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Discussion Starter #1
First off, I don’t mean any of this as criticism. I’ve gone on record as saying that in my opinion the XCR is one of the largest steps forward in a very long time – and I stand by that statement! That having been said, here are 10 little touches. Just things here and there that I’d like to see, that would make it a bit more user friendly in my opinion.

1. Lighten this weapon. As-is, she’s about the same weight as an M4, which I don’t like. Dropping a pound to a pound and three quarters would be IDEAL. I view 6 pounds unloaded / naked as a ‘perfect’ mark. Not that a reduction to exactly 6 pounds would be possible, but the closer the better.

2. The barrel-retaining bolt had to go. I use the front of the magwell as my forward grip, and that bolt head worked over my first finger. Heck, the guys showing up to the CQB course with vertical grips all tossed ‘em or weren’t using them by not that many days into the course – they were going to the front of the magwell too. I say “had to go” in the past tense because I found a good alternative, so I “modded” mine. Had to purchase a bag of 100, so anyone wanting to do the same can drop me a note and whatever a stamp costs – I’ll send the part.

3. The sling attachment point on the rear of the receiver should change too, although I’m not positive how to change it ‘for the best’. I’ve battered the heck out of my sling snap with the rear of the oprod. What I came up with works fine, but the sling isn’t quick-detachable from the XCR any more. Moving that point would be nice – or something else.

4. And speaking of sling attachment points, there’s no provision for attaching a standard 2-point sling at the rear for precision shooting. As in there’s no sling swivel at the toe of the buttstock. I had my machinist fix that, now mine has an M16A2 sling swivel at the butt, and it works GREAT! I know it’s a carbine, but that doesn’t mean I don’t like using mine at mid (400 to 600) ranges. And yes, from a good prone, hitting pepper poppers at 400 is almost too easy.

Note: Don’t take this as I’ve proven either 5 or 6 really need to be done – at least not yet. Last year I got sick during the harsh winter, and never got to put the XCR through the –40 testing I had planned. Hopefully in another month or so, I’ll have some experience in this matter (I’m planning on it) and can say whether I could make it malf in the cold and wet. Subsequent to that, it’ll get to play in the sand before slogging through the Oklahoma mud in June.

5. I’d like to see some lightening cuts inside the upper as well – in the cylindrical part that the carrier rides in. The way I see it, part of the reason the FNC did so well in the sand and the arctic was because of the ‘slop room’ for sand and ice to get around in within the upper. Since the XCR is a derivative of the FNC, it would only make sense. I’m thinking something along the lines of narrow grooves cut into the upper, so that it looks a bit like the chamber of an HK roller locker. That way there is still ample surface area for the carrier to slide on and lots of strength, but lots of ‘goop room’ as well. Not that the flutes need to be all that deep or anything. I can’t help but believe the ‘goop room’ of the formed sheet metal upper that made the FNC work so well also is part of the reason the Kalashnikov has such incredible reliability... Or looking at it from the other direction, when water gets between the carrier and the upper, I can’t see it taking much to essentially ‘ice weld’ the carrier in place. Lots of close surface area between the carrier and the upper. The flutes would reduce that surface area dramatically.

6. And just out of curiosity, why were the driving bands on the prototype bolt carrier done away with? That was absolutely ingenious in my opinion – something I’d like to see brought back. Same reason as the above.

7. If I could, I’d like to have a bolt that would be easily disassembled – without tools preferably. It’s probably just me, but I like being able to run a pipe cleaner in the firing pin channel, and wipe down the pin itself. Especially when going into really cold areas. Yes, the spray type degreasers work well enough, but I prefer to do it manually so I just KNOW it’s right.

8. If I had my preferences on stocks, I’d opt for a fixed synthetic type, with a short length of pull. Something with a compartment for cleaning stuff, so I can get rid of at least some stuff in one vest pouch. On the AR, I prefer a Sully stock – and yes, I had my ‘smith wallow out the inside of that too – modified with an A2 buttplate for the trap door. When the initial ‘modified 96 stock’ idea didn’t work out, I cuddled my M14 for days (GRIN). If nothing else, a mount similar to the one for the M4 type stock – except it would accept a standard A1/A2 buffer tube. Then I could twist that one out, put the shorty tube in, and run a Sully stock!

9. Iron sights! Not that I think the XCR should come with them – I think it’s a TREMENDOUS thing that it doesn’t! Here’s the thing though... maybe it’s my face, but I’ve always come up “low” on the sights when using an M4 / CAR type stock (which is a good portion of why I like the fixed stocks!). The tubular stock on the XCR is the same thing. To fix that, I use the lower LaRue Aimpoint mount – it centers at 1.140” off the deck instead of the traditional 1.410” off the deck. As far as BUIS, nobody – and I mean nobody – makes anything but 1.410” centered stuff. Something a bit shorter would be ideal. There are shorter fixed iron sights, but not BUIS – I’d LOVE to see RA making some of them! One request though – I like my Trijicon front sight blades, so please make ‘em so that they’ll accept the Trijicon blade.

