Last week I decided to do a seating depth comparison during one of our 1000 yard practice sessions. I had started experimenting with Berger 155 hybrid bullets in my Palma rifle a few months ago. They seemed to shoot with about the same accuracy as the Berger 155.5 grain fullbores I have been using successfully, but are aerodynamic enough to print about 1.5 MOA higher at 1000 yards. My initial seating depth was an educated guess based on conversations at our practices, and they shot well. Now that our State Championship match has passed, decided to experiment, and loaded up a few 0.015" deeper for grins.

Below is a 10 shot string at the original seating depth. I had just shot a string with the fullbores, and you can see the first sighter printed high. Once I had the group centered I did not touch the elevation dial on the rear sight for shots 1-10.

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I followed this group up with those seated 0.015" deeper. The wind angle had changed and required a shift to center the group. Again the elevation was not adjusted once the record shots started.

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I was surprised to see the much tighter cluster shown (the grid is 1 MOA) and will try to verify the results in additional side by side comparisons. Both groups had a single bad flyer, a 9 for one and an 8 for the other. Unfortunately I have to say they were both on call and I won't hold them against the load results.

Shooting with a sling and irons, I have found this sort of comparison a decent way to dial in loads and also get in match practice. The F class guys we shoot with do run the pure ladder type tests with their much more stable set ups.

Happy New Years!

Last edited by MikeS; 01/01/23.
Too close for irons, switching to scope...