January 13, 2008, 09:22 PM
I received several Pre-production UBRís for T&E and figured I would share what I found with everyone.

Concept: The UBR is innovative in that it keeps the top portion of the stock fixed and the bottom portion adjusts to different lengths. The way it is constructed gives you the strength of a fixed stock, with the adjustability of a collapsible stock. It has seven positions, including fully closed and fully extended. When closed, it is the same size as any other collapsible stock. When it is fully extended, it is about a half inch longer than an A2 stock. You have got to be a pretty big fella to need that setting, but its there if you do.
One of the best features of this stock is that you can set a preset for the setting you use most. This is great for individuals who use a setting somewhere in between fully extended and fully closed. This way you can keep it fully closed when you need the room for storage and instantly reach your desired length of pull when you need it. The preset can also be bypassed with the push of another button. This helps if you find you main setup is for armor and gear, but occasionally use the rifle when not wearing armor and need a longer length. The cheek weld is very comfortable with this stock and can be adjusted to two different widths. Weight is heavier than other collapsible or fixed stocks, but not by much. This is necessary to add strength to the adjustable system. I did not find the weight to be a burden on my 10.5Ē or 14.5Ē carbines.

Components: Construction of the UBR is a propriety polymer, molded in one of three colors. The main components are polymer. The buffer tube and notched upper are anodized aluminum. The latch appears to be steel, but Iím not certain. The female sling attachment points are also steel.
The Pre-production UBRís come with two different width tops which can be changed with the removal of four hex head screws. It utilizes an entry length buffer tube and carbine length buffer spring and buffer. The buffer and spring are not included so if you are moving from a rifle length system, you will need to order replacements. The lower portion of the stock contains a small compartment which can be utilized for storage of any number of different items. I put a boresnake in mine, since I utilize a MIAD grip for storage of a spare bolt and firing pin. The compartment will fit a spare bolt if you like, but it will not fit a firing pin. It is about 1/4Ē too small, but you might be able to open it up with a dremel tool if you really need that capability. Just be careful where you grind because you donít want to ruin your $250 stock! The lower stock includes provisions for a quick release sling point at the front and back on both sides. Unlike the Larue sockets, these allow the complete rotation of the male portion. Iím using a single point ASP sling on mine and donít mind its rotation. I also have a VTAC 2 pt sling and didnít find it made much of a difference. I prefer the single point these days anyway, but just something to be aware of. There is also a traditional sling loop built into the lower at the rear, for traditional attachment. I believe the production version will only include one side of sockets, but it seems like you could reverse the side you wanted them on with a simple change.

Oh, before I continue, one note on screws in general; USE LOCTITE! Go and get yourself a tube of blue loctite and go over your rifle. If you have screws, and they are not already loctited, get too it. Its no fun to be walking through the woods, or a town and find that your fancy $150 BUIS fell off. If your lucky youíll find the sight and probably only need the little fancy machined nut. That should take a couple weeks to get. If you have optics, just wait till your zero shifts because your mount came loose. Firing a weapon in any decent amount will loosen screws. Determine the critical ones on your rifle and use the loctite. Donít use red unless you really like whatís on there and donít need to change it. The UBR has only one that must be done and it is the screw that fixes the top portion of the stock to the entry length tube. Ok, off my soapbox.

Not too terribly hard if you are the least bit mechanically inclined. Start by clearing the weapon, then remove the upper from the lower. Remove the buffer and spring, set aside. Place the lower in a padded vise, be careful with the amount of torque you use. If your stock was a collapsible and had the castle nut staked, and it should have, you will need to get a punch and hammer and give the stakes a couple wacks to remove material. Then you can use your stock wrench to turn the nut loose. If you donít have a stock wrench and canít borrow one, I suppose a screw driver will work to loosen the nut. Loosen the tube, paying attention to the take down detent spring and the buffer retainer and retainer spring. If you donít, the retainer spring will go into orbit after a couple turns of the tube. Remove the tube and set aside. Take the entry tube and screw it into the receiver. Make sure you donít pinch the take down detent spring. When you get close to the buffer retainer, depress it into the receiver and finish screwing the tube in. Make sure it is snug. If you have the means, make sure it is torqued. Then take the upper portion of the stock and slide it onto the buffer tube. Align the male tab at the bottom with the female portion of the receiver and make sure you donít pinch the detent spring. Once it is seated, take the buffer tube scew, apply some blue loctite and screw the upper stock to the tube. Snug it up and you should be good.

