Question on a SG serial overrun carbine.

[ncblksmth1]

I just picked up a Inland which has the X suffix and is a duplicate serial number. It does have a curious mark on it.

On the front receiver ring just after the M1 mark there is a period. The line reads like this.

http://i1338.photobucket.com/albums/o682/ncblksmth1_1960/Inlandcarbine1_zpscab4ce0b.jpg (http://s1338.photobucket.com/user/ncblksmth1_1960/media/Inlandcarbine1_zpscab4ce0b.jpg.html)

Anybody have any idea why this period is there?

Thanks in advance
Bob C.

[jimb]

Mine has the same marking. There are several variations of this marking depending on manufacturer. CAL.30 M1, CAL. .30 M1, CAL .30 M1 and CAL .30 M1. for example.