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The UBR and you (as an XCR owner)

6946 Views 10 Replies 8 Participants Last post by  Sean K.
OK, hinge showed up this afternoon (thanks, Terra!). Got the UBR on the rifle. Pictures will be coming soon (I hope, if the camera cooperates), but if you've seen the pics on arf.com, you'll have seen this (except for the KAC sights my gun has).

First impressions:

It goes on pretty easily, but there's a fly in the ointment right off the bat. This stock is designed for AR15s. It shows in several ways. You're going to see this AR comment a lot.

Firstly, there is what almost looks like a retaining bolt (it's not, not sure what it is) that interferes with the stock going all the way down the spring tube against the M4 adaptor block. It's a cosmetic thing, but it shows you right off the bat this is an AR stock.

Secondly, the additional LOP is a real issue. I like a short stock like most people. The stock is only usable if you collapse the thing fully, or maybe one position out. Like has been pointed out before, if you have arms like an ape you might like this. However,for more normal folks the M4 block brings unwanted additional LOP. Seriously, I don't think you want a folding hinge on this stock on the XCR.

Next up is the width of the stock. It's comfortable, and has a very stable cheek weld. The problem is it sits low in relation to AR height iron sights or optical mounts. My Larue mounts sit too high. This wasn't too noticeable with the FAL stock, but with this one it really comes home. My advice from here on out is to get low Larue mounts. Mine may very well need to be changed.

Lastly, it's heavy. It actually balances my heavy barrel XCR rather well, but it is a touch too heavy for the normal tension of the hinge. Two thoughts here: one is to ditch the hinge and just fix the stock. The other is the XCR needs a locking detent in the folded position like a real FAL. Considering some of the other issues, I'd just ditch the hinge if you really must have a UBR.

Bottom line: it's an AR15 stock and it shows. It's a slick item, but not really well suited for the XCR. Those of you looking for something better than the FAL-style stock probably should wait for whatever Alex is cooking up. I've spent some time looking at this combo and can't help but come to the conclusion it'd be better off with a fishtail style stock like the SCAR. The whole rear stock mount would have to be changed, but I think it'd be the better setup.
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Thanks for the rundown, I am looking forward to what Alex has up his sleeve
Thank's Sloan, you just saved me a bunch of bucks. I'll just wait for what Alex has behind door #1.
I too can't wait to see what RA has in store. I like a folder but not the CTR as a folder. I have been running the CTR fixed for some time as I like some LOP adjustment, especially when wearing entry armor.

The M4 folding adaptor takes up too much room for me. If the FAL folder would just adjust in and out a couple of spots, it would be perfect. I really like the thinner profile as compared to the M4 stocks.
I'm actually quite pleased with how comfortable the standard XCR folder is. I've shot with other skeleton stocks on AKs in particular, and just didn't care for them for some reason. I didn't really want an AR stock on my XCR though, so I just figured I would go with the cheapest option (the folder) and hope for a quick arrival of the SCAR spec stock.

Well... the XCR skeleton stock, between the padding on the top bar, and the nice butt pad, is more comfortable than I anticipated. The LOP is perfect. I will probably get the SCAR stock when it comes out, depending on the functionality offered, but for now I'm happy with what I've got.

I have the Troy folders on my XCR now. When I shoulder the rifle, they are a tad higher than normal irons that I am used to, but nothing that makes it unuseable. It is a cheek weld that I am normally used to acquiring with a red dot. A red dot mount that would put the irons in the lower 1/3 (standard AR height) would put the Aimpoint to high. Therefore, I'm just going to go with the low mount, which should position the Aimpoint perfectly, and keep the irons folded when not in use.
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I've gotten more time to fool around with the UBR/XCR combo today.

I think one thing I'm running into is that the XCR really doesn't interface all that well with AR15 accessories. Things designed for the AR boreline just don't line up quite right with the XCR. It's not far off, but there is a difference. I think low mount bases are a must right now. I have Larue high mounts presently installed (typical AR15 height). They're just a touch too high. Same with the KAC irons. This isn't a huge deal, but it's noticeable. With the FAL folder you don't really have a cheek weld like you do with more substantial stocks. I know I index the stock from the flat bone just behind the chin. This gives you a headsup position that lines up fairly well with the AR15 stuff.

