I have heard it can happen with certain types of extensions. I forget the name of the manufacturer that people have had issues with. Don't see how it could happen with the stock flat base plate. I have a few mags with the Pierce +0 pinky extension. The +0's do feel a little more comfortable when just normaly gripping the gun. But they have not for "ME" enhanced precision in firing, wether rapid or slow. I don't use them much as the little extra concealability of the flat stock base plates is a plus. If I shot noticeably better with them, I would give up the extra space they take (which is not too much). I know it seems logical to have a place for the pinky. But the 26 was designed to fit in the hand as is (without extension) and actualy does for many people shoot just as well without the extensions. I think the exception would be someone with out much hand strength such as young men, smaller men, women, etc. I am not large at 5'8 but am pretty strong for my size/weight and use my hands alot in work, so grip/hand strength is not a problem. If you do not have sufficient strength with only two fingers plus thumb gripping the frame then I think the pin ky extensions would be a great idea. But you may want to use a stock mag and see if you and the wife can get used to it. It may just pay off and be a little smaller if you are trying to conceal it as much as possible.

As far as a solution to the blisters. I think it may only be solveable by trying a different brand of extensions. Try Glocktalk.com, there is alot of talk about these on there. I forget the name of the manufacturer of the ones that cause the issues, but I know most people that have used the "Pierce +0" extensions have all had luck with them (from what I have read). It is the plus capacity extensions and the other main manufacturer of extensions that normaly give the symptom you describe.

Good luck whatever you do! Try the stock mags.....

we're back to the stock 10 rd mags now, no problems. Wife originally wanted extensions cuz her brother's 26 had them, but the Pearce ones I got were pinching badly.

I tried a 12 rd mag for it that didn't pinch, but she's decided she prefers the grip with the pinkie slipping under anyways, so back to the stockers it is!

I was having this problem because of the sharp edge on the extensions. I took some 220 grit, then 400 grit and smoothed out that edge. Much better.