And of course, this is the back of the instructions; click to enlarge. Do note that the "intuitive" use for this device would be incorrect - read the instructions, and it shows you the intended use for it. It's meant to be used against a surface, not as a gripped device as I describe under "Using It Wrong".
The Handi-Racker is not designed to ride on the gun's front sight, but it may with some pistols, particularly if you're using a larger version with a smaller pistol. The slot you see in the middle is meant to avoid contact between the Handi-Racker and your front sight. The bottleneck there is the intended load bearing surface for your slide, and the narrower bit beyond is where your barrel is meant to extend as your slide goes back. The widest part is where you place the front of your slide before you use the Handi-Racker.
To the right, you'll see a picture of me doing it wrong. Gun owners, myself included, frequently don't read manuals. We just start using things, and do what seems logical. I try to take that approach first in my reviews to get the 'cold' impression on things, then come back to find out the "right" way to use a product. My first guess at how to use the Handi-Racker was to grip it and use it to rack the slide of my weapon. It did work, but I noticed that the edges were slippery and tended to pull past my hand. However, some skateboard tape on the edges would do a magnificant job of keeping it from sliding. For someone who doesn't want to need a flat surface to rack the slide on, that might be a useful modification. But for typical range and home use, it's much easier to just use it the way it was intended.
To the left, you'll see the actual intended use of the Handi-Racker. It's meant to be used in order to rack the slide against a hard surface. The reason that it's so long is to give your barrel enough room to clear the end. Most guns are fine with this, although on a few longer-barreled guns you'll need to place the handi-racker on the edge of a table so that the barrel can clear the end.
My Sig comes in for a "landing". Note that the "bottleneck" has the narrow end facing in the direction of the barrel. That's because the narrower part is for the barrel to stick through.
Showing correct orientation on the table: you point the gun straight down, and support the handi-racker on the other side so that it remains square. It is of course possible to mount the handi-racker to another surface if you only have one usable hand. If you have an outdoors shooting bench (or have a setup on your porch, for the more rural areas), you might consider permanently attaching one to your table if that's the case.
Now I'm pushing down on the frame of my Para P-14, and you'll see that it's pushed the slide back. My wife occasionally has trouble racking the slide on this one, and the Handi-Racker does make it easy.
Now pull the gun up and out of the device, and a round will be loaded into the chamber.
A close-up of the barrel and guide rod protruding through the channel on the handi-racker. You'll notice that the barrel is contacting the surface of the table here. That's easy to fix by positioning the Handi-Racker on the edge of the table so that the barrel doesn't make contact. Also, even though it did make contact, I still had enough travel in the slide for it to chamber a round.
My Sig, with the slide locked open, showing what most semi-automatic pistols will look like during use of the Handi-Racker. Notice that the barrel doesn't reach the end of the channel.
-- Photos by CraigJohnson - 19 Jan 2013