The Shooter.
Read the whole text of the question please, looking for mechanical or component item...shooter not an option. Thank you.
I read it, gave the answer from my experiences as the shooter IS a component of the whole equation. The question as a whole is pointless to me because different platforms are prone to different weaknesses, if the weaknesses are even significant to begin with. No specific problem will be universal except the shooter.
For instance you've had some "Magazine" replies...... mags aren't a significant problem with glocks across the board, just like with many major platforms. However, with 1911s they can be a problem area as generally stock mags aren't GTG. In the same sense, smaller platforms can have spring problems fairly quickly from my experiences whereas a full size will be more tolerant etc, etc.
Sorry you missed the point. No soup for you! I was asking about "mechanical" components and the shooter was taken out of the loop; (see option "OTHER" in the poll...clearly says "besides the shooter" ...in other words, the shooter is not to be considered as a variable in this case please. Write on the board 100 times: "the magazine is the cause of most mechanical failures..."
Had I included "the shooter" as an option in the poll you would, IMO be right. But I didn't. So you lose. No soup for you today!
Nope I get the point, I was just curious as to the generality you're trying to make. It's clear now, but I won't be writing anything on a board because factory Glock mags aren't a problem, neither are XD mags from my experiences.