I used to shoot 1/2 to 1 1/2 inch groups with my no.1b. No modifications at all, just handloads. I sold it and now have the no 1 varmiter in the stainless laminate. Haven't had a lot of time to play with it yet but the first load I tried was 1 and 1/2 inch group off the box of a pickup. I will get to the range one day for some real fun. I believe the mod is a simple rubber o ring acting as a washer on the forearm. This should "float" the barrel a little.