Spacers for 9mm in STI mags?

[Rob Tompkins]

I'm new to Open and the STI 2011 platform. I just bought a used gun in 9mm major and woder if mags need to have the "spacer" I see listed all over the place.

I will be reloading and expect to be loading long ~1.17+" OAL.

Thoughts?

Rob

Edited May 20, 2010 by Rob Tompkins

[MikeFoley]

STI mags run better with the spacers. SV mags do not require the spacers. Both mags like 1.155 to 1.165 ammo in my gun. You can get metal spacers, like the HSMITH or Joey Hardy, I recommend getting 170mm and cutting them to fit your basepads. If you use flat basepads, the 140mm will be fine. You can also get plastic spacers like the Arredondo or STI. They come ready to cut or break for preset lengths. The price difference is negligible. Some guys attach the spacers with different adhesive methods. I leave mine loose. They work great. The rattling only occurs when they are unloaded.

[Pat Miles]

If the mags you buy are SVI mags the answer is no. The SVI mag tubes have a centered wide rib that keep the rounds aligned in the staggered formation inside the tube. The STI tubes have two thin vertical ribs that accomplish the same thing. The problem arises when a 9mm round is put into the mag. The round is too short for the front rib to keep it aligned. The spacer in the rear of the tube forces the round forward (duh)so it engages the front rib and allows it to do it's job. There are folks who can "tune" an STI mag body so the spacer is not needed. I am sure they will chime in here at some point.

CYa,

Pat

[mildot1]

You will either have to alter your followers or get 9mm followers when you add the spacers.

FWIW

Mildot

[Jaxshooter]

I have few STI mags I am using for 9 mm and have been using Arredondo spacers and have had very good luck with them. They have the side flap that folds over and prevents the bullets from sliding off of the follower when it gets past the side ribs at the bottom of the magazine. I have one 170 mm STI mag that holds 30 rounds. I do not glue them in.

[TMC]

Have you tried it without spacers? I have three 9mm S_I guns and none need spacers in the mags with any length ammo. I have a larger number of both STI and SV tubes with a random set of followers and springs and it doesn't seem to make a differnce. I say try it first, if you don't them its one less thing to deal with.

[Rob Tompkins]

Have you tried it without spacers? I have three 9mm S_I guns and none need spacers in the mags with any length ammo. I have a larger number of both STI and SV tubes with a random set of followers and springs and it doesn't seem to make a differnce. I say try it first, if you don't them its one less thing to deal with.

Short answer no, not yet. But I'm shopping for more mags so I'm seeking enlightnement without having to buy stuff twice.

Rob

[Rob Tompkins]

Ok, I just built / rebuilt 3 ea 140mm and 1 ea 170mm mag's using Grams 9mm followers & springs, Dawson +1 extensions, and 9mm spacers all in plain stock STI tubes. Based in the description of the follower / spring kits on the ShootersConnection web page I got 13 coil springs for all the mags, including the 140mm tubes. The instructions that came with the follower / spring kits indicate they were only for 145mm and longer mags. With all 13 coils I could just load 22 rnds in the 140mm tubes so I cut off 1 coil and now the 22rnd has some room but I can't get in a 23rd round. The 170mm tube will hold 28 rnds ok but not 29.

Does this sound like a reasonable out come?

Thanks,

Rob

[G-ManBart]

Ok, I just built / rebuilt 3 ea 140mm and 1 ea 170mm mag's using Grams 9mm followers & springs, Dawson +1 extensions, and 9mm spacers all in plain stock STI tubes. Based in the description of the follower / spring kits on the ShootersConnection web page I got 13 coil springs for all the mags, including the 140mm tubes. The instructions that came with the follower / spring kits indicate they were only for 145mm and longer mags. With all 13 coils I could just load 22 rnds in the 140mm tubes so I cut off 1 coil and now the 22rnd has some room but I can't get in a 23rd round. The 170mm tube will hold 28 rnds ok but not 29.

Does this sound like a reasonable out come?

Thanks,

Rob

Yep, that sounds about right. I wouldn't have cut the coil off the short sticks...with a little use you'd have 22 that would be reloadable. Any more than that in the short stick, or more than 28 in the big stick and you start to have to worry about followers rolling (down at the bottom where the ribs end).

I shoot mostly .38SC, but picked up a used 9 Major Open gun a while back and it runs even factory WWB out of STI tubes with no spacers...was pretty surprised, but it works. R,