STI .45 Magazine Capacity

[parsonm1]

I have read about this here before, but couldn't find anything specific using the search function.

Here's what I have... I am running an STI framed pistol in 45 acp. I have 5 140mm mags. I can only get 12 rounds in each of them without using a brake press to squeeze in 13-15.

I am using standard mags and components: 140mm tube, STI follower, 140mm spring, 170mm basepad.

How do I increase the standard capacity? I have them sitting now with 12 to set the spring. Would it help to cut a coil or two from the spring? Trim the follower? Beat it with a hammer?

Help!!!!

Thanks

[XRe]

STI says 14-ish. Contact Beven Grams??

[TDean]

What spring is it?

Count the coils starting from the top. I'm running 10.5coils in my 140mm .40STI tubes. If you have a longer basepad on there to increase the OAL to 170, you may need a couple more coils than 10.5. Maybe 13.5?

[parsonm1]

If I count correctly, the spring is an 11 coil spring (11.5 actually). The base pad is the standard basepad that comes in multi-colored variety. Doesn't add any rounds but makes 140mm.

Thanks

[diehli]

Are you sure they're .45 tubes and not .40 tubes?

[Chuck D]

My STI tubes hold 14 with a flush factory base pad.

I get 1 extra round with a Dawson pad.

Both set-ups use a factory STI 140mm mag spring.

[parsonm1]

My STI tubes hold 14 with a flush factory base pad.

I get 1 extra round with a Dawson pad.

Both set-ups use a factory STI 140mm mag spring.

<{POST_SNAPBACK}>

Wow! I would be OK with that. The tubes are 45 tubes (4 shallow grooves) and the springs and followers are factory (I built the mags from factory parts since complete mags were sold out at my usual supply).

Chuck, how many coils on your spring and has the follower been modified? (If it isn't too much trouble to check).

Thanks

[Chuck D]

No follower modifications...will count the springs when I get home and let you know.

Never a bother !

[Chuck D]

Just counted 'em for you.

11 coils including the partial coil at the bottom of the spring.

Never clipped any off...just installed them right out of the STI package.

Hope this helps.

[David Olhasso]

You should easily be able to get 15+1 in an STI 45. I had one many years ago and I think that I could start a stage with a 16 round mag that I had to pound into the gun.

[TeamGE]

In the old days, when the whole STI/Chip McCormick frame started, the original .45 mag tube, with a pad that extended the mag to 140mm, would hold 16 rounds, no problem. Todays mag tubes are made on different stamping dies, and will normally hold 14 to 15 rounds, tightly. I can tune most mags to hold 16, but there is no getting around how tight it is going to be. It is just the nature of the beast, and I have done all I can do with this caliber and the mag tubes we get today.

[TDean]

I'm getting 17+1 in may Para 45 mags with dawson pad.