G&R Tactical
Page 1 of 3 123 LastLast
Results 1 to 10 of 23

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

  1. #1
    Join Date
    Sep 2018
    Posts
    21
    Feedback Score
    0

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

    I've been a member here for a year now, and am just now getting around to making my first post lol. I'm fairly active on other forums, and am hoping to learn some here as well as contribute some. So this is my first contribution:

    While cleaning and refinishing a bunch of used USGI mags I recently bought, I came across 4 that had bad base plate retaining tabs, and figured I would try modifying them into 20 rounders instead of just tossing them. I decided to do this purely out of curiosity and boredom. Unless you are in a ban state and have preban mags that are damage, it's really not practical to do this considering how cheap and plentiful mags are right now. Unless of course you are like me and this is the kind of stuff you like doing in your spare time though.

    Started out by getting a rough idea of the needed length by using a straight 20rd mag, drew some guidelines, and got start cutting.







    Using a file, I cleaned it all up, evened the sides, and rounded the new tabs. I cut the spring off at the 11th coil, inserted the spring and follower back into the mag, laid the base plate in place and slowly knocked the tabs down.







    After assembling the mag, I was only able to load 18 rounds into it, so I disassembled and took around 1/2 inches off of the follower.



    Moment of truth!!



    Okay, this pic was taken before I made the modification to the follower haha but it is now a 20 round mag. It seats on a closed bolt without having to smack it, and although I haven't tested function while firing, I was able to successfully manually feed through all 20 rounds.



    I'll do some live fire testing this weekend and report back.

    Last edited by Monkeydo; 09-10-19 at 13:23.

  2. #2
    Join Date
    Jan 2018
    Posts
    1,718
    Feedback Score
    0
    Pretty neat!

    Before you modify the other ones you might get the front and rear heights off someone who has one of the curved alloy 20's. I suspect a 20rds Mini-14's dimensions would work too.

  3. #3
    Join Date
    Aug 2009
    Posts
    3,147
    Feedback Score
    8 (100%)
    Any thought to cutting them down just enough for new tabs, making them 26-28rd mags?
    - Rhino

  4. #4
    Join Date
    Sep 2008
    Posts
    1,024
    Feedback Score
    3 (100%)
    Sounds like something we'd do during the Ban era. Now most would just flop 'em into the trash and buy more. But these skills may come into demand after 2020 . . . . .

  5. #5
    Join Date
    Dec 2013
    Posts
    783
    Feedback Score
    2 (100%)
    Really cool project.

    #thumbsup
    "Just throw Krylon on it"

  6. #6
    Join Date
    Dec 2012
    Posts
    1,065
    Feedback Score
    0
    Nice work. Welcome to M4C.

  7. #7
    Join Date
    Sep 2018
    Posts
    21
    Feedback Score
    0
    Quote Originally Posted by jsbhike View Post
    Pretty neat!

    Before you modify the other ones you might get the front and rear heights off someone who has one of the curved alloy 20's. I suspect a 20rds Mini-14's dimensions would work too.
    That's not a bad idea. I'd suspect I got pretty close to the size of the Mini-14 mags. I've seen some 20's that are much longer, but I believe they use standard length followers, and is the reason for the extra length.

    Quote Originally Posted by RHINOWSO View Post
    Any thought to cutting them down just enough for new tabs, making them 26-28rd mags?
    I may with one of them. Knowing myself, I'd have trouble remember how many rounds the mag is suppose to hold lol

    Quote Originally Posted by Uni-Vibe View Post
    Sounds like something we'd do during the Ban era. Now most would just flop 'em into the trash and buy more. But these skills may come into demand after 2020 . . . . .
    Exactly. Hopefully it doesn't ever come down to me needing the skills, but it definitely doesn't hurt knowing how to fix a trashed mag and spreading that info in case of a future ban.
    Last edited by Monkeydo; 09-10-19 at 14:04.

  8. #8
    Join Date
    Apr 2016
    Posts
    30
    Feedback Score
    0
    What cutting instrument did you use?

  9. #9
    Join Date
    Oct 2012
    Posts
    3,981
    Feedback Score
    10 (92%)
    Quote Originally Posted by RHINOWSO View Post
    Any thought to cutting them down just enough for new tabs, making them 26-28rd mags?
    That would make more sense to me or maybe a nice easy to remember 25 rounds. Either way I wouldn't have cut the follower. Reducing the anti-tilt properties might end up being a bad thing. Nice job salvaging a magazine though!

  10. #10
    Join Date
    Sep 2018
    Posts
    21
    Feedback Score
    0
    Quote Originally Posted by boss_hawg View Post
    What cutting instrument did you use?
    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.

    Quote Originally Posted by GH41 View Post
    That would make more sense to me or maybe a nice easy to remember 25 rounds. Either way I wouldn't have cut the follower. Reducing the anti-tilt properties might end up being a bad thing. Nice job salvaging a magazine though!
    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.

Page 1 of 3 123 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •