Modifying a broken 30rd USGI mag into a functional 20rd mag

[Hammer_Man]

I have to applaud your creative thinking, and execution. Have you looked into finding 20rd followers? I think they are a different design than the 30 round followers. For example, all my 20 rounders index the top round on the opposite side of the magazine body as my 30 rounders. Regardless, I look forward to reading your range report.

[Monkeydo]

I have to applaud your creative thinking, and execution. Have you looked into finding 20rd followers? I think they are a different design than the 30 round followers. For example, all my 20 rounders index the top round on the opposite side of the magazine body as my 30 rounders. Regardless, I look forward to reading your range report.

Thanks! I thought about using an aluminum follower, but figured I'd try the green follower that was original to the mag first. The green followers do have the round mold on the same side as the original aluminum followers. I've always wondered what the reason for the molds being on different sides is. The magpul's are on the original side as the aluminum, black, and green followers, but the tan followers are on the opposite side, as well as Okay Ind's new E2 mags (opposite side). I haven't been able to find anything out on why this is.

I'll definitely keep you all posted! Thanks again.

[jsbhike]

I used a Dremel 409 wheel. If I would have had a 426, I would have used it. Those 409 wheel are nasty and shatter easily.

Yeah the non reinforced kinda suck. I tend to get the aftermarket Christmas gift pack cut off wheels and save the reinforced ones for tougher material/complicated cuts.

I wonder if diamond cut off wheels would work better or not? They are the toughest. Fortunately haven't had one of those fly off the mandrel which would be exciting.

[boss_hawg]

I used a Dremel 409 wheel. If I would have had a 426, I would have used it. Those 409 wheel are nasty and shatter easily.



I have very few 20 round mags, and even though I don't use them a lot, figured I'd add another to the mix. Idk, I guess I'm also OCD about the mags needing to be in 10 round increments or something lol. The follower may end up having tilt issues. This isn't a mag I'd trust with my life anyways though lol. I'll run it through it's paces, and if there's any issues, I'll switch things up when fixing the the next one. I have 3 more with broken, or "breaking", tabs. Haven't decided what I'm going to do with them yet, but the way this one performs will help me make the decision. A 25rd may be next.

Nice cuts! I don’t trust myself with a dremel.

[mack7.62]

You might use a Gen 3 Magpul 20 as a model, also I don't think the straight 20 follower would work as good in a curved 20.

[Monkeydo]

Nice cuts! I don’t trust myself with a dremel.

Thanks! It’s taken a couple years for me to get where I trust myself lol and I still have it get away from me every now and then, especially with the 409 wheels. You can always cut away from where you want to end up, and clean it up with a file afterwards. I had to clean this one up and shape the tabs with a file.

[GH41]

Thanks! It’s taken a couple years for me to get where I trust myself lol and I still have it get away from me every now and then, especially with the 409 wheels. You can always cut away from where you want to end up, and clean it up with a file afterwards. I had to clean this one up and shape the tabs with a file.

I have no idea how well equipped your shop is. This is how I would do it.

With hole saw in drill press cut green hole through both sides at once.
Cut red line with chop saw
Cut blues lines with bandsaw
Nothing wrong with what you did but doing it this way, from one side, would eliminate the difficulty transferring the layout accurately.

[jsbhike]

What purpose does the hole serve? Reference to base the cuts off of, cut down on flex/chatter, or?

[GH41]

What purpose does the hole serve? Reference to base the cuts off of, cut down on flex/chatter, or?

The outer diameter of the hole allows you get at the cut line between the tabs with the bandsaw.

[Dennis]

Very cool idea!

I like the idea of 25ish round mags leaving a full sized follower. Of course I'd needlessly drop a Magpul follower in it anyways.

I sorta wish I had a broken mag to do this too... All my broken GI mags happened at the other end.

Now I have to resist cutting on a perfectly good mag!

Dennis.