I can provide two examples.

I have a refurbished 1911 A. H. Fox "A" grade 12 gauge that is choked IC & LM (29" slightly cut barrel) that I have fired with several hundred rounds of factory steel #3's, #4's and #6s, -- both 1 oz. and 1-1/8 oz. Zero damage of any kind.

I also have a 1951 Browning A-5 with 12 gauge factory Cylinder Bore barrel that has fired over two hundred rounds of the same factory steel shells with zero damage.

Neither of these guns have any scratches or scoring in the bores.

Steel is required for upland birds at some Illinois public hunting areas.

JERRY