Weld Up Your Own Big Stick

[StealthyBlagga]

Someone PM'd me asking how I made a 62-round big stick magazine for my Colt-type PCC, so here are the step-by-step instructions.

 

I started with a couple of Uzi magazines; they are cheap and don't have the rear rib like the Colt mags (simpler to modify). I can live without last round hold open... if the mag is big enough, I should never reach the last round. To start with, I had a friend mill the mag catch slot in the top magazine and I squared off the bottom:

 

 

Next, I cut off the top of the second magazine just below the side indentations:

 

 

 

Before welding the two tubes together, I fabricated a backing block by beating on a piece of 1" copper pipe:

 

 

 

 

Now for the worst welds you will ever see (fortunately Dremel sanding drums can hide a multitude of sins):

 

 

 

I cleaned up the inside of the tube with a couple of extra-long files from Harbor Freight.

 

Next, I needed to join the two standard springs together into one long spring. I calculated the spring length to get the same ratio of uncompressed spring length to tube length, cut top and bottom spring to preserve the floorplate and follower connections, and joined the two springs using a piece of brass tubing; I filled the tube with soft-solder flux, assembled it over the two spring ends, heated the tube and allowed lead-tin solder to flow in and fill the tube. The spring never gets hot enough to lose its temper, and the join is quite robust:

 

 

 

 

Lastly, I ground down the back of the magazine between the feed lips so that it would accept my MagLULA Colt 9mm loader (loading these magazines with thumbs SUCKS):

 

 

This is what it looked like before I gave it a shot of OD Green KG GunKote:

 

 

And in my 10.5" 9mm SBR:

 

 

The FrankenMagazine Gods must be smiling on me because this magazine runs very reliably. To be safe, I squirt a generous amount of graphite powder into the tube while loading it (one puff for each 10 rounds), but this may be unnecessary.

 

Any questions, post 'em here. 

Edited February 25, 2018 by StealthyBlagga

[1981Shooter]

I don't even have anything that runs Colt mags, but that's a great write up!

[tyman1876]

That’s super cool. I’m impressed you got it to run just right on the first try. Nice little SBR as well

[1981Shooter]

Reminded me of this pic 

[troupe]

great job with the pics and info.

[BartCarter]

The copper backing was a great idea.

[RaylanGivens]

Sweet!  Great writeup...

[RevolverJockey]

Another trick that works well is to replace the springs with +power ones (one stock length and one with 6 coils clipped off) and leave the 2nd follower in place as well as the baseplate retainer. You lose 1 or 2 rounds but you don’t have to attach the springs which could come undone or loss temper and you can field repair with your short stick mags if you are away from home. With mine I get 51 (50) reloadable and it runs and runs and runs. 

 

 

[StealthyBlagga]

On 2/25/2018 at 9:11 AM, 1981Shooter said:

Reminded me of this pic 

 

Funny you should mention that... one of my earlier creations:

 

[bwikel]

4 minutes ago, StealthyBlagga said:

 

Funny you should mention that... one of my earlier creations:

 

Man you really hate reloading huh. 

[bladewurk]

no mods to the followers guys?   No nosedive jams??  I saw a guy this past Sat with a very nicely tigged  55 rder, and he fabbed the follower from an STI follower.

 

 

[RevolverJockey]

I am running a stock metalform follower - actually two of them. Not a single problem.

[Shorty4087]

Nice job explaining your process, including pics, and I also soldered my springs together utilizing the small brass tubing.

[Garrett]

Nice! 

 

Now take that 60-round mag and Taccom a 40-rounder to it. 

 

 

[Bdh821]

Welded mine up. I need to figure out the best way to make the mag springs work now. 

[BartCarter]

Nice weld.  No filler?  Purge?

[RevolverJockey]

I know I sound like a broken record but using stock springs with dual followers is an easy way to do and I am running the same springs I have had for years. I must have 10k rounds through this mag and have never had a malfunction. Even in full auto. 

[Bdh821]

Thanks! No filler. Square grove butt joint with argon purge. I used to be a tig welder for work, so that part wasn't an issue. I wish I did a tiny bit more purge pressure as the corners sunk in a tiny bit and needed some internal filing. For guts, I stuffed the 2 springs, 2 followers, and 2 base plates in it. I manually cycled it thru the gun it worked. I got 44 in before my fingers hurt.  I need the maglula thing. 

[RevolverJockey]

Unless your second spring was a 20, take a lot 10 coils off and you should get closer to 50. The UPLULA is the only way to go with these mags. 

[Bdh821]

The second mag is a 20. 

[RevolverJockey]

If you can’t I can measure mine and measure the springs but I get 51/50 reloadable. 

[Bdh821]

I bought the + power spring for the +10 baseplate from Taylor freelance. Seems to work altho haven't live fired with it yet 

[L9X25]

Taccom sells replacement springs for their 58-60 round extensions.  I purchased several of those and they can be cut down to whatever is needed.  I use one in my 33+33 splice mag and it works fine with ~65 and eliminates the need to solder together the springs.