This is with Tim Sellars of Sellars ballistic technologies
It goes over some really cool stuff on barrel harmomics and "positive compensation.
as best I can understand it positive compensation is tuning your load so that, as velocities decrease the bullets hit higher to compensate for the velocity loss and reduce vertical stringing. making sure the barrel is moving upward in its vibration as the bullet is leaving the barrel so that slower bullets exit higher.
typically if you used a ballistic calculator and put in 2 different velocities you would get 2 different points of impact, 1 high and 1 low due to the increased fall of the bullet due to its lower speed.
the testing process basically constitutes to firing 6 shots, 1.0g of powder apart at a horizontal line going from right to left going from min charge to max charge
when reading the target normally, left to right you will have your fastest charge first. as you progress right you have lighter and slower charges. the bullet should be rising as you progress right. at some point the bullets will begin to drop off significantly faster than it was rising. any point where the bullet is rising is a safe area. stay away from where the bullet drops.
in theory, since the bullet is rising as the powder charge decreases, it should negate changes in ES/SD of a normal load and keep the POI the same, compensating for the variation within a normal load.
Really interesting concept.
https://www.youtube.com/watch?v=xvtllOH_8BE
It goes over some really cool stuff on barrel harmomics and "positive compensation.
as best I can understand it positive compensation is tuning your load so that, as velocities decrease the bullets hit higher to compensate for the velocity loss and reduce vertical stringing. making sure the barrel is moving upward in its vibration as the bullet is leaving the barrel so that slower bullets exit higher.
typically if you used a ballistic calculator and put in 2 different velocities you would get 2 different points of impact, 1 high and 1 low due to the increased fall of the bullet due to its lower speed.
the testing process basically constitutes to firing 6 shots, 1.0g of powder apart at a horizontal line going from right to left going from min charge to max charge
when reading the target normally, left to right you will have your fastest charge first. as you progress right you have lighter and slower charges. the bullet should be rising as you progress right. at some point the bullets will begin to drop off significantly faster than it was rising. any point where the bullet is rising is a safe area. stay away from where the bullet drops.
in theory, since the bullet is rising as the powder charge decreases, it should negate changes in ES/SD of a normal load and keep the POI the same, compensating for the variation within a normal load.
Really interesting concept.
https://www.youtube.com/watch?v=xvtllOH_8BE
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