HI Itt and All, I have a couple 1874 Sharps. So I have direct example's of what might interist anyone that wants to build one as far as dimentions go. I have 1 original made in December 1876- shipped 14 January 1877 to the "B Kitterich and Company, Cincinnati Ohio" They were sold by the pound and then what you had them equipped with. This one is: 13-1/2 pound with barrel ladder sights, 30" 1-1/8 octagon barrel, 40cal 2-1/4 Sharps bottle neck rechambered to 2-7/8 straight. Also called 40-85 Sharps straight. It is NRA antique 80% It is in perfect shootable condition. The other one is a UBERTI 45/70 or 45-2.1 with 30" 1/2 octagon 1/2 round barrel. It is made by Pedersoli for Uberti. Now here is where you WILL run into problems getting dementions off of examples. Every make is different but 2. The only one that is true to the original is the one made by SHILOH. And from the Montana factory only. The ones they made on the east coast are completely different. That was one of the reasons they split off from C.Sharps and moved to Montana. I have this information from Kirk & Lucinda at Shiloh. There rifles are the only ones true to the originals. You need parts for a original there's fit. The Pedersoli/ Uberti seem to be the closest but every dimention from receiver to fireing pin is just a little different. Armi-sports are even farther off. The original east coast early C,Sharps/Shiloh that I compared to my original were even farther off, not even main receiver size was the same. So your print's need to have all there parts from 1 rifle from 1 company. Shiloh built there first rifle in Montana piece for piece from an original like mine so every dimention is the same. From what I understand there 1st east coast rifle from the early 70s was built from pictures with no dimentions. And they did a very good job doing it. We have to thank them for starting to bring these great rifles back. I hope this helps with the reason for parts not fitting. Your print's just might be drawn from a pile of miss matched parts from the different manufactures. As far as how strong the 1874 action is, all current ones are SAMMI spec. In 45/70 with a case diameter of .504 at 28,000psi. Factory 45/70 load pressure. If I can help with measurements I will do what I can but you have to understand I will not take the original apart as it is priceless. A past owner polished on it, and because of that I ended up getting it from him when he realised what he had done. And everyone tried to steel it from him to make a buck. I consider myself as custodian in this time period of it's history, to preserve it for future generations. The past owner felt that about me and that is the only reason he passed it to me. TAKE CARE, Rick