Hi!,
I have a goodly number of NOS, in-the-wrapping, USGI M1icon Cabine barrels that I am unwrapping and going through the markings and stampings.

This one is a little difficult to precisely ID, with the minimal stampings.

- NO front/top of barrel markings
- large letter 'B' (only; not 'BI') on the underside of chamber flat area
- Ordnance cannon wheel stamping, rear of underside chamber flat area
- capital letter 'M' on the side/top of the barrel chamber
- T4 front band has stamped capital letter 'Q'
- witness line mark on bottom of the chamber
- 'WI' marked gas piston
- NO other markings on swaged gas cylinder body/front/sides
- tube is 4-lands/grooves
- flat muzzle

.....my guess from the markings/stampings visible is an GM-Inland Div.(prime contractor) spare barrel made by GM-Brown-Lipe-Chapin Div. as the subcontracted actual manufacturer, though the 'B'(only) stamping is troublesome......I looked VERY closely, and while it may be possible that the expected missing 'I' is just super faint and readily discernable, it doesn't appear so??

Anyway, have a look through the attached pictures, and I'd greatly appreciate any thought sor comments!

- TomH