John: Jon could give much better advice if you could share where, exactly, is the barrel MWT .018", and if the barrels are fluid steel or pattern welded.

Every vintage Bulk or "Progressive Burning" smokeless pressure-distance curve shows the pressure to be less than 1500 psi at 20"; modern Dense less than 1000 psi.

This is 12g 1 1/8 oz at 1200 fps from the Alliant site


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