I took a winchester USA brand .223 ammo and measured the bullet bore with a caliber, and found out its really .225 instead of .223 is it safe to fire? how big can the bullet be before firing it becomes dangerous? also I have some unknown bullets which I measured with a caliber and it turns out to be .308.. if anyone wants it tell me and I will send it to you... free of charge. I got a bunch of it and i dont have a real need for it... (just if you are going to reload with it verify it with a caliber!)

Most ".223 Remington" bullets are .224 across. Most "30 caliber" are .308" across. Nothing weird about your measurements.

Most calibers don't exactly measure what's on the label. You need a good handbook to find the exact measurements.

.38's are actually .357" in diameter
.44's range from .429" and .431"
etc.