Note: Of course, the fixed synthetic stock might bring my cheek up high enough I don’t need the lower optics and such – that’d be a simple fix! HA! Thinking of this, Alex, are you going to have some different stocks and BUIS on the XCRs at the SHOT show? I’d LOVE to be able to try before I spend more money LOL!

10. And lastly, something I’m going to officially term the Jack-a-dot. This would be a REALLY simple modification to the right side of the bolt carrier. This way one could easily swipe a finger over the carrier, through the ejection port, and feel for a divot. If the divot was positioned towards the front (say a hemispherical divot centered on the radius of the front of the ejection port) of the carrier where it should be, the bolt is known to be fully forward. A purely tactile way of doing a chamber inspection. As I said, I use the magwell as my forward gripping surface – pivoting my finger around slightly allows me to feel the carrier through the ejection port at the most forward position. But the carrier goes so much farther forward than the front of the ejection port, if the bolt isn’t in battery by a significant distance, I still can’t feel the front shoulder of the carrier through the ejection port.

Just some things to think about – congrats on successful production of such a tremendous design!
 

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Discussion Starter #2
Question was asked about the mod on the barrel retain bolt.

Essentially, I purchased the same thing but with no cap. This one fits flush with the receiver, and accepts a hex wrench to loosen / tighten. Works the same as the stock cap screw, but a different size hex wrench.

I'll post a pic when I can get someone to work the danged digital camera for me.
 

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I asked Alex the same thing last Aug about the retaining bolt. He said he was meaning to order the bolts without the head (recessed) but hadn't gotten around to it. I guess not too many people have asked about it. I think you have some good recommendations, check out this little sling thing, it allows for many differet mounting configs and doesn't get in the way of the charging handle (though it does lay against my cheek).
http://www.blueforcegear.com/product.cfm?type=cat&cat_id=5&prod_id=81
 

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Great write up! Thanks.
 

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Discussion Starter #5
Aziator, thanks for the reference!

It appears I did something very similar. Here's the link for the hardware, which can be ordered painted. The tan didn't exactly match, but oh well ;D

http://www.strapworks.com/Reducing_Loops_p/mrl.htm

Taking that, and a piece of paracord that loops to about 2", throw the loop through the cordage point on the hardware and double it through. Then put the free end through the sling attachment point on the XCR and bring the hardware back through the loop. After that, it's just a matter of feeding the sling through. And since I just happen to prefer the T-I-S single point slings that are 1.5" wide......

The only real downside is you can't just unclip and drop the weapon. Since we don't do waterborne ops in the high desert though, I call that "acceptable loss" and drive on :)
 

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The only real downside is you can't just unclip and drop the weapon. Since we don't do waterborne ops in the high desert though, I call that "acceptable loss" and drive on :)
Well there was this one time west of Karbala that I thought we might need some overwater stuff but it ended up OK...

The only thing I don't like about the look I have is the length, it is like adding 6 nches to the sling. Luckily the place I got it can rectify that. I should have a new shorter one this week. That along with the QD mount up front allows for pretty quick detachment.
 

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nice write up. here are my thoughts on a few of your ideas:

I can't see anyone complaining about weight reductions as long as they don't compromise the rifle's durability.

I think the roll pin holding the fp in the bolt is sort of a pain, but it's a simple robust system so I can't really complain.

what are driving bands?

I inquired about a recessed barrel change nut when I ordered mine as well, but I like my foregrip so it was mostly an afterthought...

as far as slings go, part of the reason I went with the follapsible magpul ctr was for ease of sling setups. mainly because I don't like single points and wanted to be able to easily run a vickers 2 pt.

as far as the xcr's cheek weld relates to the irons and optics, I think it's more economical for both robarm and us to just use height adaptable stocks and optics mounts than for them to develop their own xcr specific buis. Before I had the rifle I thought I was going to need a chin riser or really low mount for my aimpoint, but I now prefer the cheek weld of the xcr to an ar-don't need to scrunch my big melon down into the stock ;). I use troy buis and the middle height spacer on my arms mounts for an exact cowitness setup.

 

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That's exactly how I set up my XCR, minus the foregrip and flash suppresser, an plus the 1/2" riser on the Magpul stock.

Isn't the GG&G bipod great? I think it's well worth the extra bucks for such a light and solid bipod.
 

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Discussion Starter #11
Sorry....

Driving bands: on some bullets (BIG bullets) you don't want the whole surface area of the bullet in contact with the rifling or bore. The way they do those is by putting driving bands on the bullet.

