Is the reasoning behind removing some shot when using the polywad spreader to make the load fit and ensure a good crimp, or to avoid an increase in pressure? I am using a 7/8 ounce recipe that is less than 5000 psi, and the insert fits without removing shot- would this load be OK pressure wise?

Randy if your load fits and crimps are good don't worry about removing any shot. There will be no appreciable effect on chamber pressure.

Thank you, the original load had a slight dish to it, so adding the spreader made the crimps prettier.

Loading spreaders I put a Polywad on top of my normal 7/8 oz load, lightest one published by Alliant. 16.5 Red Dot no changes to anything. It works fine.

Boats

That is the recipe I use, also. I do put 1/8 oz shot on top of the spreader.