I have seen and handled a Glock with an external safety and here is the only problem.
SAFETY INSTALLATION JIG - Holds your Glock frame securely and has two, machined slots that correspond with the cut you’ll have to make to install Cominolli’s Manual Thumb Safety, shown above. Slot marked “SM” is for 9mm, .40 S&W, and .357 SIG; slot marked “LG” is for .45 ACP and 10mm. Requires the use of a 3/32" End Mil, listed below, and a high-speed rotary tool (listed elsewhere) to properly make the cut. Delrin® guide makes it easy to cut the correct angle
The cuts this guy made unfortunately look like dookie, but it worked as advertised. If your not a "tool guy" and you don't have a steady hand, don't do it yourself.
Others are mentioning getting an XD but honestly the grip angle and triggers are different than the Glock, and a grip safety is not the same as a manual safety switch.
SAFETY INSTALLATION JIG - Holds your Glock frame securely and has two, machined slots that correspond with the cut you’ll have to make to install Cominolli’s Manual Thumb Safety, shown above. Slot marked “SM” is for 9mm, .40 S&W, and .357 SIG; slot marked “LG” is for .45 ACP and 10mm. Requires the use of a 3/32" End Mil, listed below, and a high-speed rotary tool (listed elsewhere) to properly make the cut. Delrin® guide makes it easy to cut the correct angle
The cuts this guy made unfortunately look like dookie, but it worked as advertised. If your not a "tool guy" and you don't have a steady hand, don't do it yourself.
Others are mentioning getting an XD but honestly the grip angle and triggers are different than the Glock, and a grip safety is not the same as a manual safety switch.