The guy who taught my ccw class was a Glock armorer and said that a plug for the handle was a terrible idea because there is an exhaust port to blow out debris. I can see the mechanics through the handle on my 26 but is this true or anyone else have heard this or refute it?
It is there so you can clear a type 3 malfunction on the glock. With most other firearms, you will have already tried the "tap, rack-n-roll" then determined that didn't clear the stoppage. You would then lock the slide back (pretty hard to do when the slide is already that far open) hit the mag release, while pulling the magazine out of the gun and throwing it on the ground. Then you would rack the slide 3 times quickly and with some force, let the slide close, put in a fresh magazine, rack the slide to chamber a round, and fire.
With a Glock, the first (and most difficult task of locking the slide back) is eliminated. You would simply put your thumb into the hole in the grip, finger on the front of the mag, press the mag release, and strip the mag. The offending round will drop out of the gun. Then rack the slide 3 times, insert a fresh mag, rack again and fire.
It may not seem like a big difference, but while your hands are in the firing position, to move them to hit the slide release, and hold it up firmly while pulling the slide back that 1/8" is much harder than you might think. If you were locking the slide back with the slide closed, your momentum will carry the slide all the way to the rear. With the slide almost already fully open, the spring is compressed, and that last little bit is a *****.
So, by putting in a plug, you eliminate your ability to put your thumb into that area to grip the mag, and therefore eliminate your ability to quickly and accurately clear a type 3 stoppage.
I personally have a plug with a lanyard loop, Why? Cause I all so have a +4 extinction on my mag and have enough room on that to grab a rip the mag.