I would like to shoot 44 colts out of 1873 in 44 special. Has anyone done this before? What type of modifications would I need to make to the 1873?

I have no clue what would be required for the rifle. Several shooters at the Historical range have done it with hand guns.

It is discussed here for hand guns.

http://www.sixguns.com/range/cartridgeconversions.htm