If you are going to be stupid and shoot handloads from someone you don't know, you really shouldn't shoot them in a Garand, a firearm with a gas system that must use specific ammunition, so much so that even most standard commercial .30-06 ammo will cause damage to the rifle if fired in a Garand, abeit non-catastrophic damage.
What happens when you don't follow these simple rules?
You get to thank God you're only out a $1000 rifle and some pain in your hand.
Yes, that is in fact what's left of an M-1 Garand (Springfield Armory reproduction, thankfully, although they still used many USGI parts). You should really follow the link and read the whole thing, as the other pictures are even more incredible. The force of the explosion was enough to blow sections of the handguard 35 feet to both sides of the shooter.