I bought the full set in gunsmithing school. They work fine on regular everyday American guns with wide slots. I bought the thin bit insert set and they have been quick to break or bend. I keep forgetting to ask but I think Brownell's will replace the damaged ones as long as you do not grind on them. Truth be told......I like old Stanley screw drivers I can buy for 1$ at pawn shops. Excellent steel that hold up well. Grind to fit as you need.

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