Hello All:  I've got a 50-70 maynard civil war gun with the last patent date of 1859. I went by the drawings in Cartridge Conversions for the 1865 Maynard and made a case. Unfortunately, the gun will not close. Either the rim needs to be thinner, or the rebated end needs to be turned down more. Unfortunately, that dimension is not listed. Anyone know the proper rim thickness and the diameter of the rebated end? Thanks, Dan

Yes, that is what I did and found the rim thickness should only be .032" which is quite a bit thinner  than what was stated in the Cartridge Conversion book. Anyone know what the flash hole diameter should be? Thanks, Dan

That's a great site! I've been teaching my son to run a lathe, and this was a great project for him and me. He's turned out some nice cases. We just need to know the size of the flash hole. Also, how is the hole sealed so the powder doesn't fall out?  Thanks, Dan

First of all your case isn't a 50-70. Or at least you better hope it isn't or you will feel like your arm is being torn off when you touch that thing off. 
If it is a civil war model 2 it is a 50 caliber percussion. It takes a bullet of around 515 -517 weighing at around 300gr.And from 22 to 40 gr. of Black Powder, depending on the type of case you produced. 
Believe me, I've hunted with these guns and you will not believe the damage done on a deer from 50 to 100 yards with that load.
Like froggie suggusted I kwould buy at least one case from a respected suttler and use that as a pattern for what your cases are supposed to look like. They are made in two types. The first one is for target lite loads and has a reduced capacity allowing only about 24 grs of powder. These work very well but the original sights will not line up well for elevation and a higher front sight will have to be arranged.
The second type is full capactity and takes about 40 gr of powder (I use 3F) I have found that the original first sight leaf will normally be on at 100 yds with that load. The other two sight leafs will be close on at 300 and 500 yds (I think that is right But, I haven't shot much at those distances with the carbine). 
Your carbine with the right load and bullet can be far more accurate than you would imagine. It's been known to put 5 shots off hand into one ragged hole at 50 yds. And it isn't too hard to hold minute of grapefruit at 100 yds.

The .031" rim thickness is correct. The overall case length should be about 1.200" with a 3/4" dia rim and a .545"-.546" body diameter. The flash hole should be .040" diameter, a #60 drill or 1mm drill will work. The correct bullet diameter should be from .515" up to .520". Best results will most likely be .001 over groove diameter. Civil War bullets were as large as .525". This should get you shooting.

There were two 50/70 chamberings in the later sporting model Maynards and they were not interchangeable. The 1873 50/70 chambering is quite rare and was a straight case slightly larger in diameter and longer than the Gov't cartridge. 1882's were chambered for the 50/70 Gov't cartridge. The Civil War guns were not 50/70's.