There is a chance that we might be injured before we know about the threat. If your dominant arm is injured in any way, have you trained enough to draw and defend yourself? Can you reach your holstered firearm with your non-dominant hand?
There is a thread going on called Weak Hand Draw and you may get some valuable information from there. Hope this helps.
IMHO I would probably think that the easiest way to accomplish a weak hand draw would be from the AIWB position. At least for me because that’s where I conceal carry and I can get to my firearm quickly. As a right handed shooter I’m thinking if you carry OWB at 4 or 5 o’clock you can reach around your back left handed and grab the grip. It’s more difficult if you have a holster with a thumb break/snap. It would be better and easier with a Kydex holster, no thumb break/snap. But with practice anything is possible. As Massad Ayoob mentioned in the article you should practice with unloaded weapons or plastic guns.
@Johnnyq60 the problem I have reaching around the back is not so much reaching the grip, but rather pulling it forward to get it out of the holster due to forward cant. It is significantly easier with my 3" barrel pistol than my 4" barrel. Therefore if I train with the 4", the 3" seems really easy
Edit: reaching around the front is about the same for both and much easier than reaching around the back, but I train both ways just in case.
I can’t think of any better way to train than to simply practice drawing with your non-dominant hand… unloaded, of course.
I also think every person is different. Your equipment and your body shape might necessitate a technique that others here won’t appreciate. So be it, we’re not you.
We also have to allow for changes to our carry position or equipment. Threat analysis will play into this. You may have to balance the speed and ease of your dominant hand draw against the speed and ease of your non-dominant hand draw. How much difference is there, and how likely is it that you’ll have to use your non-dominant hand? There’s going to be a trade-off.
I’m a bit of a broken record on this, but everyone has to find their acceptable level of risk. Otherwise, you’d never be able to leave the house.
I’d suggest to start here;
Thank you @Jerzy
I was going to try to do that when I got back to a “real” computer - I am old and have trouble doing everything from a telephone