What Happened to the M 21 X M 21 Sniper Rifle?

The fbi got five rifles that had been modified by the army marksmanship unit. They were known as m 21 x m 21, and it was a snipe rifle system. The barrels with a rate o rifling twist of one turn in every 11 and a quarter inches. Fbi claims they lost one of how do you mose an experimental snipe rifle? An had claim to have no traces to where it's gone. It also got five thousand rounds of some custard loadind ammunition that contained the very brand bullet that was pulled out of king's body.