Soule or Marbles?
It is the correct base for the 1895CB & does have 2 mounting holes....I just used the long stock screw for temporary setup. Since my last post I mic'd everything on the base/staff & found it perfect......
.....it appears the Marlin's tang is the culprit & not crowned perfectly. I used some brass 0.010 shim stock on the base low side & stoned the high side 0.002" to get it square. Now I'm comfortable drilling & tapping the front base hole.
It's a Marlington. I read lots of recent reviews of Marlin's latest offerings & most agree they are improving slowly. There was a period several years ago when all reviews seemed negative. This particular 1895CB does not have the sloppy wood to metal fit I've seen online but while improved, the finish has not equaled the true JM Marlins of yesteryear. I was quite surprised the tang contour was asymmetrical enough to cause 0.0125" shift at the base which caused 1/8"+ cant at the peep (lowest elevation) when everything outwardly appeared normal. We'll see how she shoots.......
Just reread my posts & see the need for clarification that might benefit future Marlin buyers. The tang crown WAS profiled correctly BUT the tang screw hole was machined slightly off center. This had the effect of shifting the Marble's base on the tang crown. Once the problem was identified it was an easy fix to level the sight base with shims, but made locating, drilling, and tapping the base front hole a challenge.
I guess it depends on how much you are off on windage. Most of the time the Marbles has enough windage adjustment to zero the rifle. However, given the off center mounting hole on your tang, it could be that you'll need to drift the front sight a little. Remember, with the front sight, you move it the opposite direction that you want to move your group. That is, if your group is left of center, move the front sight left in order to move the group to the right.