Worked very well for me on my Stevens 25-06, made nice groups into touching groups. You have to experiment where on your barrel it will be most effective, for me it was inch past the muzzel, looks silly on the end of your barrel, I cared not as the accuacy improvement was good.
My bud has a Sav 22-250 pre Accu. and it wasn't grouping very well, although it could have been the Win Supreme ammo, slid that baby on and his groups became substancially tighter. Oh ya they have a new model out now for HB rifles. FS