I am putting together an XP that I'd like to try shoot cast bullets through. It has a new Shilen stainless 1:9" twist and I have not slugged it.
I used to have a TC barrel in .256 WM that shot .257" bullets great.
I'd like to ask if most of you shoot bullets sized to .257" or to .258".
Slugging the barrel is not as beneficial as a chamber cast would be. I whould size the bullets to fit the chamber throat (free bore - leade). Then seat the bullets as far into the throat as possible. I have a 7 TCU XP100 with a .284" bore. I could not get acceptable accuracy until I sized to fit the generous throat, .287". I use this same technique on two other 7mm guns and each of these 3 require different bullet dimensions. They each perform their best with bullets that fit the throat.
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