I have two of the 12th models in 30 cal and one of their 12th models in 5.56.
They are built like tanks, sound suppression is top tier and the repeatability is just that, repeatable. They 30cal models do not shift much at all.
The best sounding suppressor I have heard on a MK12 MOD1 is the OPS INC 12th model. It is crazy quiet for a semi auto.