Re: Accuracy node Vs. Barrel Harmonics
Google the following....
Creighton Audette ladder test
Google the following....
Creighton Audette ladder test
Re: Accuracy node Vs. Barrel Harmonics
This is the theory:
http://www.the-long-family.com/OBT_paper.htm
This is it in practice:
http://www.snipershide.com/forum/ubbthre...602#Post1087602
This is the theory:
http://www.the-long-family.com/OBT_paper.htm
This is it in practice:
http://www.snipershide.com/forum/ubbthre...602#Post1087602
Re: Accuracy node Vs. Barrel Harmonics
Optimal barrel time OBT
Optimal charge weight OCW
And Audette Ladder are all related to accuracy nodes.
OBT is a theory about how the pressure wave of the powder burning travels up and down the barrel. Here, you want the wave near the action as the bullet leaves the muzzle. Thus, the muzzle is least disturbed, and the bullet flies true.
OCW is a theory about how to find an accuracy node and then find out how wide a charge weight will still be acceptably close to that accuracy node. Here, you are looking for an accuracy node by charge-weight, not by barrel time as above. But the same physics is taking place in the barrel.
Audette ladder is a theory about shooting and how the muzzle of the barrel is moving around when the bullet leaves the muzzle. The place where the barrel is not moving is where the accuracy node is supposed to be. This should be where the wave in the barrel is farthest from the muzzle and closely aligned to OBT.
There will be 4-6 accuracy nodes from minimal charge weight to maximal charge weight. The reloaders job is to identify those nodes for his gun(s).
Optimal barrel time OBT
Optimal charge weight OCW
And Audette Ladder are all related to accuracy nodes.
OBT is a theory about how the pressure wave of the powder burning travels up and down the barrel. Here, you want the wave near the action as the bullet leaves the muzzle. Thus, the muzzle is least disturbed, and the bullet flies true.
OCW is a theory about how to find an accuracy node and then find out how wide a charge weight will still be acceptably close to that accuracy node. Here, you are looking for an accuracy node by charge-weight, not by barrel time as above. But the same physics is taking place in the barrel.
Audette ladder is a theory about shooting and how the muzzle of the barrel is moving around when the bullet leaves the muzzle. The place where the barrel is not moving is where the accuracy node is supposed to be. This should be where the wave in the barrel is farthest from the muzzle and closely aligned to OBT.
There will be 4-6 accuracy nodes from minimal charge weight to maximal charge weight. The reloaders job is to identify those nodes for his gun(s).
Re: Accuracy node Vs. Barrel Harmonics
I ran a charge weight test @ 300 meters out of a 6mm BR a few years ago. My charge weight variation was unbelievable. I could vary more than 2 full grains, and printed less than 1.5 inches @ 300 meters. No kidding. There's value in determining optimal charge weight.
I ran a charge weight test @ 300 meters out of a 6mm BR a few years ago. My charge weight variation was unbelievable. I could vary more than 2 full grains, and printed less than 1.5 inches @ 300 meters. No kidding. There's value in determining optimal charge weight.
Re: Accuracy node Vs. Barrel Harmonics
Also some rifles are forgiving and others are picky bastards. I tried an ladder test at 200yards with a .270 and ended up with a round group the was a bit under 3/4moa. The same day I ran a ladder with a .223 and had a vertical group measuring over 4" and moved in a diagonal pattern from left to right as the charge went up....
Also some rifles are forgiving and others are picky bastards. I tried an ladder test at 200yards with a .270 and ended up with a round group the was a bit under 3/4moa. The same day I ran a ladder with a .223 and had a vertical group measuring over 4" and moved in a diagonal pattern from left to right as the charge went up....
