What are folks using for 9rd mags? I tried a couple of the Wilson Combat 9rd mags a few years ago and they turned my RIA into a single shot. Most reliable I’ve found (for me) are the cheap 8rd Metalform mags.
Have any advancements been made that I’ve missed?

I run 10 round Tripp System mags. Their 9 round Tripp Cobra mags are good to go as well. Some have found that a EGW high shelf mag release is required. I have not found that to be the case with my STI Trojans. I have also had success running wilson .45 mags (both etm and 47d) through my STI 40's loaded to 1.185~ length... no issues in 12k plus rounds ytd. I think bullet profile will be a factor in whether true 1.26" 10mm rounds hang up in the mag tube or you have feed issues.

I will 2nd the vote for Tripp. They are very solid and I use them for both 10mm and .45ACP, and have yet to have a hiccup with them. Plus, they are a Central Texas company!

thanks. I hadn't heard of Tripp before. Looks interesting.

USA, and Texas to boot... win/win!

I have no first hand experience with 10mm 1911’s but I AVOID 10 round 9mm magazines altogether and flush fitting 8 round 45 acp magazines.

Both my 9mm Colts run reliably with factory, Mec-gar and Metalform 9 round magazines. My .45 acp 1911’s all run great with KimPro flush fitting 7 round magazines. I have 15 of those Kimpro’s and the herd is slowly growing.

I may try a few Tripp Cobra 8 rounders or Metalform Elites (sold by Greg Cote) but they are not flush fitting later this year.

Maybe stocking up on more good 8 round 10mm magaines is the way to go?

The GoTo magazine that I have been using is the Devel/Shooting Star/Chip McCormick design. I have had those magazines in my 1911s for about 40 years now. Mostly in the 45s and the 10MMs

My second choice for those guns is usually the MetalForm magazines or the Pachmayrs. My 9MM 1911s really like the Pachmayrs

In my 38 Supers and 9x23s I mostly use the MetalForms

I have had bad luck with the 3 or 4 Wilsons that I had in 45ACP and just don't buy them anymore.

I have never tried a Tripp so it is hard to comment