Looking at possibly buying this lens, but raising an eyebrow about the claim that only a "slight binding" caused this gash, anyone have any thoughts? minor concern? stay away? seller claims it works as normal
The lens is probably fine but I'd be concerned about buying gear from someone who would brute force a 'binding' lens for it's entire length before thinking to stop and see what the problem is.
If this was caused by a fall or hit, it will very likely have some decentered elements, and will be soft on one side, or both, or a corner, or something like that. I'd only consider it if it was less than half price, and I had the will and time to open it and fix any decentered elements.
If it has a zoom lock (I don't know this model), it's either that, or a bump deformed the barrel and the lock was stuck and made this. Former seems more plausible to me.