Thanks for that guys.
Ok, here's the range report. Silly me, I field stripped the gun before going out just to inspect and oil it. I reckon I should have done the same with the mags. 🙄
So first of all, NONE of the six mags that came with it would drop if the slide was locked back. You couldn't even rip them out. Drop the slide and the mags drop free. Mag catch seems fine. Removed the Hogue grips and the magwell flare/extension and the problem disappeared. No problems with the stock grips installed. No witnesses marks on any of the mags to suggest the grip screws were too long. I'm going to do a little more diagnosis on that issue. I actually liked the Hogue grips more than I thought I would, so not giving up on that just yet.
Then, I found several of the mag followers dragging badly, causing some failures to feed, but it was clearly a mag issue, not a gun issue. And it seems they're all just Kimber factory magazines with bumpers attached to the bottoms. Weird. So they all need stripped, cleaned, and oiled.
Overall, the gun is a peach to shoot. Recoil was very mild so follow-up shots were easy. My concerns about the grip safety were totally unfounded. It fits my hand well, so engagement of the grip safety was always positive. The jury is still out on the stock sights for an old guy like me, but in all fairness, my contacts are kinda dirty right now. I'll start there. 🙄 I do think an extended slide release would be a welcome addition. I have one on my full size 1911 and like it, so I may do the same here.
It had no issues feeding either the 115 grain Blazer brass, or the 124 grain +P Speer Gold Dot JHP.
So I reckon I need to service the mags, see if I can sort out the mag ejection issues, maybe order an extended slide release, and go shoot it some more. I think these are all simple issues to resolve.
That's all I've got for now!
D Dave