Just watch the first version of 'Tremors' and I suspect that you will get all of the gun and ammo advice you need to answer your particular question. Hey, if'n it'll stop a giant earthworm it will take out a measly shark........
I thought Graboids were in New Mexico;)
you need to go with something that has penetration. Any good hunting rifle round with a pointy tip should be fine.
Should probably go with something that will go through a door without deflecting too.
I sure am going to be glad when this autoplay gets off the front page.
Sorry it isn't autoplay for me, I'll see what I can do.