Every now and then I get a bug to make something different since Michigan loosened the rules for the shotgun zone. Last year was the 500AIMM which is a 300 RUM or any full length RUM case, cut back to 1.800 shooting a Barnes 325gr .500 bullet a good bit north of 2600fps.
This year I had the 458 bug, and following the 1.800 rules, cut back some Hornady belted basic brass to create the 458AIMM.
Built on a model 7, 22" stainless Green Mtn barrel from Jim @ Apache, Ross Schuler brake, all bedded in a 673 Guide gun stock, Zeiss Conquest 3-9 in Warne rings, 8 1/2# as you see it. Was shooting for under 8# but this thing balances about perfect as is. Plan is to Cerakote it as I'm not much into the stainless look anymore.
couple test loads:
50gr 300MP, 300gr Barnes TTSX, 2438fps
52gr 300MP, 250gr Hornady GMX, 2658fps
I about run out of case capacity for 300MP, maybe try H110 or Lilgun, although the GMX prove accurate, 2650fps from a 22” barrel not just too shabby.