There are many reasons why you would want or need to draw your defensive handgun with your support hand. It could be that your gun hand or arm is injured, or that you are defending against a close attacker with your stronger arm.
Regardless of the reason, knowing how to draw your handgun with your support hand is a good skill to have. Of course, a lot of it has to do with where your gun is located, but most carry methods can be accessed with either hand with some practice, which should always begin with an unloaded or inert gun.
Sheriff Jim Wilson recently explained two methods for drawing a handgun with the support hand, and the issues that should be considered for this to be possible. Both of these, though, were explained from the strong-side position, which is not used by everyone. Personally, I believe the best way to provide a firearm for the support hand is a second firearm.
Sure, I have trained reaching my Kimber with my support hand, but regardless of how much I practice, it just doesn’t feel smooth, and I can see this being a problem in a real situation. For this reason, I prefer a second handgun located in a position that is more easily accessible with the support hand, such as in the pocket or on the ankle. Beyond the better access to a handgun if the strong arm is disabled or otherwise engaged, a second handgun provides additional firepower and can be handed off to a partner if needed.
