This will be a somewhat lengthy post, so TIA for your time. Here's my problem - I recently bought a new MSR in .224 Valkyrie. Before breaking it in, I stripped it down, thoroughly cleaned the barrel and BCG, lubricated the action, and mounted a Vortex Razor HD in a Badger unimount. I broke it in by firing one round and cleaning the barrel for the first five rounds. Then I fired two rounds and cleaned the barrel for an additional ten rounds. then I fired five rounds and cleaned the barrel until I finished off a 50 round box of AE 75 gr. This method has always served me well with my three Savage bolt guns. During the break-in, I got a rough 100 yard zero on the scope. I then began firing the 90 gr SMK and around the 100 round mark, I was getting nice 1/2" groups from the bench shooting off a bipod and rear bag. Around the 200 round mark, I noticed the groups starting to open up significantly with both the 75 gr AE and 90 gr SMK. Total round count as of this posting is about 400. I don't expect great consistency from the 75 gr, but it was holding about 1.25" or so when everything was going well. This weekend the rifle struggled to shoot anything under two inches with either ammo while being shot the same way that had previously gotten me the 1/2" group. I started troubleshooting by removing the hand guard and checking the barrel nut for correct torque. It didn't budge when the wrench hit the 35 ft lb mark, so I left it alone. I checked the brake and all seemed well there, too. I disassembled the BCG and made sure everything was clean and tight there. In the interest of being thorough, I also swapped optics and confirmed that with a completely different setup that the problem was still present. Just for peace of mind, I installed the Razor from the MSR onto my 6.5 CM and immediately shot a 3/8" group, so I'm 100% certain it's not an optic issue. During the troubleshooting process, I thoroughly cleaned the barrel on two different occasions with Butch's Bore shine to insure there was no fouling present that would effect accuracy. Clean or fouled makes no real difference. Visual inspection of the bore revealed nothing to the naked eye, but I can't get a good view of the throat. I haven't made any gas system adjustments because it's ejecting about 4 o'clock and has never had any feeding or extracting issues. The only upgrades to the rifle are an ambi charging handle, a PRS gen 3, and Atlas bipod. I want to cover as many bases as I can before sending the rifle back to Savage and any input you have is greatly appreciated.