G'day;
Thought i'd post this up incase anyone was interested.
We have completed testing 308 projectiles in the our McMillan CS5 rifle.
The rifle has a 12.5” barrel.
We have drop and energy charts too but the chart we use to discuss hit probability at distance is the wind drift attached.
All loads were 2.82” except for the 110gr V-Max which was 2.74” COAL.
Numbers in the columns are in tenth mil increments. You’ll notice in a few instances there’ll be a cell that shifts to a lighter colour then picks up again. This is because we are measuring in 10ths of mils. The ballistic app will round up or down so the difference is going to be marginal.
We used to use centimetres but it was too confusing and considering the fire is going to be applied using a mil hold anyway, we shifted over to this to keep the results cleaner and clearer.
AR 2208 and AR 2206H are Australian powders and are the equivalent of Varget and H4895.
The black cells are where the bullet enters the transonic zone and we therefore deem this to be the end of the bullet’s predictable flight path.
Yes the bullets will transfer through this zone but we have to set a limit somewhere.
The coloured squares in the Fields are just to show where each of the projectiles separate from each other as a quick reference.
We picked up this habit from submitting work like this up the chain of command for viability, upgrade, replacement programs. The people holding the purse strings typically know fuck all about the thing they are authorising expenditure on and I’ve found putting coloured cells of “green good, red bad” gets the message across easier.
Whilst 12.5” isn’t a long range barrel, we are still going to load up and take the rifle into a Service Rifle Competition and try and see where it fails and where it succeeds. To that end, the 208gr Bergers are going to be our projectile of choice.
Thought i'd post this up incase anyone was interested.
We have completed testing 308 projectiles in the our McMillan CS5 rifle.
The rifle has a 12.5” barrel.
We have drop and energy charts too but the chart we use to discuss hit probability at distance is the wind drift attached.
All loads were 2.82” except for the 110gr V-Max which was 2.74” COAL.
Numbers in the columns are in tenth mil increments. You’ll notice in a few instances there’ll be a cell that shifts to a lighter colour then picks up again. This is because we are measuring in 10ths of mils. The ballistic app will round up or down so the difference is going to be marginal.
We used to use centimetres but it was too confusing and considering the fire is going to be applied using a mil hold anyway, we shifted over to this to keep the results cleaner and clearer.
AR 2208 and AR 2206H are Australian powders and are the equivalent of Varget and H4895.
The black cells are where the bullet enters the transonic zone and we therefore deem this to be the end of the bullet’s predictable flight path.
Yes the bullets will transfer through this zone but we have to set a limit somewhere.
The coloured squares in the Fields are just to show where each of the projectiles separate from each other as a quick reference.
We picked up this habit from submitting work like this up the chain of command for viability, upgrade, replacement programs. The people holding the purse strings typically know fuck all about the thing they are authorising expenditure on and I’ve found putting coloured cells of “green good, red bad” gets the message across easier.
Whilst 12.5” isn’t a long range barrel, we are still going to load up and take the rifle into a Service Rifle Competition and try and see where it fails and where it succeeds. To that end, the 208gr Bergers are going to be our projectile of choice.
