To see what the "C" is all about when it comes to Glocks please read Glock 17C, si?

The Glock 24C is the .40 S&W version of the Glock 17L*. It also features a long slide and barrel and is primarily a competition pistol. The extended slide and barrel make it unwieldy as a concealed carry sidearm.

*The Glock 17L was for a time also provided with built in compensators but when it proved to significantly weaken the intergrity of the slide was since discontinued.