Like I said, many of the cheap ones like the low end Weiser and Kwikset have plastic cylinders.
Then, to top it off, if you have a slightly upgraded model they stuff it with security pins.
Now, believe me when I tell you this crappy thermoplastic has no feeling. Its just not rigid enough. I can understand, it has to withstand cold, but its flexible so it sucks.
Couple that with spool pins, and you have a mess. The pins don't want to set, overlifting doesn't work right, because the tension needed to hold everything up deforms the cylinder, and it just goes down hill from there.
Install the lock "upside down" and your pick gun becomes an exercise in frustration, and can potentially break springs while gravity pulls key pins past the shear line.
I have run into this senario time after time, and eventually I get it, but on at least a few occasions I have had the cylinder pop out in my hand, and then had to put the entire thing back together once we get the key.
Oh, they can be all kinds of fun.
Romstar