Premature Lockulation

[BangSwitch]

I'm still very new to the STI platform (~2 months in now)  and learning more every day.  I understand that lots of 2011 shooters have problems with the slide locking back with a single round left in the magazine.  I've discovered this phenomena in my own gun and just about every magazine.  I recently ditched the factory springs/followers in all five of my "gen 2" STI magazines.  I use Grams springs/followers now.  

 

When I ask other shooters about this, they just tell me to dremmel the corner off my followers and learn to count shots.  ....that is a solution, but I sure would like to figure out a way to get the slide lock function to operate "most" of the time.  From what I've read, 100% operation is damn near impossible.

 

So in the interests of understanding the problem I popped my slide off and loaded some snap caps and watched what was happening.  

 

It seems that the follower is "canted" in the mag tube and doesn't sit level.  The left side of the follower rides higher than the right and is hitting the slide stop first.  It's pretty easy to see when I pull the spring/follower out too.  If the follower rode up the feed lips dead level, the slide stop wouldn't prematurely engage.  

 

I thought about removing 1mm of material from the corner of the follower that hits the slide stop. 

Bending the crap out of the spring looks like an option too, but common sense told me to stop.

 

What steps do you guys recommend if I want to try and retain the slide lock function?

 

 

 

[BangSwitch]

...and another picture illustrating the way that the follower is aligned in the mag tube.

It's easy to see how much higher left side is sitting and why it prematurely hits the slide stop.

[glassblower]

 Mags that don’t go to slide lock and are 100% reliable requires “tuning”. Such as spacing the feed lips according to the caliber used in the mag. Polishing up the inside of the mags and cutting the follower are also part of it. There are a number of how tos in the forum. You can also get a tuning kit from Dawson Precision. Bending your mag springs isn’t typically part of mag tuning.

[Mountbkr]

Go watch the Atlas Gun Works videos on Youtube, he has one that covers this

[rowdyb]

totally normal. making mags work is a process. nothing will be straight and square and level like maybe you've experienced in non-2011 platforms and magazines. the width of the follower relative to the mag body interior dimension coupled with the change in dimension as the mag narrows from bottom to top yields the cant/twist you see in the spring and follower. One reason why people are very particular about not messing with a spring and follower combo they find that works for them.

 

most of us use followers, or modify the follower, such that it absolutely cannot contact the slide stop lever.

[mlmiller1]

Just to add if you are at slide lock & reload a new mag vigorously, bad things can happen.  Broken ejectors...&.... wedged magazines nearly impossible to remove are 2 possibilities.   Thats why most of us disable the followers.

Edited November 20, 2017 by mlmiller1

[Powder Finger]

these guns have been around since the early 90's, there is a reason people tell you to deactivate the slide stop.

[rowdyb]

OK, I just reread your post. You wwaanntt to retain the function of the empty mag locking the slide open, 100% of the time? Are you shooting IDPA or?

 

You're going to, just my opinion, need to change followers and also work on your slide stop lever itself if you want a (what length tube?) in (what caliber?) to do this.

Edited November 21, 2017 by rowdyb

[BangSwitch]

1 hour ago, rowdyb said:

OK, I just reread your post. You wwaanntt to retain the function of the empty mag locking the slide open, 100% of the time? Are you shooting IDPA or?

 

You're going to, just my opinion, need to change followers and also work on your slide stop lever itself if you want a (what length tube?) in (what caliber?) to do this.

I am not shooting IDPA, I'm shooting USPSA Limited minor (9mm naturally)  ....I know slide lock reloads are a "bad thing" in USPSA.  Coming from a 9mm single stack gun, I'm used to having a functioning slide lock. 

 

My magazines are 140mm STI "gen 2" stainless w/ Grams FKS-11 spring/follower kits. 

 

BTW - I've got one of those mag compression pliers/tools on order.  I already have a micrometer.  I'm planning to donate one mag tube to science and see if I can tweak one into submission.

[36873687]

With new gen 2 mags had this problem also. Just like u said take some more off the follower. We’re it contacts the slide stop. Running same grams guts. I️ heard grams wasn’t going to change anything for sti gen 2 mags. It’s easy fix though

[RJH]

9 hours ago, BangSwitch said:

 I'm shooting USPSA Limited minor (9mm naturally)  ....I know slide lock reloads are a "bad thing" in USPSA.  Coming from a 9mm single stack gun, I'm used to having a functioning slide lock. 

 

 

While I get what you are saying, the main issue is not that slide lock reloads are a "bad thing" in that it is bad in stage planning (although it is).  The issue is the very real possibility of broken parts due to the over insertion of the mags while the gun is in slide lock.  With your slide off of the gun insert a mag and look at how close it comes to the ejector.  If you push up on the mag does it hit? What about when you slam in a full one?  Single stack guns are less apt to have this issue because many of the mags have bases that hit the magwell or grip before the top of the mag hits thee ejector, although it can be a problem there too.  Good luck

[BangSwitch]

1 minute ago, RJH said:

The issue is the very real possibility of broken parts due to the over insertion of the mags while the gun is in slide lock.  With your slide off of the gun insert a mag and look at how close it comes to the ejector.  If you push up on the mag does it hit? What about when you slam in a full one?

That's actually one of the first things that I noticed about my STI.  I found that a couple of my mags had scratches from impacting the ejector.  I took my gun to a local gunsmith who competes in USPSA and services many of the top USPSA shooters in the area.  He removed my ejector and reinstalled/repinned it correctly.  Now it takes real caveman moves to get a mag to contact the ejector.