Imagine a cylinder 4" long and 1" in diameter (just as an example). Now, a half inch from either end, put "bands" on that cylinder that a quarter inch thick. So the diameter of the cylinder where the bands are would be 1.5" - the rest of the cylinder would be only 1" in diameter.

That's how one of the early bolt carriers was built - driving bands fore and aft on the carrier itself.

The end result was that the part of the carrier in contact with the upper was only at the bands. That not only reduces friction due to riding on less surface area, but also gives grit and garbage a place to live without binding up anything. The driving bands also act as scrapers, cleaning the area they ride over instead of just grinding it into the two surfaces. Rubbish scraped around winds up leaving the 'intense' area, and dropping into less problematic areas, eventually out of the weapon (assuming you dope 'em up BIG TIME - like dropping a handfull of sand or two in the action).

And if you think I'm exagerating about a couple of handfulls of sand, I'm not - the Kalashnikov took more than that to fail.

So I got with Ty today, and asked a silly question. All this time, I thought the M4 stock adapter would be exactly that - something to put an M4 stock on with. I have no use for the M4 stock, and not enough experience with some of the aftermarket variants (other than on the AR chassis obviously) to comment on them. No thanks.

Ty said I could twist a standard buffer tube on there, so I ordered one. My thought is that I can put an entry stock, or a Sully stock, on there and the increased diameter over the tubular stock should raise my cheek the quarter inch needed to change from the 'low' 1.140" LaRue mount to the 'normal' 1.410" LaRue mount. That'd sure make BUIS cowitness and procurement easier! ;D

This would make #8 and #9 drop off my list as irrelevant. Again, I'd like to draw attention to the fact that this is an attribute of my physiology (those high Native American cheek bones) and not a problem with the XCR.

Additionally, with a good sling adaptor plate on there between the stock and the receiver, that'd remedy #3 on my list, and #4 would be moot.

Gee, a $65 expendature and 4 out of 10 recommendations might drop off the list! HA! We'll see - I'm guessing delivery should take about 1 day - if I put it in Thursday, I can live-fire the new set-up this weekend (yes, I just happen to have those stocks on hand) ;D

Oh, and by the way, I ran across an old thread where a troll was talking smack about the LaRue mounts on the lightened XCR rail. I guess I'm just a dumb-o (and obviously so are the instructors at some top-flight schools across the country) but I've run mine hard and it's still 100%. But then again, Mark LaRue said it would be.
 

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Discussion Starter #12
A question about the M4 stock adaptors and such, if I could.

I'm whipping up another order at Brownells, and started to add another of those DPMS (there are only two places that make these out of steel, DPMS is one) sling attachment plates that attach at the rear of the AR receiver, between the receiver and the stock.

My thought process is that when Terra gets my XCR stock adapter out to me (thanks Terra!) I'm going to mount an Entry stock (some folks call 'em "stubby stocks") on my XCR. Alex swapped me a shorter tubular stock - the 'standard lenght' folding tubular stock was a touch too long for me. It turns out the Entry stock (I put an A2 buttplate on mine) is almost perfectly the same length as my shorter XCR tubular stock. Good deal.

But if I put that DPMS sling attachment plate on the buffer tube, then slide the Entry stock on...... can I attach my sling to the plate and it not interfere with the charging handle?

As I mentioned before, the "trigger snap" that attaches my one point sling to the standard XCR attachment point, has gotten battered because I used to catch it with the rear of the charging handle - before I figured out the 'sling thing' trick.

I'm just wondering if moving the sling to that plate will solve that completely or not. Has anyone tried that?

Thanks!
 
J

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I like a lot of those ideas, and dont think that it's out of the realm of possibility to see them put into production. I really do think that it needs a QUICK, NON-VISUAL, chamber check method. I dont know if the jack a dot is gonna cut it (although i like the name) as it only indicates whether the bolt is forward or not. My thought would be to have a indicator A'LA the new glocks where it is slightly raised when a round is in the chamber. I know that this isnt possible with a rifle, but if one were to retract the bolt slightly a finger or some such could drop into the channel and "feel" the round or lack thereof, and either raise or lower a button on the exterior of the reciever, thereby indicating a round or not.

This isnt the best of ideas, but there definitely need to be somway to check the chamber without dropping the mag and feeling up thru the magwell or tring to jamb your pinky into the ejection port. If that port were slightly bigger this would be a non-issue.

I fully support 1,2,3,5,6,9 of the above reccomendations. the others can be solved by modularity and swapping components for the most part.
 

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Discussion Starter #17
Sorry about forgetting the label numbers and such....

