Two Questions On Back Sight

[Jimminardi]

When looking at my auto ordnance M1 today I saw a cut on the top of the back sight. It is right on top and about 1/16 of an inch deep. What is this used for? Is it for sighting for longer ranges? They must have put it there for a reason because it took extra time to cut it out.

My other question is why there are little dents in a circle around the hole in the back sight. Why were these put there?

These questions are really bugging me so I'd really like some help. Thanks

[Motorcar]

Pick up a copy of "American Thunder" if you can find one. On page 220 the revised "L" sight is described in detail. If new production holds true to original then the notch at the top edge is for a range of 250 yards and the small aperture sight is for 150 yards. As for the dents, someone of much more knowledge than me will have to help out with that one. Congrats on the purchase, I love my '27.

[PK.]

The "little dents in a circle" are to reduce glare

[full auto 45]

Here is a picture of what you are talking about. This is off my M1.

rear site

http://mikesmachineguns.homestead.com/files/tn_peep_site_ring.jpg

[must]

http://www.machinegunbooks.com/forums/invboard1_1_2/upload/html/emoticons/cool.gif I have a AOC parts set that I had PK remove the rear sight & install it on my WH M1 Thompson that he was working on. It had the noch on the top & the circle of dents around the hole you look though also. Frankly I never noticed these things before (probably because I was having too much fun shooting it). My front sight was also a AOC.