Measuring Dovetail

[nealio]

I have bought a rossi rifle that has the wrong buckhorn jammed in the dovetail. I cant seem to find the right one so I am just going to order a universal, however I need to know how to measure the dovetail. The universal sights come in:


SPECS: Dovetail Model - Total heights: #63 and 64, .275" (7.1mm) - .505" (12.4mm); #63H, 64H, 66H and 67H, .350" (9.0mm) - .630 (16.0mm); #65, 66, 67 and 68, .300" (7.6mm) -.510" (12.9mm).

Can anyone explain how to measure this?

 

[trevj]

Unless I am misreading this, all those are the heights of the various sights, not the dovetail sizes.

Grab one of the digital calipers from Crappy Tire. Money well spent.

To accurately measure the width of a dovetail you need two rods of the same diameter Drill shanks work OK) that are small enough to contact both the side and the bottom of the dovetail, you then measure the gap between them and do some trig. If you really must, the formula's you need can be found online.

For real world purposes, measure the width of the widest point of the dovetail, and find the closest size that you can in the parts catalog. For those, it will be a 3/8" width, nominally.

Rossi Pump? Most of them are straight rips of older Winchester pump guns, no? Maybe compare and see which of the heights is recommended in the catalog. Bets are off, if the front sight was replaced, too, but worth a look.

Other than that, measure the diameter of the barrel and the height of the front sight, do same for the diameter of the barrel where the rear sight sits and calculate how much height you need. The height should be to the 'notch' not the top, IIRC.

Does the current rear sight need to adjust lower or higher? Any numbers on it? That would be a good place to start.

Calipers! Good investment! You need a set!

Cheers
Trev