not sure if it helps but most military issue and surplus 1911 mags i have seen have the bottom stamped like this.. if they are stamped colt i believe those are comercial mags.. im sure many companys made them

 

Very late post Vietnam contractor magazines from around the desert storm era, near the end of the 45’s service life. Caddilac has a good post. Most WWI era mags were unmarked, but had some distinctive characteristics- weakness in the feed lips was addressed with a tempering process that left about 1/3 of the mag in the white - so called two tome mags, also seen on most colt semi auto mags into the 1930’s. as someone mentioned there were some foreign knock offs of the late contract mags which wer3 of poor quality

 

He had some of those in the store, still in wrappers, he claimed that he saw them in Viet Nam. I have a few and they tend to jam, so I am switching over to

original old stock that I can find. Would love to find some remington rand made mags.

 

W.W. II era magazine contractors.

(Military magazines have the "letter" on top of the toe of the magazine.
L - on top lip of base - M. S. Little Mfg. Co., Hartford, Conn.

L - on top lip of base - C-L on bottom lip of base - M. S. Little Mfg. Co. (subcontracted for Colt)

R - on top lip of base - Risdon Tool & Machine Co., Naugatuck, Conn.

R - on top lip of base - C-R on bottom lip of base - Risdon Tool & Machine Co. (subcontracted for Colt)

S - on top lip of base - Scovill Mfg. Co., Waterbury, Conn. (Scovill acquired American Pin Co. in 1923)

S - on top lip of base - C-S on bottom lip of base - Scovill Mfg. Co. (subcontracted for Colt)

G - on top lip of base - General Shaver Division of Remington Rand, Bridgeport, Conn.
I have some stamped “R”, and some “C-S”,
I believe.

 

Keep in mind there are some relatively new USGI mags that someone tried making within the last 20 years that they screwed up the positioning of the holes to count rounds. They have stock numbers on the baseplates. Apparently some no olname company tried for a US contract, biffed it, and they have been selling for less than 10 bucks forever.

 

There are some mid 80's Checkmate made mags that were made under contract for the Government. The CMP got a bunch of those about 15 years back and sold them for about 10 bucks a mag.

There is also a bunch of chinese made US contract marked mags that you will see at gunshows for 10 or less. They are junk and should be stayed away from.

 

The mag is the weak link in most 1911s. I would just buy some solid 8rd like Wilson.