There are two different types, though.
M27 threaded for short actions (AT, AX, ATX, AXSA)
M30 threaded for long actions (AXMC and AXSR)
The AXMC and AXSR have 3 different bolt bodies and allow you to go from 6.5cm to 300 winmag to 338 lapua just by changing the bolt, barrel, and magazine. Takes about 2 minutes.
The ASXR replaced the AXMC recently. A post-2014 AXMC shares magazines and barrels with the new AXSR, but bolt bodies are not interchangeable between the two models.