I always strip them down and clean everything and lube it up good. That way I know it is lubed and not any crud where it don't belong. I'm not a cleaning nut by any means, but always the first time before shooting.
I clean EVERY gun I get BEFORE I shoot it.
Who knows what is in the barrel/action that can cause a problem. Too much oil/grease in the barrel. Poor lube on the operating parts.
Who knows w/o a decent cleaning.
I always, and i mean always clean any barrel thats new to me. Or if a friend brings over a new gun, it gets a cleaning.
Its cheap insurance, and its amazing how much crude comes out of a new barrel.