Does anyone know what the average bore dia. is for a 50-70..I slugged my bore and got .513

The mold I have that came with the rifle is a 518????????????

Nominal is .512. My 1866 Springfiled is .518.

Same as ALK8944...modern made rifles usually run .512-513", the originals are all over the place, with something in the .516-518" being pretty common. the ammuntion was usually loaded with 513-515" bullets, but being soft lead and black powder, would usually bump up to fill even a .520" bore reasonably well.

Some wre even bigger...a whole lot of Sharps percussions got converted to 50-70 right after the "great unpleasantness" (I actually read that in a New Orleans news paper from 1869)..the ones with bores larger than .520" got relined, the ones .520" or under just got a 50-70 chamber cut into the existing barrel.

I'll look....found two Lee molds of differnt weights, but only the 450gr. had the deep lube grooves I wanted.

going to toss up a few links:
http://www.trackofthewolf.com/(S(jitkfrmhtqgru455vydyg055))/categories/partList.aspx?catID=18&subID=212&styleID=1140
http://www.gunaccessories.com/Lee/Molds&Melters/BulletMolds.asp

And i can presonally promise, our host (Bearthooth Bullets) makes a fine one in their 475gr.GC version...may not be a traditional BP type bullet, but if you are looking to hunt with that 50-70, order some.
http://www.beartoothbullets.com/bulletselect/index.htm

I have a 2nd model Allen conversion trapdoor rifle that I will eventually shoot. By-the-way, original Springfields, Sharps, and Remington rolling Block rifles in 50-70 are getting to be very valuable. Any of them in good shooting condition are going to be in the $2000 category and up. Lyman has a mold, #515141 that I am considering because it is reported to be very close to the original.

Lyman's # 48 loading manual is quite clear that this cartridge should not be loaded with smokless powder for use in original rifles. Therefore a black powder load will not only be vintage and safer, but will also help to avoid damage to a valuable rifle.

I belive that Buffalo Arms, www.buffaloarms.com (http://www.buffaloarms.com) sells loaded black powder cartridges.

Are the host bullets cast of hard alloy or soft lead?

My Lone Star rooling block likes 0.511 diameter bullets. Get much bigger than that and you have chambering problems. I've got quite a few bullet moulds for the 50-70 and I don't think any of them cast a bullet as large as 0.518.

A few years back, was a poster oh here that had an original Sharps carbine he wanted to shoot. I dug around on the 'net and though some old books, and found that tid-bit about some of the Sharps not being relined, just chambered the existing bore...if it was .515-520 they'd often rechamber rather than reline. Once they really got rolling with the conversion, was easier to just reline all of them, but at least some of them (early conversions) just got a chamber.

So there can be some old originals with bores as large as .520...his was big, (I think .519...can't remember). Do not remember how that was settled (but I think the decision was made not to shoot the old girl). Dead soft lead and a full charge of black would bump up and spin.

With some $ and time, might try a custom made hollow base bullet (can use a full .519" seated inside the case and expect it to chamber) or shortened cases and a custom heeled based bullet....but darned few of those originals are over bore, and even fewer people willing to risk them by shooting them very often.

My 50-70 , Higginsbauthem LONE STAR Roller is .511 , Green Mountain Barrel and I had Paul Jones, out in La La Land cut me a mold , bullet drops at .511 at 585 gr., Flat Nose PB cast from 30-1 melt

That bullet and rifle is wounderful ,

Using that bullet at 585 gr, a duplex load w/63 grains of GOEX FFg, and 5

grs of Reloader #7, I Shot a big cow bison with that in 06.......................

with a real big exit hole off side :)

guess I better get a sizer then...You probably right about the 518 inch not going to chamber..thanks for the info guys..