@NoScoE30 If you would be so kind. hendershot175 at yah oo
You can read about my experiences with cutting and slightly reprofiling MR barrel from 16.5" to 14.5" here: Montrala: Cutting HK MR223/MR556 barrel - good, bad or ugly?
Long story short, no noticeable accuracy change and 82fps loss (2867fps to 2703fps) on Hornady Steel Match 55gr FMJ ammo that I was using at the time. I also compare there muzzle velocity with MR equipped with factory 14.5" barrel - in short, not much difference, less than 1%.