Just buy the chronograph. If you're an engineer, you make enough to buy one, because you should also be smart enough to not have over extended your way of living beyond your means, and dropping $100-200 on a chrony isn't $hit in the scheme of things.
I'm an engineer too, used to work in munitions development even. First - velocity doesn't mean $hit. Go shoot at range in different conditions, that is all you need. Second, even with velocity, as mentioned above, the published BC's are generally bogus, so you still can't rely upon published data to make shots at range without DOPE. If you shoot without a chrony, you have an undefined system - the velocity AND BC are unknown. Can't solve it without making some BS assumption for one or the other.
