vertical dispersion question

[chuckbuster243]

I could not agree more... I shoot a group for my rifle at close to the same speed as in a match. The way I figure it is if my group goes to pot after three quick shots and I normally shoot 20 shot strings in competition I need to change something. I would rather know when I am on the range testing than in a match. My 308 F-TR gun takes a few shots to get warm and settle in to get the best groups. I know this and account for it. Matt

 

[Steve Blair]

My successful F-Class loads are just below full pressure, in a node where the velocity curve flattens for .4 -.8 grains. In that node, the velocity, ES and accuracy do not change much. That is where I want to be. At Raton, I had no load-related problems with vertical, whether 65° morning or 90° afternoon. I saw some vertical but can honestly attribute it to range conditions. [br]
My usual drill when load testing is to shoot five-shot groups at 45 second to one minute spacing, wait two minutes and shoot the next group. After finding the node bounds and center, I fire twenty-five rounds, over the chrono, in about twelve to fifteen minutes. There is usually some velocity increase over the string, say 10-15 fps, as the barrel fouls and heats. This is acceptable because I'm willing to apply a click or two as needed during a match string to maintain waterline elevation. Any significant velocity excursion during testing, whether high or low, is cause for rejection and possible rework. Just the way I do it.

 

[22BRGUY]

Awesome help from Gator and Buster....Thanks guys

 

[savageshooter86]

great info here.