You can do a lot with +/-$500 in extra money spent on stuff that feeds your gun and skillset instead of on the gun itself, unless you’re getting something out of that difference.
Or, unless you have Scrooge McDuck money and a burning desire to take advantage of our wonderful free-market economy. It’s all good, I just feel that it’s a question of how you want to spend your dough.
for me. it’s more parts to break. the DI worked so why bother?
IIRC, no XCR has yet survived a EAG tactical carbine class w/o failure.
As Pat would say, this is a clue.
Dude, I think if you want to buy a piston gun then go for it, yeah you can have problems with carrier tilt(believe me I know) but that problem can be fixed. I know and believe whole heartedly in the old saying " if it aint broke dont fix it" but its something new, I have had many different AR’s some piston and some DI, they all worked fine, and so what if you buy a piston upper and hate it… sell it, there is a market out there for them, and buy yourself a DI upper
IIRC, no XCR has yet survived a EAG tactical carbine class w/o failure.
As Pat would say, this is a clue.
Why haven’t they survived? Where’s the AAR’s?
:eek:
Haven’t heard about that yet, could you please explain or link for those of us out of the loop?
I had previously been operating from the position of “pistons somewhat make sense when non-constant supression is involved”, I wish to know if I should revise that position.
Figured this was a decent place to throw this in…
Anyone tried out the Sig 516? Are they going to live up to the hype of “refining the Piston AR”? I have a hard time saying that Sig will mess it up, as they don’t tend to do that sort of thing much…
Does anyone have experience with both the 516 and 556 models, and what, if any, are the greatest changes to the platform swap? Obbviously it’s an M4 platform where the 556 was not, but what will make or break the 516’s?
I have absolutely nothing against piston guns, but have no love for a piston AR. Big difference.
Guns that are built around a specific operating system do not do well when people try to stick other operating systems into them. They are built to work a certain way, with specific clearances and tolerances, with specific parts sizes. If you want a piston gun, go get a piston gun. I am not going to say that Direct Impingement is better than Long or Short Stroke Piston/Gas Tappet Operation, simply that it is better in an AR. Lots of us bought into the piston AR when they first hit, but long term use and data collection has caused serius doubt as to their necessity, even when it comes to the “two of the three” rule.
My XCR is 6.8 and I have about 50 rounds thorough it so far and until I am reloading again there won’t be many more. My impressions of it are based on examination not so much shooting.
[QUOTE]IIRC, no XCR has yet survived a EAG tactical carbine class w/o failure.
[/QUOTE]
What happens to them?
My LMT was purchased as a piston gun and didn’t cost a lot more than DI. I would would not add a piston kit due to the cost. Karl Lewis, asked why he offered a piston gun had a straightforward answer: “customer demand”. This argument kind of reminds me of debates years ago over Weatherby rifles. Pretty, shiny, super powered, some folks liked them, some folks (me included) loathed them.
“two of the three” rule
What is the two of the three rule?