How long does it take to caliper/mike out the bullets recovered, weigh the fragments, and determine preliminary ballistics data, anyway? (None has been released yet).
Or is someone waiting for the evidence to become 'misplaced'...like a certain steel door at the last Waco Massacre.
Not long at all. If the slugs are highly fragmented you can bet they came from rifles. There are exceptions to some specialty handgun cartridges that will fragment such as power-ball ammo. With power-ball the lead is intact but highly mushroomed. The metal jacket is designed to peal away and it makes some ugly cutting edges. However the base is relatively not deformed and easily miked to determine caliber.