The thing that I like the most about the XLR Industries Evolution Chassis System is that it uses Accuracy International magazines, which are some of the best magazines you can find. The only variation to this is that the CheyTac actions use M310 magazines. And for the final finish the Evolution Chassis comes anodized in your choice of redstone, black or green.
Showing the rib cut out to accept the ultra mag case.
As a side note, some shooters have been modifying the Magpul PRS stock, but permanent alterations will have to be made to the stock and will make the stock unusable for use on the AR type rifles.
Now it was time for me to make a decision on what to go with. I knew I was going to build a 338 edge in a tactical style rifle, but most of the ones I see are single shot due to the OAL of the cartridge, and I wanted a repeater. So I looked around and found a Savage 7mm ultra mag, and a week or so later it was headed to the gunsmith for a new barrel and brake. Then I called Kyle at XLR and started brainstorming on a chassis. With the XLR chassis that used Accuracy International magazines my only option was the CIP mag, as it has an OAL of 3.725Ē. After a little help from the guys at Savage Shooters, we took some measurements and called XLR. We decided that the mag well was large enough to feed the larger cartridge without any modifications to the action, so I ordered the XLR Evolution stock with the tactical butt stock.
After a modest 8 week wait my chassis was sitting on my door step. When I opened the well wrapped package I was taken away by its quality and rigidity. There were no machining marks, scratches or poorly fitted parts, just a high quality piece of art. I couldnít wait any longer so I headed to the basement and started bolting up parts. I used the supplied action screws, and the action bolted right up with no off center screw holes. I torqued the action screws to specs and tried to install the hand guard. In my haste I didnít read the directions so I had to unscrew the hand guard clamp to allow the alignment hole on the fore arm to slide over the dowel on the chassis. I unscrewed the clamp and started over, following the instructions.
Once I had everything bolted up, I started to adjust the stock to fit. I was very impressed with the amount of adjustment this system has. The cheek piece has more than enough adjustment for my extra high rings and is very comfortable to use. The length of pull also has plenty of adjustment. This particular butt stock does not come with a cant feature, but the recoil pad does adjust up and down. One downside to this stock is that you have to remove the adjustable cheek rest during cleaning if you have a long action. I believe that a short action bolt will come out without removing it, but I donít have one in front of me to say for certain.
Once everything was in place I decided to do a function test to check for proper feeding. I loaded up 5 dummy rounds with empty cases - 250 grain Sierra Match Kings and no primers. My OAL was 3.685, which left plenty of room in the magazine. I loaded the first round in the magazine, but the problem was in trying to load the second.
I learned that the Accuracy International 338 Lapua Cip Mags werenít designed for the Ultra Mag cases due to the placement of the shoulder on the case. It sits farther forward than the Lapua, causing the case to catch on the front rib on the mag. So with a little cutting with my cut off wheel and a file I removed the rib on both sides to allow the cases to go properly in the magazine. With this little hiccup out of the way I loaded the magazine and cycled the bolt. All of the rounds cycled like they were supposed to with no jams. I repeated this several times and had the same results each time. Now donít forget that this was my 250 grain Match King load that I was using, which fell under the 3.725Ē OAL limit.