Fun with my peeps

Champion's choice makes this nifty adapter bushing that lets you use Euro-thread accessories in US-thread sights:

http://www.champchoice.com/store/Main.aspx?p=ItemDetailOptions&item=PH999

Great gadget, you can use the same iris on every aperture sight that you own. The only disadvantage I have found, is that if you have one of the German irises with a magnifying lens, the smaller opening in the US sights will cut off part of your field of view. 

Here's one In action - joining a Gehmann iris to a Williams sight, on an old HW 50.

Quetion about using the williams sight, the side screw is a lock once you have it sighted in? Basically, is it supposed to be tightened fully or should it be loose enough to be able to turn the elevation screw whenever you want?