STI/Grams Premature Slide Lock

[Maksim]

Hey guys...

question, I am sorry if this was covered before.

At a local match, just switched to shooting L10 to practice for nationals. After 3 stages, I thought someone was messing with me (pulled one round out) when my gun went into slide lock when it should not of... on the last stage I noticed the mag and it still had one round left in it.

Shooting Limited the past year or so, I seldom had to run the gun dry, and when I did, I would of use my SVI mags which run flawlessly.

So, what would cause this?

The mag is a 140mm STI tube, where I replaced the guts with a Grams Spring and Follower, dawson basepad.

I do not know if this happened before as I did not pay attention, just that mag fed reliably. I would of reload before the mag went empty.

[Jonathan Taliani]

Have your followers or slide stop been modified? This is a fairly common issue which is why many people modify their slide stops and or followers to not lockback at all. This prevents a premature lockback when a round is left in the mag.

[AirBorne]

Not sure if this helps but here goes, when I replaced the spring and follower in my Limited STI mags with Gram springs, followers, had to sand down the left front and about half the side part of the follower to keep it from locking back with one round left in the mag. Now it will run dry and not lock back,tho I do try to avoid running dry by counting my shots. Btw I posted a similiar question about this same product a few weeks back and folks were quick to point out how to correct it. Hope this helps.

[Maksim]

Have your followers or slide stop been modified? This is a fairly common issue which is why many people modify their slide stops and or followers to not lockback at all. This prevents a premature lockback when a round is left in the mag.

Neither have been modified.

SVI locks back on regular mags with regular followers, will not lock back on the SVI Red (high cap) follower. Locks back on stock mags with the big black follower.

Grams Follower/Spring.... locks back with 1 round still in the mag.

[yoshidaex]

What bullet profile are you using?

[Maksim]

Extreme Plated Hallow point... basically an fmj round nose 40, with a hollow point, no feeding issues at all.

[xdnok]

The Grams follower needs to be modified to work correctly if you want the slide to lock back. I have to remove a small amount of material at the front edge of the follower that contacts the slide stop to get reliable lock back.

[rooster mcbee]

I use 3 old style SV mags that I just put Grams springs and followers in. They all lock open with one round left now. I haven't tried to modify them. They work 100% now except for that. I should mention that they are .38 Supers.

[RustedFrog]

I just put Grams followers in my STI Executive .40 mags and was having the same problem. I used a medium file and took a little off the left front of the follower and the smoothed it up and they all work great now. It just took some time of try and retry.

[40S&W]

You need to modify the follower as mentioned earlier. Check You Tube, I'm sure there is a video on how to do it. I modified all my followers on both single & double stack mags so that the slide never locks back. It only takes about 2 minutes to do a mag.