aether_Tech wrote:
Is it 10mm? Is it some weird Rossi only thing? It's not 3/8 as far as I can tell (since a normal 3/8 just slides through.) The Skinner sight that supposedly works with the old 10mm Rossi dovetails definitely didn't work, totally different angle. Even measuring this thing got me like 9.6mm or something weird....
First, I'm mildly amused you got the Cass Elliot quip. I sometimes think only folks my (very old) age get 'em.
Next - It is very common for dovetails to be fitted, or rather, the sights to be fitted to dovetails. This holds true for "standard" .375" dovetails which are usually cut a bit small, more like .268"-.270"-ish. (<== my hands on shop experience from the 70's thru 90's). You have to look at things a bit, but the usual best way to fit those is to take material off the bottom of the sight until it fits the dovetail. You can do that, and its easy, if _AND ONLY IF_, the part of the sight above the barrel will still clear. A leaf sight, like a Marble's or such, may or may not, but usually they do. I really can't remember one specifically that didn't but... I do recall putting a sight or two on the Bridgeport and re-cutting the dovetail, so it must have happened a few time.
How about when the dovetail is too big? Then things get "creative". If its just a tiny bit big, then you can push up metal on the bottom of the sight with a sharp punch until the fit is tight, clean everything really well, and red Locktite the sight in place. That works, and I've got a few in my own "arsenal" that are fit that way and never give a lick of trouble. If they're more than just a little loose, say.. with a .005"-.010" gap between the bottom of the sight and top of the dovetail's flat, then a grub screw put into the sight will hold it in place. One will do, but some 'smiths will use two - left 'n right. That depends on the situation, barrel diameter, sight, etc etc etc.
What if the dovetail is really, really big, some oddball item. Then you have to put on the ol' thinking cap. Consider the gun, its intrinsic value... if its something that should stay original, then search your butt off for the right sight. If its just a shooter, there's a variety of ways to do things. If there's enough barrel material, You can drill/tap for a base with a dovetail, and raise up the front sight to match. You can silver solder, or weld material to a sight's dovetail and re-cut the edge. If you think there's enough "side material" to hold the sight, you can shim it and use a grub screw - but that's dicey. Did that on .22's but, that's all.
The lever gun will look funny with a raised up rear sight on a base, and then you create a new problem with the front sight. From your situation, I'd take a real, real close look at the Skinner you have, which is too big, and see if the bottom can be shaved so the dovetail fits. DO NOT shave the sides, unless you are CERTAIN that there will be too little clearance for the horizontal parts of the sight.
Avoid shade tree methods of - altering the barrel by hammering the upper edges of the dovetail to try to tighten things, welding, raising up metal on the bottom of the dovetail, etc etc. Those are the mark of a true wearer of the "Bubba 'Smith" name tag.