Hello,
It's been a long time since I started this post, but I thought I might introduce a little more concise method of identifying the five variations of Gen 4 M9s.
See if you can identify the pictures above with this better (IMHO) method.
The pictures above are not in the same order.
Marv

Gen 4 M9
Five variations

(in the first example: the B in PHROBIS lines up
vertically with the S in U.S.A.)

1. B/S wide USA flat sided O

2. B/S wide USA oval 0

3. B/S narrow USA

4. U/T S/P

5. I/A

Hope this helps :smile: