Piston'ed AR vs. Robarm XCR

[keitharsis]

Have been eyeballing the new XCR for a while now and can't wait to hear from the people who have pre-ordered theirs to give their range reports and other critiques of the rifle. Seems like ROBARM has addressed several issues of the AR system and made improvements.

I all but wrote off an AR from my wish list until I started seeing the new breed of Piston'ed AR's coming out (DSA,KKF,POF,Leitner-Wise,Z-M, etc etc). Now I am flirting with the idea of doing an AR build and buying a pistoned AR upper.

Crunching some numbers it seems like either idea will be costing about the same so I don't think cost will be a factor in my decision. What do any of you guys think? Any pros/cons for me to think about?

 

[ak47nevada]

Hello keitharsis.

I don't intend at all to slam Robinson Arms but I do recall reading almost one in a half years ago how they were going to release a .308SLR in the beginning of 2004.

Who knows when they'll release the XCR-L. The lack of updates on their website is annoying. Latest update being December 08 "going to be released really soon."

I'm not getting my hopes up.

My two cents.

 

[MatthewVanitas]

You know, I was _this_ close to just settling on a standard M4gery

After considering basically every post-1938 semi-auto under the sun (M1, M14, MAS, FAL, G3, Daewoo, ad infinitum), as well as the quirky custom pieces, I had almost settled on just a standard M4gery. I figured tons of folks who shoot way more than I buy AR-15s, so it can't be that bad.

But now it seems _everybody_ is making a piston-driven version of the AR series. There's the C.R.O.S. by POF, Kurt's Kustom Firearms, HK's look-but-can't-touch upper, DSA's "gas trap" AR, the AR-180B, the XCR, etc.

--The XCR seems extremely cool, but Robinson seems to have a rep for wishful thinking. Still, that folding stock is very iwannacoolgun, and seems like a pretty practical design overall.

--AR-180B would be cooler if they put a little more effort into it, but it seems like more of a recreational piece, at least in Armalite's eyes.

--Regarding all the other slightly-modded piston ARs, I'm really drawn to the fact that they share the vast majority of their parts with the standard AR. However, concerned that there is no one, standard way to piston an AR, thus each shop has their own piston-parts, plugs, handguards (?), etc.

Still thinking I might just bite the proverbial bullet and buy a standard AR, probably the RRA Entry Tactical (super sweet). Of course, seeing how much I've vaccilated on the subject, by the time I escape California I may well have decided that the PTR-91K (G3 ripoff) may be the ticket. Ah, the very cool and somewhat impractical collapsing G3 stock...

I was going to start my own thread IRT the numerous piston-op ARs, but this thread seems to cover it amply. I await with great anticipation the public's reception of the XCR, DSA, & Co. -MV

 

[keitharsis]

Hopefully people will slowly but surely start to get these new pistoned AR's and we will start seeing threads with their reports. I'm actually surprised it took 40+ years for us to finally start seeing this improvement on the AR. Now the market seems to bombarded with this new fandangled upgrade LOL.

 

[cgv69]

While I haven't priced it out it seems hard to believe you could build a piston driven AR for the same or less money as an XCR?

Regardless though, let's assume they will both cost exactly the same... The XCR still offers more advantages than a PDU AR. Monolithic top rail, quick change barrels, slightly improved ergonomics. The down sides to the XCR is that ROBARMS's track record is a little shaky. I know I will not buy an XCR until there are a number of field reports from independent sources verifying that it's reliable but than again, none of the PDUs have really been tested that much either. The other down side to the XCR is being a whole new system, parts and accessories will not be cheap or easy to come by.

I don't know but at this point I'm leaning XCR? (especially in SBR form! )

IMO, if you want the absolute ultimate that would address just about any concern anybody has ever raised it would be...

L-W PDU components...

Married to a LMT MRP upper (I have read that this should be possible but nobody has tried it yet that I'm aware of?) ...

and the icing on the cake?...Chamber it for Remington's 6.8MM SPC

On paper this is a possibly but like I said, nobody has done this yet that I am aware of. Even assuming it can all be done and work flawlessly, it would be one very expensive carbine and I think pretty hard to justify, price wise, over a standard M4.

Just my $.02

 

[Kaylee]

I'm actually surprised it took 40+ years for us to finally start seeing this improvement on the AR. Now the market seems to bombarded with this new fandangled upgrade LOL.

It didn't take us 40 years. It was tried in the 80's to (afraid I don't recall the name, but the patent docs should be over at uspto.gov). It failed 'cause no one bought it. The AR works fine as it is.. if a piston system makes you feel better about the rifle, have at it. But it's not a problem.

Actually, I'd be much more excited about the left-hand charging handle and full length standard rail on the XCR than a changed gas system. Both look like nifty improvements!

Heck, if the XCR was already on the market and I wanted an EBR, I'd be lookin' pretty hard at that one. Given that it was apparently designed for the SCAR trials (and I'm kinda surprised it lost -- looks like it has it all over the FNC variant they approved), it's got a nifty feature set. And Larry C says it actually works, right?

(Out of curiosity Correia -- how does the weight and handling compare to a comparable barrel length M4?)


-K

 

[keitharsis]

CGV69- From what I've seen the XCR's seems to be priced in the approx. 1200-1400'sh range. Piston Driven AR uppers seem to be just under
1000 (POF) , to just over 1000 (Lietner/Wise) . With a lower lower build of around upper 100-200 range the prices do seem to at least be similar.

