Hi Ron,

Great shooting!

Air density is what I believe is messing with your drop verses dial setting. as you posted you were shooting in 9* and 15* temps. Even with your altitude being 4000+ ASL the cold temps make the air denser, warm air expands becomes lighter, cold air contracts and becomes heavier. The cold denser air creates a great deal more resistance for your somewhat less than streamlined projectiles.

I know that 50BMGs are not muzzleloaders but can I be allowed some leaniance in using one of mine as an example of how air temps (air density ) affect bullet drop.

At the family farm we have a 1000 yard range, we regularly enjoy shooting various firearms at great distance.

On an average summer day some where around 70*+ - my chosen loads will require 38 to 39 " of elevation adjustment to be right on our 1000 yard gongs. We shoot more in the winter than summer because of free time and such. At 32* +- shooting same loads, same rifle, same projectile, same scope, same set up, bench, muzzle brake. even same shooters, it will take a minimum of 44 " of dialed in adjustment to be right on the same gongs. This example is with a very High BC projectile compared to a Blunt Pistoly Boolit.

I believe Ron that this summer if you get the chance to set up in the same spot you will be amazed how much better that Pistoly Boolet pushes threw the air. You Dials will probably be very close.

Great shooting,

Ken

PS: There is a very good chance I will be visiting Rapid City this coming Spring/Summer. Just a warning! The Wife and I just haven't decided on a date yet.