Has this ever happened?

Was bottling some cider last night and some bottles broke just below the cap. I'm thinking defective or weak spots in glass.

were they twist off's.... I've heard those are thinner then the standard cap bottles. That or stop using the "guns" so much when capping

I have also heard of people who found their cappers were damaged. Inspect the parts that grab the neck.

Same thing happened to me when I was bottling my last batch. One of the two bottle types I used were twist offs. It broke the first time I kept trying to use my capper which I expected after much reading on here, so what I had to do was push down until I felt a good amount of pressure was applied, quarter turn the bottle and cap again, and repeat until you've equally capped the whole bottle. Bottles are now carbonating and they have worked great! You might be pushing too hard, or there could be a defect with your capper but if not, just stop working out muscle man Haha

Its happened to me on non-twist bottles. I think its mostly squeezing the capper to hard.

These were standard bottles

This happened to me when filling a 22oz just had one incident so far I said wtf took a pic and tossed the brew

This happened to me a couple of times. I was re-using bottles from a Canadian brewery. The bottles were not twist off. The glass was just thinner.