Do you measure from barrel flat to top of sight, or from bottom of dovetail? Brownells has some stuff I want to try and not sure how to measure that height. Thank you

I believe it is measured from the top of the barrel flat to the center of the sight. But the real important question is how low can your rear aperture go?

I don't know that there is a standard or convention, but I know that Lymans are spec'ed from the bottom of the dovetail to the center of the sight globe.

You just need to find out how a particular manufacturer does it.

Paul

30338 - I will defer to Paul's comment. He has been doing his homework on this a lot more than I have.

Still trying to figure out how you can accurately take the necessary measurements with a sight already in place. I use a caliper and Mark I eyeball.

Paul

Maybe measure to the bottom of the barrel, then measure from bottom of barrel to bottom of dovetail (sight removed) and subtract? But in choosing a sight height, super precision is probably not a big deal.

Ah, but see my post, removing the current sight to measure would be cheating!

Paul

I can usually get the tip of my calipers in the bottom corner of a dovetail IF the barrel is octagon. Not so hot for round barrels.