First, installing grip screw bushings, in this case, on an aluminum-frame weapon. John M. Browning used bushings to provide enough depth for a longer grip screw, while not increasing the thickness of the frame. That's one reason why the M1911 is relatively thin, because the frame is no thicker than needed to hold a bushing to hold the grip screw.
Unfortunately, Browning chose a hole size and thread count that is not used by anything else on earth. He could have designed something that used a standard piece of tooling, but noooo, it's an oddball size that your average hardware store never even knew existed. Here's a set of bushing tools you'll need for a proper job.
The punch on top is used with the busing staking tool below it. Underneath that is bushing itself, with the unique super-fine threads that screw into the frame. Underneath that is the special tap that you must have to clean up or re-tap the threads in the frame. Bushings are only a couple of bucks each, and can be considered expendable. The frame of your handgun isn't.
Because the Kimber has an aluminum frame, and I was screwing in the bushing (rather than the grip screw), I was afraid the threads might have problems, so I ran the tape through the hole to make sure everything was still good. Then I used a special screwdriver bit (not shown) that has the correct-thickness screw driver slot, and an outer shell to protect the bushing. After that, I then used the staking tool on all four bushings to prevent future problems.
The punch goes through the top bushing so you can stake the bottom one with a whack from a hammer. Since the grips started to loosen up after the first firing, I thought the screws needed tightening. But it was the bushings themselves that needed attention. So I tightened and staked the first three, and then installed another for hole #4.
So now I have the Covert Ultra with regular grips back on, and a good chance that this problem won't be happening again. I'll stake the other .45s if it seems that grips screws start loosening after firing.
Kimber did use red Loctite on the stock bushings when one of their people installed the Crimson Trace laser grips. Perhaps that's why three bushings held, even though the screws loosened up. On the fourth, he must not have paid enough attention, and used the Loctite on the screw, and not the bushing. I'm left with a $350 gadget that has the screw and bushing permanently attached, until I figure a way of getting them off without destroying the grip.
With what I've learned shooting the 1911, and handguns in general, I'm not so sold on lasers any more for handguns. I've also learned a lot more about proper grip, and trigger finger positioning, which is not so absolutely critical on a rifle compared to a handgun. And as I've worked on these handguns, and gotten more faith in how they work, and what I've done to them, I find myself thinking less about their own internal workings, and more about my own. I now have a short trigger on the Ultra Covert, and am aware that when I see holes on the left side of the target, I have to correct my finger position on the trigger.
I'm getting better at it, and just need to make a habit of getting it right the first time. I also shoot at 10 yards, which is almost 50% further away than the standard "defensive range". If I can be good at 10, I should also be good at 7.