My FFL uses a dull (butter) knife to pry the plate off from the back. I can't do that myself.
I bought a small, 2" C-clamp to use. I put it on the magazine just above the middle of the floor plate and screw it down to compress the magazine body. Before you go very far depress the button in the middle of the plate or else it won't budge under the pressure. When the tabs that hold the floor plate in are disengaged, slide the plate off. You can then take the C-clamp off because the extension plate will slide on easily.
After the first time or two it is much easier to do.
I use a punch, and pretty much follow the standard instructions.
The key, is not being afraid to use enough force to get the base plate going. Unlike, for example Walther P99 magazines, where it is only necessary to slightly depress the button before the base plate slides off, with Glocks, you have to jam the punch in, and pry the base plate forward, while leveraging the punch agains the mag body.
If you are ever at MRA, I can take a stab at getting the base plate off.
Listen, just box up all your .40 mags and extensions, send them to me, along with a small donation (small, unmarked bills preferred) and I'll set them up for you. I will then test-fire them and watch them over the course of a year or two to make sure that they work. I will send them back after I am sure that they will last.
Listen, just box up all your .40 mags and extensions, send them to me, along with a small donation (small, unmarked bills preferred) and I'll set them up for you. I will then test-fire them and watch them over the course of a year or two to make sure that they work. I will send them back after I am sure that they will last.
I push in the mag tabs while holding the edge of the base plate against a desk, and applying pressure to make the base plate slide off. I position it against something so that the spring doesn't go shooting out of the mag.