I've read a few times that you need to wipe off any lube on the shoulder of rifle cases before resizing.  Why is this?  What happens if you don't?  Also, totally different topic, why is that you don't need to trim pistol cases?

excessive lube on the shoulder will cause the shoulder to dent from hydraulic pressure as you resize the case, some of my dies have a hole drilled in the shoulder of the die so any excessive lube is relieved out of this hole instead of denting the case.

This is really only a problem with the thicker lubes like Imperial sizing wax and like, most spray lubes are so thin it wont dent the case even with it fully lubed, I lube my brass with Dillon spray lube and it covers the shoulder and I have never wiped any of it off nor have I ever had a case shoulder dent because of it, so unless your seeing dents in your case shoulders after resizing I wouldn't worry about it.

I've had dented necks with Dillon lube if I'd spray too much lube on the cases and size before the alcohol evaporates but since it evaporates so fast, it hardly ever happens.  60 seconds the alc's all gone



 

For guys that use Imperial or any other non-spray stuff, how do you get it in the case mouth and on the neck on bottleneck cases?  Do you just do one at a time w/ a q-tip or something?  Seems like using anything other than spray lube would take forever.

No need to lube the outside of the necks but the people that do lube the inside(I don't) usually run their finger across the case mouth since they are using their fingers anyway to lube the whole case and it wipes off just enough lube into the necks, but some use q-tips also, I have Unique sizing wax and will only use it if I need to lube one or two cases to resize for some reason, other than that I use Dillon(or like) spray lube only and a carbide expander that doesn't require inside neck lube and it doesn't stretch the case necks..

I still use my old RCBS lube pad.  It's pretty easy to overlube this way.  The result is dents on the shoulder.  Only harm is overworking the brass, and it does change the case volume, so max loads could be an issue.