Magazine makers' initials

[Patrick Chadwick]

I bought this heap of magazines for a multi-target competition. For which they will be altered to take max. 10 rounds.

Observed stamps are:
AI (lined above and below), BW, G-B, G-Q, IA, IS, IU, IW (in circle), M, MN, R-Q, (SP), SY-B, UQ, UU, O SG, 01 B

So, before I get to work, are any of these so rare that I should avoid irreversible alterations, bearing in mind that these are all well-used mags, not showpieces?

[Bruce McAskill]

Remember each one is worth a minimum of say $20. So if you want to us the ones marked IS, or IA as these are common magazines. The IS is International Silver and the IA is for Inland. The IS, is a common replacement type not associated with any carbine maker and so is the (SP). Maybe the BW will also fit into being modified. How many do you need to make into 10 rounds and how many of the ones I listed do you have?

[JimF4M1s (Deceased)]

The two Winchester BW, IW, mags may garner a few extra bucks. The others aren't rare.

[painter777]

Patrick,
I managed to find a homemade aluminum plug someone had made. I found in a mag from a box of mags I bought years ago. I pulled the bottom plate off, removed it and stuck it in a parts tray. The mag and spring were still intact. This could easily be copied by using wood.
Pull the bottom from a mag and make a wood block that will fit inside (measurements below). You won't have to trim the spring as the plug will make the spring think there are already 5rds in. Slide the mag floor back in place. Double check it, so it does take up the space for 5 rds (Been a long time since I pulled this apart). You'll still have a traditional look of a 15 rd magazine.

Measurements:
Needs to stand 1-7/8" tall
Wide: 1-11/16"......... Equal to the ID of your mags.
Depth: 5/8" ........... Equal to the ID of your mags.

Your Floor plate will make a good traceable template on the wood, but you'll still have to detail sand to fit inside. There will be a front side and backside to the plug.
Sand the outer corners of the wood plug to mimic the inside profile of the mag. It will be... Very similar to the shape of the floor plate, but have a smaller footprint. Should be just enough to fit securely inside the mag.

Cheers,
Charlie-Painter777

[browningautorifle]

Our laws require 5 rds for a carbine and I too have done scads... I use steel strapping bent into an upside down "U" so the flat is against the follower. The legs run down the outside of the spring and the whole thing lies about three coils of the spring from top. I also found all mags a bit different, you couldn't assembly line them or you's get some that hold six rds. The top coils of the spring are integral to the whole deal. It's like the Colt factory block for their 20 rd mags except upside down to them...

It takes time but when they're done they all feed perfectly.

[Patrick Chadwick]

Thanks to Charlie and Jim for those tips! I always like to avoid irreversible alterations.

---------- Post added at 09:56 PM ---------- Previous post was at 09:48 PM ----------

How many do you need to make into 10 rounds and how many of the ones I listed do you have?

It is really surprising that in a heap of 25 mags there are 17 different markings!
However, I need 18 competition-fit mags, so most are going to be altered.

[browningautorifle]

in a heap of 25 mags there are 17 different markings!

I had 113 Garand clips and had 43 different markings...they made a lot of that sort of thing once. Not so surprising...

[BEAR]

Our laws require 5 rds for a carbine and I too have done scads... I use steel strapping bent into an upside down "U" so the flat is against the follower. The legs run down the outside of the spring and the whole thing lies about three coils of the spring from top. I also found all mags a bit different, you couldn't assembly line them or you's get some that hold six rds. The top coils of the spring are integral to the whole deal. It's like the Colt factory block for their 20 rd mags except upside down to them...

It takes time but when they're done they all feed perfectly.

When I purchased my Colt SP1 AR15 in 1971 it came with 2 twenty round magazines that were blocked to 5 rounds for hunting purposes. There were instructions on how to remove the blocks. I understand that later on Colt pinned the bottom of the magazines so they couldn't be removed.

[browningautorifle]

later on Colt pinned the bottom of the magazines

You are correct, but determination over comes many things...my brother...

[painter777]

A length of 1"x 3" will get you rolling. Face sand to get it down to aprox 5/8" and the side to get down to about 1-3/4".
Round off the edges to fit inside mag profile. When you can slide one in, try inserted at 2", to see if correctly eliminates space of 5 rds.
Once you've got the profile, just cut to needed lengths.
Country boy way........... but trust me it will work ;-)

Grab your belt sander....

Cheers
Charlie-P777