So I got a batch of loose Speer Gold Dot .40 Ammo. It has it looks light knickel casing. Any way to tell what grain it is? it doesn't say on the casing. Also I see alot of you guys love that ammo for home defense but also for cheap practice ammo. Is it better for 1 or the other? I don't want to waist good ammo on plinking but if it's good enuff for home defense I'll use it. I'm kinda a Corbon guy but if this is good stuff I'll use this. Thanks!