Finding the proper size Smith Carbine bullet?

[Collie]

I recently picked up a very nice original Smith Carbine with a bore that looks almost new (it wasn't relined). The problem is, I haven't been able to work up a charge that shoots well with my gun and bullet combo. I'm using Eras Gone bullets as cast at about .518" from pure soft lead and the hard black plastic cases. When I load the cases, I make sure to leave no air gaps and to seat the bullet so that it is just barely touching the throat of the barrel. Here is my current load:

• 25-40 grains of Schuetzen 2Fg powder, tested at 2.5 grain incriments
• 50 cal wads to fill up space as needed in the cartridge
• Cast Eras Gone bullets at .518" cast from pure lead
• Schuetzen musket cap
• Black plastic cases like you find on Dixie or Lodgewood, with the brass rivet added to the touch hole.
• SPG bullet lube, which seems to be doing a very good job at keeping the fouling soft

I'm thinking that I need to try sizing the bullets to be .001" - .002" over the grove diameter, but the problem is these originals have three grove rifling and I can't get a good measurement with the odd number of grooves. Does anyone know how I can get a good measurement of the groove diameter and the land diameter? Also, anyone out here have a good load for these original Smiths that works for them? I intend to use this in N-SSA competition and what to hear what works for everyone else.

 

[gemmer]

Find a machine shop that has a three flute anvil micrometer or plug gauges.

 

[dave951]

I recently picked up a very nice original Smith Carbine with a bore that looks almost new (it wasn't relined). The problem is, I haven't been able to work up a charge that shoots well with my gun and bullet combo. I'm using Eras Gone bullets as cast at about .518" from pure soft lead and the hard black plastic cases. When I load the cases, I make sure to leave no air gaps and to seat the bullet so that it is just barely touching the throat of the barrel. Here is my current load:

• 25-40 grains of Schuetzen 2Fg powder, tested at 2.5 grain incriments
• 50 cal wads to fill up space as needed in the cartridge
• Cast Eras Gone bullets at .518" cast from pure lead
• Schuetzen musket cap
• Black plastic cases like you find on Dixie or Lodgewood, with the brass rivet added to the touch hole.
• SPG bullet lube, which seems to be doing a very good job at keeping the fouling soft

I'm thinking that I need to try sizing the bullets to be .001" - .002" over the grove diameter, but the problem is these originals have three grove rifling and I can't get a good measurement with the odd number of grooves. Does anyone know how I can get a good measurement of the groove diameter and the land diameter? Also, anyone out here have a good load for these original Smiths that works for them? I intend to use this in N-SSA competition and what to hear what works for everyone else.

First, if you’re going to use it in N-SSA, forget the Eras bullet. While maybe historically correct, there are much better choices. Moose has a couple good choices and Accurate makes a good one as well. Most folks I know with originals shoot a .518 bullet and not always pure lead. You should get very good accuracy with the Moose bullet, 25-30g 3f Swiss and just enough filler to get the bullet right at the lands. Also, virtually nobody uses SPG. Most use either MCM or a personal concoction. And yes, lube can have a tremendous effect on accuracy.