Mike from RKM / Hard 2 Hurt channel has some good practical info. He's a former SWAT cop who left the job and started teaching people how to fight so they could defend themselves. One of his latest videos covers actually putting your ability to get your gun into play in a close contact fight to the test. A lot of us probably don't do this. I've not done a lot of it - despite being a martial artist. Since moving here to Texas I have yet to make friends who I could train like this with. I had a couple people in Oregon I could do this with.
Just like pressure testing unarmed martial arts techniques, pressure testing your gear and skills is the way to see where your deficiencies are and where theory and reality diverge.