Don't think you want an 1871 Mauser unless you have a hankering for black-powder or equivalent loads. A model 1871/86 model will have a .446" groove diameter barrel. The model 1871's and 1871/76's have .457 groove diameter, but will accept only a .446" bullet, .011" undersize. That means paper patched undersized bullets and black powder only, to expand the bullet to fit the grooves.
The standard chamber will only accept a .446" bullet.