I wasn't sure if this is the place for this question or if it it should be in the reloading section, anyway, here goes.
I was cleaning and sorting 45 ACP cases (some range brass) and found one(Winchester) case with a flash hole that is about 1/8" dia. All others are about 5/64" dia.
I recall seeing a pamphlet about Speer plastic bullets (primer only, no powder) that stated: "To prevent primer setback in 45 ACP cases, open the flash holes with a 7/64" drill. CAUTION: Cases so altered must not be used with conventional loads."
My question is what does happen with an oversize flash hole with a conventional load?