Oleg, honest buddy ... save your ammo. It just isn't necessary. And, Art is so right - this danger is way over-rated. Hell, years ago we'd sometimes hunt
all weekend for a rattlesnake to catch, and not see one. And, we were looking hard for them, and knew what we were doing.
I agree about Texas - that's where the biggest Western Diamondbacks are found (Crotalus atrox). The biggest rattlers in the U.S. are in the southeast, mainly Florida - the Eastern Diamondback (Crotalus adamanteus). It was an Eastern Diamondback that bit me once, due to my own stupidity ... fortunately, it was a 'dry' bite. As I recall, about 25% of the time a poisonous snake doesn't even inject venom.
Come out to AZ sometime and visit me - we'll introduce you properly to the local hot stuff.
Take care. Regards from AZ