Building a trapdoor sporting rifle

[1871Trapdoor]

Gentlemen, am new to this forum and am in need of help. My brother bought a sporterized trapdoor in .45-70. However, the breach block is stamped “Model 1872”. I can’t find any reference to a Model 1872 trapdoor. And before anyone asks, yes, the last digit is a 2, not a 3. Can anyone shed some light? Thanks.

[Tony Beck]

Can you post a photo of it?

[Dick Hosmer]

Definitely need to see a good photo of that marking. It is VERY uncommon, but Bubba-stamped blocks have been seen. That said, the all-time puzzle (never verified or clarified) has to be the mysterious "1871" dated lock plate. The late Bob Hill, an experts's expert, tried mightily to purchase the arm from the family who had it - and Bob didn't buy fakes. Astute older members may recall that he MADE a few, but that would be another story for another time...