Home Forums Reloading Big Game Rifles Diagnosis Please

I'm not a big fan of such small changes in charge or seating depth.

With many powders, a 30 degree F change in barrel temperature is equivalent to a grain of powder. If you're not controlling barrel temperature to within a degree or two, small changes in charge or seating depth will be completely swamped by the temperature change. If you can get it to work today, chances are it won't work tomorrow.

If it were mine, I'd start by re-checking bedding. After a little coaching from someone who understands better than I do, I found I could feel barrel rubs that I couldn't feel before. In some cases, I can feel the barrel rub "grab" on the ink on a dollar bill, and smoothly slide over unprinted areas.

If that is unproductive, I would remove the scope and bases.

Once in a great while, the front screw on the bases will bottom out on the threads of the barrel before the screw is tight. That's a hard one to detect. Remount the bases, put blue LockTite on the screws, and torque them all to spec. Insure that the rings are aligned so that they do not stress your scope when it is mounted.

Torque your action mounting screws to spec. Once you do, loosen the rear screw and see if the rear tang moves up out of the stock. If it does, you have a bedding problem.

Start your shooting test with a different scope.

For a short test, torque the ring screws to spec and see how the rifle is shooting.

Then switch back to the scope you're using. Put blue LockTite on the ring screws, and tighten them only to spec, so that the scope is not stressed.

Do not zoom the scope while performing these tests. You may have a situation where the scope does not hold zero while zooming.

Once you can get the rifle to shoot itty bitty groups without zooming, check to see if your scope returns to zero after zooming.

If none of that helps, then a good guess is that the barrel-receiver junction is not as rigid as it should be. Charlie Sisk knows how to fix that.

Oh, and one more thing: If you are using aluminum rings and a rail type mount, be sure that you didn't over-torque the screws that attach the base to the rail. A little bit too much torque, and the heads of the screws pull through. You can knock them back out and re-seat them with JB Weld.