Magazines hanging in STI grip

[nYdGeo]

Good day! I am new to the 2011 pistol format, the pistol in this case being an STI Competitor in .38-Super. It was bought, shot for a few hundred rounds and then sat in a safe for the next 6-years or so, and now I've purchased it from the original owner. I had a brilliant, local smith lighten the slide from 12.5oz to 9.75oz bare. Next, I'll have him install an extended ejector as amazingly enough this pistol did not come with one installed. I replaced the 17lb mainspring with an ISMI 15lb, and using a Wolf 9lb variable recoil spring, I'm reasonably happy with it.

My problem is this: starting with the last match that I shot, every one of my magazines is hanging in the grip. I along with others have examined the pistol and determined that the issue is that the magazines are rubbing the inside of the grip front & back. Trying to hang on to Glock pistols which I love but find rather slippery, I developed a bad habit of using far too tight a grip. Also, I squeeze only front to back, applying next to no pressure on either side of the grip. I am told that over time I have reshaped the grip so that where my middle and ring fingers squeeze the grip it is now physically shorter front to back.

First, if this is even possible I am astounded. It never happened to any of my Glock pistols and I have over 50K rds through a couple of those as compared to less than 1K rds through the STI.

Anyway, I am told that I can shorten my mags slightly in a vise to work around this; I was also told that this is often part of magazine tuning. So, here are some numbers. My factory STI tubes are wider in the front than they are towards the rear. The front of the mags measures right at 0.933" wide, the rear slightly smaller at 0.928" wide. The middle section is narrower still, but I am unable to get a measurement. Measured front-to-back, they are also slightly inconsistent, but the largest measurement I got is 1.380".

I have access to a huge, machinist's vise along with the assistance of a machinist/gunsmith. I was wondering if I might coax someone with a nice, 'tuned' STI magazine tube to measure the tube front-to-back and provide me with a dimension to shoot for. I would appreciate that very much as I'd like to use the pistol this weekend.

Also, can anyone tell me if the magazine tube should be wider towards the front than towards the rear and narrower still in the middle? None of the mags for any of my other pistols are made this way, but maybe it is normal for STI mags.

Thank you in advance for any constructive information and/or assistance.

[RussB]

Are you sure the mags aren't dragging on the trigger bow?

Perhaps the grip screws?

Disconnector sticking into the magwell?

Loaded, my 7 140mm mags measure 1.380" X .950" +-.005"

[Two Delta]

I say if the magazines are working reliably then check the grip.Check everything mentioned above.Make sure nothing is rubbing the magazine.I've had a brand new grip out of the package that the mags fit into and dropped freely from bind up once installed onto the frame.Possibly from over tightening the grip screws but once the grip is removed again from the frame then the mags still bind.You may remove the grip and see if they are binding.If they are still binding with the grip removed from the gun then I have removed some material from the inside of the grip.I used a wooden dowel and some 320 grip sandpaper.Do not take too much especially in the corners where the plastic is thinner.Take a little bit all around then check that all your mags drop free.When they all drop free I take some 600 grit wet and dry and a small amount of FP-10 and smooth everything out.Good luck.

[AlamoShooter]

When I am not injured my hand will squeeze the grip hard enough so the that the mag holds up until I loosen my grip with the right hand. You may have to let - up on the grip during the reload

[RussB]

nYdGeo,

Has the grip on your gun been re-textured and/or relieved under the trigger guard?

just curious

[kgunz11]

Take the spring and follower out of the magazine and try it. Hold the grip loosely and see if they drop free. You're mags are a little fat front to back by .010, but that alone should not make them stick.

[nYdGeo]

Thank you for all of the questions, suggestions and information. I'll check the things suggested.

A few answers: I can let go of the grip completely and they still won't fall, empty or loaded. Haven't had any grip work down; fortunately it fits my hand nicely as it is. All of my mags work great, and I'd rather not modify them unless I have to.

One curious recollection: The last time I shot this pistol before observing this issue was at an indoor range. I was there for another purpose, but decided to fire a few rounds through the STI just because its fun. While doing so I located a particular round that, sparing all of the details, got loaded into a very old case that I had retired but accidentally got mixed into this batch when I loaded it. I knew that one brass fell in there...anyway, I located that bad round when I had a case blowout. Got some blast on my hand, felt a bit on my face, but didn't blow-out the mag, the bad brass ejected, the next round chambered, bullet went through the target, etc.

I unloaded the pistol, field stripped it, found no debris or visible damage that I could identify, reassembled it, put the same magazine in it, cycled the slide, and shot the rest of the mag before putting it away.

This case blow-out might have altered something that I am unable to identify and is causing the problem. I'll examine it again, and if I cannot find the problem I'll bring it to my gunsmith. Again, thank you all for the input. If anyone has any suggestions as to what that event may have changed, bent, or otherwise altered, I am all ears!

DVC

[G-ManBart]

It's pretty common to have to remove some material on the inside of STI grips to get mags dropping free (with zero grip pressure). This is more common with SV mags than STI mags, but can happen with either. I simply use a combination of files and dremel tool with a sanding wheel and simply make the room necessary. I've done that with a number of guns and it has never caused any problems of any kind. R,

[RussB]

Hmm, I wonder if after the case blow-out, if a little piece of brass didn't get imbedded into the plastic magwell?