sight dovetail problem, Win. 1873

[papabear]

I bought an original 1873, made in 1893, with a newer Marbles 60 series rear sight.  I removed it to replace with an original Winchester sporting rear sight I had.  I find that the Marbles sight has a smaller than the  standard Winchester 3/8 in.  dovetail, obviously not for a Winchester.  It appears that the barrel dovetail was either welded up and recut smaller ages ago, or possibly filled in with solder, recut, and then the smaller sight fit OK.  Whatever was done exactly is not readily apparent to me, and has aged a lot, but there is a shiny surface to the bottom of the dovetail which makes me think of solder, but it seems awful hard for solder.

Problem: How do I reshape this dovetail to the larger 3/8 in. size to fit my old Winchester sight?  I am no gunsmith, just a hobbyist and farmer.  No access to milling, etc.  Could I use a 3 cornered file and do it by hand?  Do I need to buy a special file from Brownells or somebody for this particular dovetail with the correct angle on the bevel?  Thanks.

David M
The Iowa farmer

[gunnut69]

If all you cut is the bottom a three cornered file with 2 sides ground safe will work IF you exersize a lot of care. If the dovetail doesn't match exactly, close will do.  The normal 3 cornered file is tapered, a pillar of paralell sided one would be better. They can be had with 2 sides already safe from Brownells but for 1 dovetail, if your very carefull, it'll work. GO SLOW!  It's easier to take it off than put it back.

[papabear]

gunnut69, thanks for your reply.  I still have some confusion.  You say if I want to just cut the bottom, to use a 3 cornered with two sides ground safe (and parallel sides).  It appears I need to increase the depth slightly, as well as the width at the bottom.  The top of the present cut is buggered and crude and is plenty wide enough.  So you are saying to use a file that works on one side only, and do depth and width separately?  

Also, it seems the sight itself measures wider on one side of the dovetail by maybe .003.  I know that my work will not be this precise, but is it true that these Winchester (and other) sights /dovetails are cut tapered, and sights are to be inserted from R to L, and driven out from L to R?

[gunnut69]

As the depth of the dovetail cut in the barrel is deepened it will also have to increase the width... The dovetail on a sight is normally a bit smaller ob the left side(looking at the rifle from behind) as it helps get the sight started in the barrel cut. The paralell sides avoid altering the 'shape' of the dovetail cut. Dovetail files only cut on a single side so that one can work the bottom/sides seperately..