Queue up the UBR. The UBR has a very substantial flat where your cheekweld will be. It's very comfortable, but promotes a lowered head in relation to the sights. You can adjust your cheekweld so everything lines up OK, but it really could use about 3/8" more height. The cheekpiece of the UBR is removable and replaceable with different heights, widths, etc. However, Magpul isn't even making the stocks for commercial sales just yet, much less replacement cheekpieces. Advice is to get as low as you can go for mounts on the XCR. Anyone thinking about going Larue, I'd recomend the 1.4" mounts (think that's what they are; it's on the site).

Then there's LOP. There's no way around having an excessive LOP with the folding M4 block. I'm not sure exactly what I'm going to do with mine at this point. I suppose I'll leave it as it presently is for a few weeks and see how it grows (or not) on me. I'm thinking about getting a fixed M4 block, however. The protrusion that doesn't allow the stock to fully collapse (about 1/8" gap) is an index detent that normally would be inside the AR15s reciever. On the XCR it just butts up against the block. This could be ground off, but I'm not sure I'll keep the stock at this point so I'm not too inclined to go hacking on it just yet.

If Alex does bring out a SCAR-style fishtail stock for the XCR, I'll be first in line with cash. The UBR is OK, but it's not THE stock for the XCR. We don't have that stock yet. I think the gun does need a stock that brings the cheekpiece all the way to the top of the reciever because of the heights of existing mounting hardware. A fishtail style stock with the hinge flush against the reciever would solve the height issues, I'm thinking. Also, we wouldn't have to put up with a buffer tube we don't need.
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*patiently waiting on pictures*....
Happy New Year......... where are the Fotos ??? ::) :eek:
I'd also like to see these pics as well as find out what the OP ended up deciding about the LOP, folding M4 stock adapter and cheek riser issues.

For instance, anyone know if the CTR cheek risers will work with the UBR?

Sean
I've gotten more time to fool around with the UBR/XCR combo today.

I think one thing I'm running into is that the XCR really doesn't interface all that well with AR15 accessories. Things designed for the AR boreline just don't line up quite right with the XCR. It's not far off, but there is a difference. I think low mount bases are a must right now. I have Larue high mounts presently installed (typical AR15 height). They're just a touch too high. Same with the KAC irons. This isn't a huge deal, but it's noticeable. With the FAL folder you don't really have a cheek weld like you do with more substantial stocks. I know I index the stock from the flat bone just behind the chin. This gives you a headsup position that lines up fairly well with the AR15 stuff.

Queue up the UBR. The UBR has a very substantial flat where your cheekweld will be. It's very comfortable, but promotes a lowered head in relation to the sights. You can adjust your cheekweld so everything lines up OK, but it really could use about 3/8" more height. The cheekpiece of the UBR is removable and replaceable with different heights, widths, etc. However, Magpul isn't even making the stocks for commercial sales just yet, much less replacement cheekpieces. Advice is to get as low as you can go for mounts on the XCR. Anyone thinking about going Larue, I'd recomend the 1.4" mounts (think that's what they are; it's on the site).

Then there's LOP. There's no way around having an excessive LOP with the folding M4 block. I'm not sure exactly what I'm going to do with mine at this point. I suppose I'll leave it as it presently is for a few weeks and see how it grows (or not) on me. I'm thinking about getting a fixed M4 block, however. The protrusion that doesn't allow the stock to fully collapse (about 1/8" gap) is an index detent that normally would be inside the AR15s reciever. On the XCR it just butts up against the block. This could be ground off, but I'm not sure I'll keep the stock at this point so I'm not too inclined to go hacking on it just yet.

If Alex does bring out a SCAR-style fishtail stock for the XCR, I'll be first in line with cash. The UBR is OK, but it's not THE stock for the XCR. We don't have that stock yet. I think the gun does need a stock that brings the cheekpiece all the way to the top of the reciever because of the heights of existing mounting hardware. A fishtail style stock with the hinge flush against the reciever would solve the height issues, I'm thinking. Also, we wouldn't have to put up with a buffer tube we don't need.
If your not happy with it...dump it now on gunbroker or e-bay while they are bringing top dollar. Some guy is selling them for $370 right now on ebay and getting it.
I see people on Ebay selling it for that....but why do you think they are actually getting it? I just attributed it to people figuring out that with the 30% Live.com promotions, they were selling them at a $20 discount off MSRP at around $350.

Just wondering.

Sean
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