I am no expert on the subject, but I think the Mk III is much more desirable as a shooter. The breech block on a MkIII locks in place and the breech block on the Mk II is only held in place by a spring detent. Also, as I recall, the Mk III has a steel bbl while the bbl on the MkII is (I believe) iron - as found on the earlier muzzle loading enfield.
Bbl condition is, of course, always important.
I own and shoot plenty of Sniders.
14 and counting of all MK's.
They are one of my passions.
Years ago, I used to shoot with the Ontario Rifle Association and pushed these babies out as far as I could.
I have always found that the MK II**'s to be the most accurate and that the Short Model - 2 band was the top of the heap for accuracy due to it's superior rifling. (1x48 twist)
I read one time that it had something to do with the harmonics of the iron barrels over steel.
There is a Snider Facebook group that I formed a year or so ago if anyone is interested with enthusiasts from around the world.
ht tps://www.facebook.com/groups/707539612638515/



























