Buffington Backsight----

What is the purpose of the slots milled into the back of the slide on this Buff?

https://www.milsurps.com/images/impo...94586847-1.jpg


There is a difference in the locking screws, too.

https://www.milsurps.com/images/impo...94586849-1.jpg


I didn't notice the difference in the slides until I decided to switch out the locking screws---since I need one that works mounted on the rifle.
Any help appreciated.
-----krinko

That is a slide off the first type Buffington sight which had a working rack and pinion adjustment on it.It was not a successs and dropped around serial number 290,000.The early sight has the small the small screw,the later or second type Buffington has the larger screw.