The XCR seems to want to be as interchangable with AR parts as possible, but like you said, there seems to be a few proprietary parts as well that availability might be a concern.

 

[cgv69]

Hi keitharsis,

I think we need to make sure we are comparing apples to apples.

You can not build a AR lower for $100. A Stripped lower alone will cost you ~$100. The cheapest I've seen was $80 but you had to buy multiple lowers for that price. Decent LPK's are generally ~$55 and if you look around you could probably find a complete A2 fixed stock for $50. To keep this as a far of a comparison as possible, your lower would need to have some kind of collapsible stock. (excluding lower than normal gunshow\my buddy sold me type deals) it is unlikely you will build a decent quality AR lower with a collapsible stock for much less than $250.

I could be wrong but I do not believe any of the PD AR uppers come with any kind of a FF rail system for the $1000 you quoted so you would need at least another $250 for one of those to try an compare equally to the XCR.

You are now at $1500 for a complete PD AR and you don't even have any sights yet. Robinson Arms currently lists the price of $1249 for a XCR-L

So I still think, if you compare apples to apples (as much as possible) the XCR is the less expensive way to go. Even still, as I mentioned above, assuming the cost was equal, you would still be getting more with the XCR. Monolithic Rail platform, quick change barrel (which also means quick caliber changes), and better ergonomics.

If the XCR can prove it is reliable and reasonably accurate, I think it will be the platform all others are measured against. Time will tell I guess?

Again, just my $.02

 

[ETCss Phil McCrackin]

I read about the RROC Conversion for M4s in 2003. Does anyone remember or know what became of that? It seemed like a pretty good idea at the time.

 

[Harry Tuttle]

in order to not bind the piston rods function
the gas trap ARs seem to need a very stiff heavy barrel
http://www.pof-usa.com/AR15/AR416upper.htm

the LW unit is prolly made of the same vaporware as the 1999 LW 22lr upper

 

[rock jock]

Seems like ROBARM has addressed several issues of the AR system and made improvements.

I have to ask, and I don't mean this as a slam, just a simple question - have you ever owned an AR or are you just relying on Internet gun forums to decide that it has "issues?"

 

[keitharsis]

Now that I look at it your way you are right cgv69, XCR= more bang per buck. I just keep trying to talk myself into sticking with an already proven system aka: AR. Not only is the AR been around long enough to know it's a system that "works" but it has been around long enough that aftermarket support is abundant and peoples knowledge of the system has been honed to an art.


And to answer rock jock-- No I have never owned an AR so I am only going by hear-say. Be that as it may, there is no question that the AR system does crap where it eats.Now does that make the system unreliable? Maybe not, but a piston system is no doubt a cleaner system.

The other anecdotal "weak links" of the AR like extractor,gas key,gas leak, and bolt group issues, have seemed to be also addressed by Robarm and the XCR .I say anecdotal because it is indeed only what I've "heard" or "read" about and not have actually experienced.

 

[MrMurphy]

If you keep the AR reasonably clean it'll work fine. I've got thousands of rounds through ARs including about 600 through a M16A2 in simulated combat conditions (heavy rain, dirt, mud, gunk all over the rifle) running a couple combat assault courses at Fort Knox when I was a ROTC-ite.

Discounting blanks (which don't have enough gas to make it work all the time) i've never had a jam that wasn't self-induced (fingers over ejection port bouncing an empty back in) or bad-mag or bad-ammo related.

 

[ktd]

MrMurphy-you a Camp Challenge grad?

I have used the M16 and M4 in desert conditions and found it to be okay, (conversely there were times when I had a crappy AK and got that to jam (sand in the mags)). On the whole though, pistons like my AR180 are just a lot nicer to clean, so as a shooting gun that is a nicety. My buddy will probably pick one up, he is all so excited about the concept.

k

 

[Zak Smith]

The LW piston WILL WORK on the MRP.

The LW piston has been tested favorably the military.

LW has a MRS to be released in Apr or May, which will be identical to the MRP except:

1. it can come from the factoty with a piston barrel
2. it requires no tools to switch barrels
3. it can use a standard AR barrel
4. the side rails are modular

 

[Bartholomew Roberts]

First, I don't necessarily know that adding a piston to an AR system is an improvement. Like most elements in engineering and design, you are trading one problem for another. This thread from lightfighter.com has some good, informed discussion on some of the limitations of piston-driven ARs and potential problem areas:

http://lightfighter.net/eve/ubb.x?a=tpc&s=7336015661&f=7206084761&m=881102668

I think the main reason you are seeing a spawn of piston-driven ARs is that the requirements for the SCAR system specified a piston-driven weapon and many manufacturers thought an AR derivative would have an edge over an entirely different system.

Second, Robarms hasn't had the XCR out for a long time; but they have spent some development time on the M96 and RAV-06 weapons that should carry over nicely to the XCR. The XCR was their entry for the SCAR competition mentioned above.

They official reason they were dropped from selection because they failed to include all of the equipment necessary to conduct testing of the firearm (rumor has it that they failed to include a BFA - although the XCR uses the same BFA as the M16 series). I suspect the unofficial reason probably has to do with concerns over whether a smaller company like Robinson Arms can produce the necessary number of rifles if they got the contract; but that is just speculation on my part.