I started writing an article about how "Gun Culture 2.0" is combining BJJ and such to try to get "gun grappling" good along with my thoughts. My thoughts are basically that thinking of it as "gun grappling" is both wrong and short sighted. It's just "weapons grappling" because human bodies haven't changed and what you have to do with your body and the way the opponent's body moves and breaks is unchanged also. It's just a weapon. "Pass the point," control the weapon/limb, inflict damage. Nothing particularly special.
I stopped writing it because, well, it's obvious. If you can find a martial arts manual with "illustrations" that include unarmed vs. armed, it looks pretty much the same, going back for centuries. Pass the point (void/move-out-of-the-way while moving inside the range), control the weapon/limb, inflict damage. Kung fu, Marrozo, FMA, "gun grappling," it's all the same. Boringly so, actually.
Further, the people who are investing tons of time thinking they are merging BJJ (or whatever) with guns are not going to be swayed or impressed (or may already realize this). Think they're going to be impressed if I tell them, "just go take a year or two of FMA to learn weapons defenses?" They've either already figured that out for themselves or, like Dorothy and those Ruby Slippers, won't believe it anyway. And the 2.0 folks who haven't gotten there yet? They're either still stuck thinking that the gun will solve all the problems and don't want to try adding a "martial artsy" thing in, or they already got there.
In either case, except for a very small subset, I'm either preaching to the choir or talking to the deaf. Talking to the deaf is just beating my head against a wall, and preaching to the choir is just an exercise in personal egotism so that people who already agree with me can congratulate me on how smart we both are.
So, when it comes to "gun grappling," well, it's just a weapon. The "rules" <ahem> for grappling against one are pretty similar to the rules for grappling against many of the others. Are there a few differences? Sure. But the differences are actually pretty small when you get down to brass tacks.
And what's more, at some point, it's not even "weapons grappling." If you boil it down far enough, it's
just grappling. The other guy's body still moves and breaks the same whether or not he's holding a weapon.
At the end of the day, if you want to include any weapon in your self defense training, learn to fight with it and against it (as well as any other common weapons you might face) at all applicable ranges. It's not Rocket Surgery.
This is where someone quotes Bruce Lee about punching.
Peace favor your sword,
Kirk