Within the previous project activity, the upper and lower receivers were assembled, there was a large hole at the back of the assembly, a very nice Magpul adjustable stock sitting on the bench and everything was missing that was required to connect the two. There was also no optimal ammo to make it all go “Boom!”. So I did what every firearm enthusiast does at such moments, I broke out the credit card and bought more parts and some more tools. Let’s face it, buying more parts and more tools is half the fun of owning firearms and its only one percent of the cost of building say… an eight second quarter mile big block 1993 Mustang. The very same one I promised my wife I would stop incessantly talking about.
Magpul’s Generation II Precision Rifle Stock…
Everything about this gun is long range and consistently hitting long range means the ability to tweak and adjust and to settle in, human and firearm well connected, contact points well supported. To that end, a Brownells # 100-002-947 black Magpul AR-Style .308 Precision Rifle Stock was selected. The retail price is about $255. Buttoned down it is very compact and very solid, but it can easily, and positively, be adjusted for comb height and pull length as pictured above. Sling mounts can be swapped to opposite sides and opening a cover at the bottom exposes a rail used to mount a monopod. The Magpul unit mounts to the LR-308 with an AR-15 A1 extension tube.
Brownells Stock Completion Kits
The LR-308 was built up from a stripped lower and complete upper, consequently, the components required to mount the stock needed to be acquired separately. The easiest way to secure these parts to purchase a Brownells A1 Stock Completion Kit for $39, Brownells # 080-000-553. Pictured above, bottom to top order: buffer body, extension tube, buffer spring, and Superior Shooting’s chrome silicon flat wire SR-25/AR-10 buffer spring. The Brownell’s kit includes an AR-15 buffer spring that was needed for another project, so the Superior Shooting piece was ordered as a substitute better suited for the LR-308 gun. If the AR-15 spring were not required elsewhere, parts could have been purchase individually as required. The AR-10 Superior Shooting spring is priced at $30.
Stock installation…
Stock installation is relatively straight forward. The upper is removed. The buffer retainer and spring are dropped into the well inside the aft receiver ring, then the butt stock extension tube is screwed into the receiver. The buffer retainer needs to be depressed as the threads from the extension tube near the buffer retainer’s body, then the extension tube is screwed in the rest of the way as pictured below.
Because the extension tube and receiver are made of aluminum, a couple of drops of oil on the threads will assure the parts can be separated at a later time. With the extension tube screwed in place and hand tightened, an armorer’s wrench is used to grip the flats at the back of the tube and a torque wrench inserted into a driver cutout in the armorer’s wrench us used to tighten the tube to 35 ft/lbs. I put the lower receiver in a bench vise using an AR-Style .308 Lower Receiver Block, Brownells # 080-000-494, which made the process easy. The receiver block cost about $45. While not essential, it was a good investment for future AR-10 type projects. The torque wrench pictured above was purchase when I was assembling a 428 Super Cobra Jet engine in 1972 and needed something more accurate than the pointer torque wrench I purchased in 1962. Maintained, tools will provide a lifetime of use.
The buffer spring and buffer, pictured above, are fed into the extension tube Slinky style with the buffer retainer depressed when it is time to clear the end of the buffer. The hammer may have to be cocked to provide clearance for the buffer body. Once together, the buffer should move in and out within the extension tube freely and the buffer retainer should move freely within its well in the bottom of the receiver ring.
Beginning top left, then clockwise – the two butt plate screws are removed and the rubber butt plate is pulled. The stock is slipped over the stock extension tube. If the fit is too tight, the screws on the sling mount, footman’s loop, are loosened, then the stock is slipped fully into place. The vented screw supplied with the stock is installed and screw driver tightened. The screw is easy to identify; blue thread locker and a hole drilled lengthwise through the screw shaft and head. The rubber butt plate is reinstalled and the lower receiver can be reassembled to the upper. The result should be a working gun.
If it’s good enough for my Swift…
This LR-308, with a 24″ barrel, is a big ol’ long distance shooter and I tried to keep this in mind when I went looking for optics. I also tried to keep in mind I really like the looks of this gun so I needed something that really… fit. Based on the very positive experience I had with my Model 700 220 Swift and a Bushnell Elite 6500 4.5-30 x 50mm scope, I decided I’d mount the same optics on the LR-308 and prep it for some ammo evaluation.
The scope itself is actually compact in length and relatively light for a scope of this magnification, however, due to a newer generation of optical mounting design, a large 30mm tube and excellent lens coating, images are sharp and bright with perfect contrast. In use the Elite is more like looking through the lens of a Nikon camera than a typical rifle scope. Very nice. Combined with the mount system described below, the optics weigh 2 lbs even. The rifle came in at 12 lbs 13 oz with magazine in place for a… stabilizing 14 lbs 13 oz total with scope.
American Defense’s AD-RECON-S Scope Mount
There isn’t much point in assembling a gun with long range potential unless it receives appropriate optics and a mount system that will hold up under the battering of lots of rounds fired. To that end, an American Defense quick detachable mount system was installed. Brownells # 100-003-654 is designated for the 30mm scope tube mount. I believe retail is approximately $170. Cross bars, camming hardware and fasteners are steel, the mount body, rings and release levers are hard anodized aluminum. The finish is matte…ish.
There is a lot of clamping surface, and the cross bars and ring dowel pins assure everything will stay put on the gun and at the rings. And yes, they have a good look and they do cut down on weight. I know, aluminum mounts with a pound and one half scope on a twelve pound rifle may seem like ordering a Carl Junior’s Western Double Cheeseburger with a large order of fries and diet Coke, but it actually makes sense. A light mount reduces the amount of kinetic energy transferred to optics under recoil and helps cut down on failure of expensive glass.
The mounts are a snap to install. The locking levers are adjustable for tension. American Defense recommends ring hardware is torqued to 20 – 25 in/lbs and they package thread locker, the removable type, with the set. The scope plopped in cleanly, no tube scratching and laser sighted neutral in windage and in the top third of elevation adjustment.
And when the dust settled…
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The LR-308 is quite a piece of machinery. It is a really solid gun, very soft recoiling and exceptionally consistent in shot to shot placement. A .308 Winchester gun can be built with lighter weight parts selected that brings the total weight down to 7 lbs and change.
Using assembly guides and packaged related parts sets from Brownells took the stress out of the process and assured selection of compatible parts. Always nice when a gun comes together and works reliably with first check out.
As a sub MOA performer the gun is bolt action accurate, something common place with AR type guns, and it is probably easier to shoot than most. Superformance Hornady 150 grain ammo was able to deliver 3,000 fps plus all day long and the gun digested anything fed to it, including handloads, without complaint. The only obvious work remaining for me is a trigger job to get the pull down into the four pound range, although the one that came out of the small parts kit is clean. I’d also like to add a bipod. Yup, I can see surprised coyotes at 300 yards in the near future.
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