The first X-Bolt 6.5 Creedmoor I put in a McMillan I tested before and after. Using the same lot Norma 143gr Golden Target match ammo. Groups were shot 2rds, wait until barrel was cool back to ambient temperature, fire two more, wait and then two more until I had the 10rd group. I was able to shoot off of the porch while doing other things around the farm. With the factory plastic stock, the rifle was a 3/4 MOA at best rifle, usually averaged 1 MOA with a HVHA trigger spring adjusted to 2lbs and the Norma ammo. I rebedded the factory stock using MarineTex, rifle was giving me the same group sizes with the exception, groups went from a vertical string to a circle. When the McMillan I ordered arrived, I replaced the factory plastic stock, torqued first to 35in lbs per Browning and repeated the test using the same lot and procedure as before. Groups were in a nice little 3/4" cluster but printed about 2" high and right of the original POA/POI. Picatinny rail was permanently bedded to the action. I removed the scope, removed the screws from the 0 MOA picatinny rail and the rail fell off the action with a layer of Cerakote attached to the rail. I took the rail to work and used a dry ice blaster to clean the epoxy and Cerakote off the rail. Not happy with the 0 MOA, I ordered a 20 MOA Murphy Precision rail. I purchased and used a handheld Harbor Freight sand blast pot to glass bead the action (plastic plugs or set screws to plug the screw holes are a must) and the new picatinny rail and then mounted the rail using MarineTex. I verified, adjusted zero and repeated the first test with the factory stock, no improvement in group sizes. I then swapped to the new McMillan, first torqued to the Browning spec of 35in lbs, groups were now within the 1" orange dot and about 3/4" diameter. I decided to clean the rifle, repeat the test. After fouling the bore, groups shrank back to the 3/4" size. I waited and repeated the test the following afternoon and the groups were the same and in the same location. I noted as other's here had discussed, the shot 2 groups stayed within the cone but they moved slightly within that cone. I tried torque at 45in lbs and the overall group sizes shrank slight, maybe to 5/8" but I was still seeing movement of the two rounds within the cone, by the time you got to 10rds, you couldn't see the movement, it was within the first three 2 shot groups. I decided to clean the stock, painted version with flecks, and bed the action. I used a wooden dowel wrapped with sand paper to remove the paint,. I could see the paint was not uniform and the flecks were even thicker than the paint alone. At this point, I removed all of the paint in the action, used a Dremel with a carbide rotary file and diamond bits to open up the recoil lug and remove the paint from the bottom metal area. I made extra long action bedding screws for the process because I wanted to bed the bottom metal at the same time, the front screw is shallow and is right up to the barrel tenon, be careful there. The Browning X-Bolt uses the same 1/4-28 screws as Remington does. I removed the trigger and side bolt release and plugged everything with clay that I didn't want filled with epoxy. I bedded the entire action with MarineTex and the areas around the action screws in the bottom metal. Once everything was cured and cleaned up, I repeated the test. The group sizes at 35in lbs were not discernable from 45in lbs. They were however now 5/8" and showed no signs of wandering within that cone. The best 5 shot group to date from that rifle was with the Berger 144gr LRHT at .487", but the majority are in the 5/8" range and this is probably because I am the limiting factor.
I said all that so you can understand, if you buy one with the molded in finishes, you can probably swap and see a drastic improvement over the plastic factory stock, if you buy a painted one, it's a crap shoot. You will see improvement, but you may be leaving something on the table if you decide not to bed it or have it bedded.
Also, the factory Pro stocks are just a few ounces, less than three ounces lighter than these new McMillan stocks, 28oz versus 30/31oz of the McMillan. I have a new Carbon Sonoran Ambush on the way for a new 280 Ackley X-Bolt and I have 2 short action Carbon Sonoran Ambush stocks in the box besides the 3 I have already bought.
If you buy the Pro stock, you will have to remove the factory bedding and rebed your action in the stock.
They are one of the simplest and easiest upgrades for a factory Browning X-Bolt. Plus, if there is ever a problem with the stock, McMillan will take care of you where Browning will not.
