9MAJOR in STI Mags without spacers

[fmj3]

It was told to me by Beven that although sometimes an STI 9mm/38 super mag may run reliably for some with 9mm ammo, the STI 9mm/38 super tubes are just not designed to run reliably with 9mm ammo, without a spacer that is. The location of the front control rib is what makes the problem appear. The top of the case could get stuck along the rear beveled edge of the front control rib as the rounds are feeding up through the mag. The spacer moves the rounds forward enough so as this does not happen, keeps the side of the case on the "high" side of the front control rib inside the tube.

I know, there are some to many, as listed above, that have had no problems without spacers, just passing along what the mag master explained to me.

I'm sure he knows more than most about it but it seems a long round would overcome that. I guess I'll get my hands on a mag or two and try it out.

I didn't for me. It's the case length not the OAL that is the issue. They would start jamming side by side instead of stacking if the case mouth didn't reach the second rib in my case. The full width rib like SVI or MBX alleviates that issue - at a cost.

[BrianATL]

Interesting topic. I recently found out that loose spacers where causing issues for me as well. The mags were STI 140's with grams springs & followers, TTI 7G basepads, and TTI aluminum 140 spacer. The spacer would set just low enough to allow the top round to sit on top of the spacer making the mags non-reloadable . Ended up using RTV to attach the spacer to the tube.

So your issue is the spacer is not the long enough since your mag basepad combination is longer than 140mm??

[Sarge]

Interesting topic. I recently found out that loose spacers where causing issues for me as well. The mags were STI 140's with grams springs & followers, TTI 7G basepads, and TTI aluminum 140 spacer. The spacer would set just low enough to allow the top round to sit on top of the spacer making the mags non-reloadable . Ended up using RTV to attach the spacer to the tube.

So your issue is the spacer is not the long enough since your mag basepad combination is longer than 140mm??

My spacers are cut the length of the tube. Once you put a basepad on they slide down.

[gng4life]

Sarge, what basepads are you using? Is the Bolens/TTI style?

[Aircooled6racer]

Hello: I just buy the steel 170mm shims from Shooters Connection and cut them to length for the shorter mags. I use Dawson or Grams base pads. I use SVI old style mags personally most of the time. The Dawson follower does not roll over like some of the others in a STI tube. It also does a better job of controlling the rounds as they come up. You can still get 29 rounds in there also. Thanks, Eric

[Sarge]

Sarge, what basepads are you using? Is the Bolens/TTI style?

Yes

[cecil]

I used 3M - 2 sided tape... I bought it at Auto Zone..

[gng4life]

Yeah, that would make sense, the spacer can slip down due to the type of pad. If you use Grams or Dawsons, you can make the spacer longer and fit the pad, keep it at the right height. I have a Grams on the one mag with the spacer.

Did you ever find out what tape those guys were using?

[Sarge]

Cecil replied but there are several types of the stuff. I would think it has to be very thin or else you really end up with a short round to make it fit. I like about 1.168 or so. I have used some of the 3M outdoor tape and man does it stick! but it is very thick for this application.

[Hammar]

I do the same as Eric; I buy the steel 170's and cut them to size in the 140's. Mine have worked with the Dawson and TTI base pads with the grams guts.

[nelly]

Hi All, I was having a spacer issue with my STI 9mm 140's & 170's, spoke with Beven and he suggested I use "Pro Seal" Clear RTV Silicone Adhesive and Sealant. Ran a couple of thin beads of this on the back of the spacers(STI Plastic Stock) and they haven't moved in over a year.I clean the tubes normally with a long brush and wipe them out with a piece of Cotton T-Shirt. Beven Knows what he's talking about. This RTV Silicone Adhesive is available at Northern tool or probably any good hardware store. I got mine at Northern Tool for a couple of bucks.