Okay, looks like the G22 slide was damaged back in 2009, as dated by the old photos I still have in Photobucket. I originally posted a heads up post regarding the problem here on this site as well as on Glocktalk (I originally posted the lot #s of the ammunition we had as well). Basically, I noticed a strange, semi-circular wear pattern on the breech face and chamber of the barrel on this particular Glock during annual inspection. Turned out, it was pretty bad scoring into the steel, so I forwarded photos directly to Glock, Inc. tech dept. and was promptly advised that it was not due to a defect in manufacturing, but was due to damage caused by the Blazer aluminum cased ammunition we were using.
At first, I though the tech was basically full of fecal matter, but I called CCI/SPEER directly and forwarded the photos and a description of what was happening with the Glock. The next morning, I received a call from a lady (I believe she said she was owner/part owner of the company). She told me that she would be having someone from their tech department contact me regarding the problem, which happened in quick fashion. Basically, the tech advised that the damage was indeed caused, in some part, due to the use of the aluminum casings. He said that it was a bit of a freak thing, but that they have seen it before. Apparently, it was a combination of the liberally loose chamber of the Glock, the aluminum casing and hot gases during ignition.
The tech believed that there may have been "flashing" from around the primer pocket, which in effect, caused a sort arc welder effect with the steel breech face of the slide. It also caused damage to the chamber of the barrel. CCI/SPEER paid for a new complete upper for the pistol and Glock returned the pistol to us free of charge. I would not have believed it, had I not been told so directly by CCI/SPEER staff. We still use the Blazer aluminum cased ammo for training purposes and we have had no further issues with it. I have used it since the early 90's with no problems at all. These days, I don't buy it simply because I want the brass casings for reloading.