T3 mag mod
I picked up a T3 lite stainless 223 last year. I too found the mag a little short. I managed to open it up without much difficulty at all.
I too thought I would have to drill the pins out and permenantly glue back together after. I really didn't want to do that so I managed to remove the bottom without any damage.
What I used was a bench vice that I keep near my gun table. I laid a cloth in the jaws so not to mar the mag. I placed the mag in the vice only deep enough to grab the bottom right at the seam line. Then gently compress with the vice while pulling up on the upper part. POP! it'll came right out. I know the bottom looks very solid but it did compress just enough to let the pins slide out of the slots, with some muscle mind you.
It's been a while so I'm not absolutely sure but I think I pulled the follower and spring out first and then used a large wide, taped, screwdriver and inserted it into the mag down to just above the seam line, gently twisted it at the same time. (come to think of it, I belive I was planning to do that but didn't have to)
I then dremeled out the back behind the follower but I didn't dremel out the entire back plate so it was flush with mag walls. I left a very slight ridge. I used this ridge to hold the new backer I made afterward. I didn't remove any material from the bottom of the mag so the spring would not slide back.
The material at the top of the mag was removed, very carfully with an exacto knife. I was trying to use a 69 gr smk so I only removed about 0.100 which put it just behind the ridge of the old removed backer I mentioned earlier.
For a new backer I used a 1/8 piece of aluminum. I cut it to the exact width of the mag and bent it in a "C" shape. Well, you know with sharper corners. The height was the exact distance from the top of the mag to the material on the bottom piece. You'll see what I mean when you pull it apart. The ends of the aluminum were cut to reach the rear of the mag exactly so it wouldn't slide back. I simply pushed the whole thing up from the bottom in behind that ridge I left behind. So now it can't move in any direction. I was planning on glueing it in but with such a tight fit I didn't have to.
By modding it like this I can always go back in and re-adjust later if i have to.
I hope this helps. If need be, I can see if I can get a few pics up of my mag.
Paul