MVA vernier sight on 1895 cowboy

[newfie bullet]

i'm planning on getting a MVA vernier sight for my 1895 cowboy. planing on shooting cast 350 , 405 and or 430 bullets over trailboss ,unique or imr 4198. lighter loads that will shoot good with the bullet molds powder i got on hand.was thinking the #108 or the#130 . how far do you think i will get out of the #130 before i runs out of adjustment on the staff?
do the MVA vernier sight base use the existing tang screw hole for mounting plus one drilled hole or do the gun have to be drilled with two new holes to mount on the tang.
alan

[Randy Bohannon]

If it is pre D/T ‘d MVA has bases for it ,if it is a pistol grip you lose some elevation.The MVA #115/116 front sights are super nice 👍. You should see reasonable accuracy out to 300 meters perhaps a bit more without much fuss with those sights and loads on a calm day. They at their best with a soft bullet and case full of Old Eynesford 1.5 in a 45-70

[38-72]

If your Marlin as serial numbers on the top tang, do not drill thru the numbers. The Feds get mighty upset about de-facing serial numbers.

Call MVA, they are very helpful in get you the right sight and bases.