Marlin Ballard

[Niederlander]

Gentlemen, A friend has a Marlin Ballard that I believe is in .44 Rimfire (Henry?).  The bore is sewer pipe, but he'd like to get it rebored to something shootable.  Would something like .45 Schofield work?  I have no idea, but thought maybe someone on here had already done it.

[Major 2]

I believe he would have to step it down with a rifled liner.
  Perhaps 38 for * enough meat in the barrel wall.
Obviously, convert to CF If the rest of the action and wood is decent and Black Powder only.

Perhaps 32/20 though 38 would be cheaper to reload.

* Edit: with further though "IF" it is a heavy Octagon barrel
there may be enough meat to bore and reline to 44-45 cal. 

[Cap'n Redneck]

Some of the earlier Ballards were made with reversible firing pins that could be flipped around for centerfire or rimfire cartridges; you take out the breechblock, unscrew the screws holding the two breechblock-halves together, and place the firing pin in the desired slot.
These split breechblocks are not considered to be very strong, and are best suited for blackpowder "pistol cartridges".

I'm thinking the present "sewer pipe" barrel has to be bored out to smoothbore to assess whether or not it can be rifled to .45 Schofield or must be enlarged to .56-50 Spencer CF?
Re-lining the barrel to .44 Russian, .44 Special or .44-40 could also be an option.

Measure the outer diameter of the barrel (across the flats if octagonal) at both the breech-end and the muzzle, and contact some of the gunsmiths / firms offering re-boring / re-lining for their view on available options and some price quotes.

[Coffinmaker]

  PLUS ONE fer Cap'n Redneck 

Must understand though, returning the Ballard to serviceability ain't gonna be cheap.   
 

[Niederlander]

He knows that.  He's just always liked them and would like to get it shooting again.  Heck, if any of us wanted cheap, we'd buy a Handi-Rifle!  Wouldn't be anywhere near as fun to shoot, though.

[Drydock]

I would call Lee Shaver and see what he says.

https://stores.leeshavergunsmithing.com/