Slide the lower stock onto the rail. Depress the Latch and the Remove button on the right side and slide it on. Once over the rear preset, you can just use the latch to slide it the rest of the way on. Determine where you like the stock and count how many positions out it was from closed. Slide the stock off by depressing the latch till you get to the preset, then hit the remove button and press the latch, slide the lower off. Now, take the appropriate allen wrench and remove the front allen screw and place it in one of five preset locations. Slide the lower back on and confirm this is the right one for you. Slide it off again, remove the screw, add some blue loctite and screw back in. Slide the lower back on and your ready to go. Now, that sounds pretty complicated, but in essence is simple in practice. The key is the remove/preset button. Pushed one way and use the latch and you can remove the stock. Push the other way and you bypass the preset. Pretty simple.

I installed these stocks on three lowers. The Tan UBR is on an LMT Defender lower with a 14.5Ē LMT upper. The black UBR is on a Rock River lower with LMT 10.5Ē upper. It has an H2 buffer. The green UBR is on a Stag lower with CMMG upper in 9mm and had a Rock River Heavy 9mm buffer. Yes, these are all SBRís and registered.

I checked for any sort of binding in the tube as I slowly pulled the bolt carrierís back. I did not notice any interference. Over the past couple weeks I have put 800rds through the 10.5Ē with M855 and experienced no problems. I put 700rds of 124gr Nato through the 9mm AR with no problems. Iíve only put 400rds through the 14.5Ē, but still no problems. All of these carbines have several thousand rounds through them and are known reliable weapons. I was happy they stayed that way.

The stocks felt very comfortable to shoot and sat in the shoulder very well. Cheek weld was improved over the previous CTRís I had mounted. I dumped sand into the latch mechanism and while it made the action gritty, it did not prevent the latch from working. Once home I simply removed the lower and ran it under some running water to clear out the sand. Still a little gritty, but nothing too bad. Since these are my own rifles and SBRís at that, I wasnít about to start dropping them from the roof of my house or butt- stroking dummies, but the stock is stout. The latch is robust and appears much stronger than the pin used in standard CAR stocks. While the latch does contain springs, the two fingers of the latch can not move down unless the latch is pressed to the rear, so even if you did have a spring failure the stock would still stay in position, it would just be hard to adjust.

Well, in my opinion, the UBR is ready for production now. Some minor tweaks here and there for production purposes and thatís it Is the UBR worth it? Well, that up to the end user. If you want a simple, cost effective short fixed stock, they are already out there. The Sully Stock from Defensive Edge and the Entry stock from Rock River are good short stocks ranging from $58 for the Rock River to $119 for the Sully stock. If you need an adjustable stock, with strength at least as good as a fixed stock, then the UBR deserves a hard look. Price is comparable to the SOPMOD stock that so many favor.

For Military users, other than SF, the CTR stock is probably a better alternative because it is a quick replacement for the milspec buffer tube for those opting for individual purchase. It would be difficult to get approval to mount a UBR on an M4. Iím sure soldiers would love it though. SF has a more liberal ability with their weapons, so I could see them using this stock. On the civilian side, I see this stock being purchased by contractors mostly, with strong support also coming from police departments who emphasize the use of rifles and carbines. Individuals who like high end gear and utter reliability will also love this stock. I think its another quality product from MAGPUL than incorporates lots of ideas from real shooters. If you have any questions, please let me know and Iíll see if I can answer them for you.

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January 13, 2008, 09:41 PM
Great review, i was looking to get one of those stocks when they become more readily available but was worried that the stock would be too long when closed. I like my stocks short and your pictures show that it would work with my preferences

January 15, 2008, 09:54 AM
You can also remove the rubber pad if you want to get it a little shorter. It is checkered underneath.

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