I'm wondering if someone can help me with this rifle I acquired from my elderly dad which he built back in the 70's. It's a 17-222 cal bolt action varment rifle with a 6x Banner scope by Bushbell. The problem is I don't know, and my dad can't seem to help, identify which ammo it takes as there appears to be more than one size of 222 case. He claimed he used a die on some ammo to neck the casings just right but not sure where the die is now. I can find different 17 cal ammo for sale but not sure which case it takes. My dad claims it shoots up to 3800ft/sec. Any idea how I find out what ammo it takes and approximate value? Thanks.