In my youth I bulged two bores of the cylinder of a S&W Mdl66, and cracked the forcing cone, because I didn't realize how heat sensitive Unique is.
I was shooting mid strength loads right out of the manual, nothing hot, and my buddy and I had been shooting it since January.
In mid June we went to breakfast, and out to the range. We hadn't been out since April. This was Vegas. The temp was around 100 in the shade. The guns were in the trunk of a navy blue Honda. They were a little warm to the touch when we got them out. But, we both set targets, loaded up and started to shoot. The first round seemed wrong and hit high. The second had blowback bad enough it stung my hands. I knew I had messed up bad when I couldn't eject the brass without using a hammer and a drift.
Lesson learned: Unique is not friendly.