Yes, as long as your barrel matches the thread, it will work without issue.
No, no crush washer is needed.
As long as it's a 5/8-24 thread, then our 5/8-24 Elite Brake will work without issue.
As long as your rifle is threaded 5/8-24 or larger, then it will work without issue.
It installs via the barrel threads. If your barrel isn't threaded, then yes, you would need to get it threaded to be able to install the brake.
Yes, the MDT Elite Muzzle Brake model MPN:103516-BLK will be compatible with your Savage Axis 2 in .308.
Yes, the MDT Elite Muzzle Brake model MPN:103516-BLK will be compatible with the Aero Precision M5.
If you have a 2015 or newer PTR-91 with 5/8x24 threads, you will be able to use model MPN:103516-BLK. 2014 and older models use a 15x1 thread pitch.
Yes, both 6.5 Creedmoor and 6.5 PRC have the same bullet diameter (0.264"). Meaning that as long as your rifle has the same thread pitch, the MDT Elite Muzzle Brake will fit and function as intended.
Yes, the MDT Elite Muzzle Brake will work with a MVP LC in 6.5 Creedmoor. You will need to determine the thread pattern of your barrel to decide which model you need. You will need either model number 103516-BLK or model number 103663-BLK depending on the threads of your barrel.