No need to get a new spring...Here's the mod that I had done to a few of the 15-rounders that I had found (cause there was a shortage of full mags).
15-round mag into 24-round mag
I got fed up with not being able to find any 22-round mags for my PK. So I purchased a 15-round mag at the range the other day. They had about 9 of them there. After reviewing the mag, I came up with an idea. I modded it to take 24 rounds. That's right, 24 rounds!
DISCLAIMER. Check you own State's law before proceeding. Mod at your own risk. I'm not responsible for your action or decision.
One (1) 15-round mag.
The GSG tool that came with your riffle/pistol.
A 9/64 drill bit and an electric drill.
A Dremel cutting bit that looks like a drill bit. And a Dremel. If you don't have this, might be able to work with drill bit.
I can't find my camera cord, so I'll post picts tomorrow.
Here are the steps:
1) Take off the 2 screws on the top of the mag. And the 2 screws on the bottom of the mag's base. And lastly, the hex bolt on the follower.
2) Carefully pry the two halves apart. The lower spring base, not the cap, is slightly epoxy to the stopper piece and also to one of the mag's side.
3) Once apart, you can pry off one of the stopper that's on the rail of the mag.
4) Use the 9/64 drill bit to drill out the other pin of the stopper to the lower spring base. You'll only need to drill out one of the two pins, since only one is epoxy to the lower spring base. Use the drill bit to punch out the other pin to the base. Now take off the stopper on that rail, and the lower spring base.
5) The epoxy might have spilled onto the rail of the mag, so this is where the Dremel comes in. Just use it to smooth out the rail so the follower will slide smoothly up and down the mag. Make sure you clean out any plastic pieces that might come from the Dremeling.
6) Apply some grease, if need to, and assemble the mag back together. Leave the lower spring base out, and use use the base cap. There are two small posts on the cap to help keep the spring in place.
7) Now load up 24 rounds of .22LR. Have fun!!!