[I wouldn't consider refinishing a stock without finish sanding it first with 400 and 600 grit to smooth the surface. That would be like repainting a car without any sanding or surface work. Proper preparation of the wood surface significantly improves appearance of the stock after application of new finish ]
While that's de rigour with new wood, or wood that's been repaired (holes & cracks filled/dents raised/whatever), it's about 10 years out-of-date for refinishing existing wood stocks, not needing repair, and having a non-epoxy/poly finish.
In the 10 years since I stopped sanding and started using stripper ILO sanding/etc, I've redone over 50 stocks for customers with zero issues or problems.
DON - You might want to do a quick check under the buttplate, before any strip or refinish job on a poly/epoxy finished factory stock - as on some, the "woodgrain" is an application (first instituted by Miroku, and now Beretta & others), and not the real wood.
If the wood inside the inletting, or under the BP, is plain/light and/or very different-looking from the finished surfaces, what you're looking at there is what you'll get everywhere after the "finish" is removed on those particular stocks.
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