Wendy, I reload for several 9mm's and one of them is a G26. Since I'm in CA, we are stuck with Gen 3 version. It takes all my reloads perfectly. Having said that, since I shoot pistol in an indoor range I end up with Range pickup brass.
When I reload it's pretty easy to spot Glock brass by the tell tale primer strike (at least where I shoot). Every now and then I'll see one with the bulge...
What I do is tumble, inspect and reload as usual, but before I put the reloads into my ammo cases, I run them through a Lyman chamber checker. I would say about 4 out of a 100 will not pass. Visually they look perfect, but sometimes it could be the bulge or the rim has a blemish/scratch that won't let it pass. (when I mean pass is they fall in and out easily! If they catch in any way they have failed this test)
These get run through the Lee Bulge Buster, and I use a 9mm Mak FCD die because the 9mm is a tapered round. You'd be surprised how much leverage you need to run these through the die. Heck I've even resorted to lubing the base a bit with some imperial wax to make it easier. BUT, after running them, and yes they are loaded, through they pass and shoot perfectly. This to me is just insurance that I won't have a FTF, or FTC.
To date this has proved foolproof to my shooting 9mm.