Hello,
I have a question I hope someone can answer. I bought an old topper 12 gauge shotgun with the case hardened frame and found a 20 gauge USH barrel on here for it. It is only going to take some minimal fitting which I don't believe will be too much problem with the detailed guide you all have put together. This old frame has the low style hammer with a transfer bar. What is your experience with low hammers and hammer extensions. It doesn't look like the extension will clear the open lever. It will wear a 1.75-4x32 bushnell banner shotgun scope on xtra high weaver rings.
Thanks,
Matt
P.S. I would just try to fit an extension but the gun is not in my possession.