Re: using the slide release.
Some guns make it difficult. Others gun makers tell you to USE that method: check the Kahr users manual.
I've only had one type of gun that really made made it easy to use my strong hand thumb to release the slide -- A glock with an extended slide release. I've also had a customer CZ-pattern gun with extended controls that works pretty well. Several others guns close the slide if I slam the mag home forcefully enough. (One pro shooter I know tweaks his game guns so THAT the slide slams shut every time he slames in a mag.)
If you feel you must must use the slide stop and find it difficult, use your weak hand... as you push the mag into the grip, move the weak hand on up, and use several fingers of that hand like a claw to find and engage the slide stop. With a little practice, it'll almost as quick as any method and, important to competitive shooters, you can keep your gun up at eye height more easily, and your eye on the next target.
Note: the
hand-over technique, where your hand reaches across the top of the rear of the slide or the rear sight also works better than the slingshot. When doing it, these shooters forcefully push the slide back and let the hand continue to the rear. (Do it too forcefully, and you can hit yourself in the face.)
You see the top competitive shooters doing it three ways: 1) slide release, 2) weak hand, and 3) hand-over. The only competitors who still use some form of the slingshot technique typically aren't among the top shooters.
You can even use the hand-over method when doing the TAP-RACK-BANG procedure.