EFFECT OF WIND DRIFT ON P. R. B.

[j-houser]

Went to the range yesterday and shot 60 cal PRBs at 100 yards. The vertical groups was around 4 inches high but the horizontal groups shape was pushing 8 to 10 inches. It could have been my sight picture but am questioning how much wind drift a .590 prb at 1100 fps. with a 9 mph variable wind would create.  Cant find a wind drift chart on the internet or TMA. Any help would be much appreciated.

[biliff]

A rough rule of thumb is one inch of drift for every one mph of crosswind at 100 yds.

Smaller balls tend to be a little worse, large balls tend to be a little better.

Link is to a RB ballistics calculator.

Rb ballistics

[Thunderhawk1828]

Billif

thanks for the RB ballistics calculator

Thunderhawk1828

[j-houser]

My apologize, I thought I had replied yesterday but it didnt post. Thanks also for this valuable information. Ran off copies of my specs to take to the range. Will try to find better weather conditions or time of day for my next trip to the range.

May you never load another ball without a powder charge

[Riley/MN]

Smaller balls tend to be a little worse, large balls tend to be a little better.

That is what I always have said.....

[Geezer in NH]

Wind flags are your friends. If none put out use grass, leaves etc. Just keep a consistent condition and use that one.

After many times doing this 2-3 years you will learn how each affects the shot. To me there is no other way to do it but I had championship mentors helping me learn.