I think the hole for the safety detent on my lower is just a tad narrow at the top not allowing the detent to engage the safety lever as positively as it ought to. Previously someone had recommended taking a size ? Drill bit in a hand tool and just giving it a couple turns to lower the counter sunk hole just a tad. But I'm not sure what size bit I need exactly. I want to say the person. Said size 11? Thats pretty big..im barrowing a #47 from work but if Anyone knows it might save me a few trips.

This info is from CNCGunsmithing, they sell AR jigs and supply a tutorial, I copied the info regarding the selector dent, hope it helps.

The next hole I decided to drill was the safety selector detent hole. This hole is a two-step process. It uses a (D) 5/32 drill for a depth of 0.188” and a (C) 1/8 drill all the way through the hole until you reach the 3/8 selector switch hole. After the detent hole is drilled, it should hit the center of the selector switch hole.  The location of this hole is not extremely critical, so I just scribed a couple lines, punched the hole location and drilled the hole. To scribe the location lines, you’ll need an X and Y measurement, and then you drill where the two lines cross. The first line I scribed was the distance from the back of the buffer tower to the center of where the safety selector detent hole will be. I set the jig on the drill press table with the buffer tower facing down, then took my calipers and measured up 1.931” and made a scribe line.  Here’s a pic showing that…

Thank you!

Done, seems to have helped a bit. But I'm starting to think it's the safety selector that's the problem, it has some play in it on safe, but clicks on and off more positively now.

Could be a worn selector. I had an original dimpled selector that was a pain to get to work well.
Try another selector if possible.

It might be that the counter bore isn't drilled to spec.
But one has to be very careful not to drill the counter bore deeper than the .188" , or the selector will be very difficult to rotate out of the detents.

I installed it new. I was only twisting the bit by hand removing a very small amount at a time. Didn't remove much. Next time I'll switch the lower recievers around and put this Ballistic Advantage receiver on my carbine and the carbines PSA on this rifle I hate the pictograph crap anyway. When I do that I'll pull the selector out and see how well the detend matches up to the ugh, hole? In the safety selector. Very real possibility I just need to take more material out. I'd rather do it 5 times before getting enough removed than to much.