Wow, I finally found a bunch of guys as crazy as I am! Here's a few photos of my 45-100 built on a 1970's Merkel 12 ga. Used Ellis Brown's book for info. Still trying to get the shots closer than 3" apart at 50 yds. Found that the muzzle block needs .008" taken out to get regulated. Before I soldered and blued it, the shote were crossing, so the 2 setscrews were to spread the left barrel to regulate. Can't get above 2250 fps with a 350 gr bullet without the cases stretching .006" per firing, which means the action springs tis amount(egad!). Maybe the greener bolt is not tight fitted?