Dispersion MOA on antinodes

[poi78]

I have noticed that when I am developing loads using the OCW methodology, that my accuracy nodes line up well with many of the GRTs OBT predictions and the resulting dispersion is generally just under 1/2 MOA (limited by my shooting ability). However, on the antinodes, I see up to (sometimes) 3 MOA of dispersion. I was curious; what are you guys seeing as a maximum amount of dispersion on your accuracy antinodes using your bolt action rifles?

 

[supercorndogs]

Dispersion in my tests usually is under 1 MOA for 3 shots of any given charge weight.

 

[WB300]

What caliber, cartridge, and barrel profile?

Longer thinner barrels are harder for me to fine tune a load, but I know my Load-Fu is weak.

 

[supercorndogs]

I would say if a rifle doesn't hold sub MOA for the entire test, any shift in POI would be hard to detect.

 

[poi78]

What caliber, cartridge, and barrel profile?

Longer thinner barrels are harder for me to fine tune a load, but I know my Load-Fu is weak.

Heavy barrel profile in .338 Lapua. The barrel length is 24”. I’m using Norma brass with H4350 pushing 185 grain CXs at the spec COAL. When I come out of a node, the dispersion really opens up. Not sure exactly why this is occurring. I’m shooting off a front bipod with a rear bag.

 

[poi78]

I would say if a rifle doesn't hold sub MOA for the entire test, any shift in POI would be hard to detect.

Agreed. I have been using the dispersion size to judge accuracy nodes with (best that I can), shifts in group centroids to try to inform node stability.

 

[WB300]

I don't have experience with the 338 LM, but I had a 29" #1 contour in 30-06 that I eventually put between 2 trees and pulled. My blood pressure went back to normal after that.

 

[poi78]

.

 

[poi78]

I don't have experience with the 338 LM, but I had a 29" #1 contour in 30-06 that I eventually put between 2 trees and pulled. My blood pressure went back to normal after that.

. Been there before with a 5 iron on the 4th hole pond. It took a permanent bath.