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IDK of any Trappers issued with a 16.5" bbl.
My .30-30 Trapper has it's original 16" bbl, but now wears an older (steel) Lyman peep sight. (below, with a Henry .22)
It's worked better for me than the 16"/ported & scout-scoped .44 Marlin 1894 I used previously (uppermost rifle, below)
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