Quite frankly, I have to ask, why does it matter? Why do you need to know this maximum range?
Are you shooting to establish some sort of record or to achieve a maximum record distance? Is there some sort of restriction where you shoot?
First I am unaware of any software ballistics calculator that compute this data for larger than one inch. But I will bet it's out there. Send an email to all the different groups advertising ballistic software and see if one of them will help you.
Most likely you are going to have to figure it out yourself.
You are going to have to do some careful studies. You are going to need to learn as much as you can about golf balls.
I would start with
www.google.com. Query "Ballistics calculators", "Greenhill Formula" or "Ingalls tables". Query phrases like "determining ballistic coefficients", "ballistic coefficient of a golf ball", "golf ball speed"or "golf ball velocity".
The better way to do it is the old fashion way. Shoot your mortar.
Don't worry about muzzle elevation. First keep it simple and leave that variable out. Second Coehorns were of fixed elevation and range was adjusted by adjusting the powder charge. Third maximum range of your gun is restricted by the maximum charge of your gun.
Use a starting load and fire a series of shots recording charge weight, time of flight and distance. Als record temperature wind velocity and wind direction. Establish an average figure for the charge.
Increase you charge weights in increments until you reach maximum charge, recording the data as you go along.
Something you will learn fast is that shooting golf balls beyond 200 yards isn't very enjoyable. They go out sight to fast and you can't /don't see the impact.
I know this doesn't answer your question, but I hope it helps you find it.
By the way should you follow through and do this testing, please report to us the results. We would all like to see it.
