I have seen mention of the 20 round Colt mags with a one in a circle on the side, but I have seen no clear explanation of where these were from. I have one of these.  It is marked AR-15 cal.223 Colt with the Pony emblem on the baseplate. It has no other markings, no "UI" either.

My guess is these were early commercial mags.  Anyone know what these are.   It is in like new condition. I bought this as a using mag, but if it is something I should not be wearing out, I will find something else for shooting.

ar-wrench,

This was discussed a bit ago.  On page 2 I believe.  I'll try a hot link. (My first so hope it works)

[url]http://www.ar15.com/forums/topic.html?b=3&f=17&t=170483[/url]

As far as using the mag or not...My Dad always said, "Hang it on the wall...It'll be just as useless tomorrow as it is today."

Sly

I read the earlier thread and lacking more proof It appears in error.  The "circle 1" mag I have was not made by the same equipment as the UI mags I have from the same time period.  The forming die used is very much different in the area of the rear stiffining ribs.

Universal Industries may well have been the prime contractor for "Colt" mags, but the specimen I have was made on different machinery from all other UI mags I have seen.  Even at first glance, they look as different as USA mags look from USGI mags.  The Circle 1 looks to be a higher quality mag than the UI.