WB
Kase was a wealth of info on the Grizzly Win Mag for me
Tuesday, May 29, 2018, 06:41

I installed #18 lb. Govt. springs for the Recoil ass. and fitted a Commander bushing on the barrel. The Millett rear sights have a engineering flaw. Underneath is a very tiny E-clip that can come loose. Usually it's still held captive so get a light colored cloth on the workbench to be safe. When you remove it it WILL FALL OUT. If the clip comes loose the rear blade will hunt around only a few thousandths but plenty to throw your groups all over.

I bet a dollar to a doughnut that is the issue you are having. The guns in general are about like an accurized Govt. model and usually can do 3" groups at 50 yds pretty easy if you are up to it. Certainly at 25 yds.

FWIW...