Here's what I got (the Fastenall label on the baggie):

along the left of the bar code: 737760992
under the bar code: 25471 SSS CN 5/16-18X5/8

I'm guessing that's the part number you're wanting - it's the "cone nose" 5/16" dia 18 thread per inch 5/8" long hex set screw.

Or drop me a PM here with your addy, I'm sending these out today.
 

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Here's my 2 cents

1. Lighten this weapon. - I have no issue with the weight of the rifle at this time. It's nicely balanced, and the weight helps fight the recoil.

2. The barrel-retaining bolt had to go. - Agreed, some kind of spring loaded detent would work well here. Ideally flush with the upper handguard.

3. The sling attachment point on the rear of the receiver should change too, - I disagree here because this kind of attachmet works fine on HKs and I see no reason to remove it. Add another if you wish.

4. And speaking of sling attachment points, there’s no provision for attaching a standard 2-point sling at the rear for precision shooting. - This isn't a precision rifle so why bother, but change the stock for one with an sling mount and you're sorted.

5. I’d like to see some lightening cuts inside the upper as well - Nice idea but the XCR isn't really an FNC derivetive.

6. And just out of curiosity, why were the driving bands on the prototype bolt carrier done away with? - Nice idea but with modern lubricant possibly not so important and probably removed to reduce machineing costs.

7. If I could, I’d like to have a bolt that would be easily disassembled – without tools preferably. - Agreed, good idea. But why not just carry a second bolt to deal with issues. It beats carrying parts and trying to assemble a bolt in the field.

8. If I had my preferences on stocks, I’d opt for a fixed synthetic type, - Then buy with an AR stule tube and stick a shorty stock on it. The whole point of the XCR is they you can put pretty much whatever stock you want on.

9. Iron sights! Not that I think the XCR should come with them – The range of BUIS available is huge, again Alex not putting them on left us with the ability to customize as we please and not have to pay for a set we wouldn't use anyway.

10. And lastly, something I’m going to officially term the Jack-a-dot. - WHY?

Personally the XCR is a great platform, and apart from the damned trigger, I love it. Little developments here and there will continue to improve it over time.
 

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Discussion Starter #19
Mikey, I'll throw my comments in by number:
1. When you carry the carbine for 8+ hours a day, it gets heavy. The best carbine I've used in this regard was an ultralight AR, which came in about 6 pounds (a touch under IIRC) unloaded. The pound and a half DOES make a difference, and recoil STILL isn't an issue. When I was a youngster, I was instructing (required in OCS) and my Capt. was monitoring me to make sure I didn't give false info, answered hard questions right, etc. When I mentioned weapon weight - as a 20 year old - I said the extra weight of the weapon was negligible. As an older 'Nam vet, my Capt. informed me that I was wrong, and I'd come to see things his way later. He was right.

3. The fact is, the sling attachment at the back DOES NOT work with HK stuff. I put an HK sling off of an MP5 on the XCR, just to try it. When the oprod comes all the way back, it catches the HK snap link between the oprod rear and the sling attachment point, disallowing full travel of the oprod. Typically this only happened to me when I was trying to lock the bolt open (to show clear - administrative stuff, not shooting stuff). To clear a malf, I just ran the oprod back until it smacked the snot out of the snap link - and it cleared. If you want, I can send pics of my beat-up snap link. But I did add another point.

4. What is "precision"? I had no problems from the tower in hitting pepper poppers at 400. With a good sling, I'd wager I could have done the same from 600. With the AR15, making those shots (at 600) isn't difficult at all, but the sling helps dramatically. What I did was get my machinist to add an M16 rear sling swivel to the XCR tubular stock.

5. Take a look at an FNC. If you don't see that the operating system is virtually identical, I'll provide proof piece by piece. The only major differences are the materials of construction in the upper (aluminum tube versus formed sheet metal), the fact the gas piston isn't a single piece with the bolt carrier, the handguard / upper railed union versus the 'old style' handguards, and of course the FAL charging handle versus one directly attached to the carrier.

7. An extra bolt doesn't allow one to thoroughly clean the firing pin channel. If you're going into a very cold climate, you NEED all the extra oil out, or things get goopy, and primers don't go pop.

8. That's what I've already done - the parts are incoming.

9. That's exactly what I said.

10. Why? Get some good, proper combat coursework done, they'll explain well there. The oil holes the AR has, in that dished out area of the bolt carrier, function the same.
 

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Bravo,

PM sent.

Thanks

Juicespeare1


Sorry about forgetting the label numbers and such....

Here's what I got (the Fastenall label on the baggie):

along the left of the bar code: 737760992
under the bar code: 25471 SSS CN 5/16-18X5/8

I'm guessing that's the part number you're wanting - it's the "cone nose" 5/16" dia 18 thread per inch 5/8" long hex set screw.

Or drop me a PM here with your addy, I'm sending these out today.
 
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