6.5 or 7 mm

[Cienfuegos]

It is better a 7 mm 284 or take advantage of the CB of a 6.5 mm.
Here is a comparison of wind drift 90º 5 mph CB of 6.5 and 7 mm with speeds used by me and compared with 300 WSM of my competitors.
Distances 300 meters, 600 yards and 900 yards. Measures in inch y cm and subtracted to calculate spaces.

 

 

[Cienfuegos]

Datos comparativos pulgadas y cm

 

 

 

CM.xlsx

[Ronin]

I think the table speaks for itself really, the higher BC 7mm will out perform the high BC 6.5 mm's at modest velocities.

2850fps being a "modest velocity" with a 284 Shehane

What they wont do is beat a high BC 30 cal bullet, but then the 7mm doesnt impart barrel torque (unsettling the gun in the rest), high recoil (unsettling the shooter) and vertical stringing.........

 

 

[Catch-22]

I would agree with Ronin above, though I don't think the table comparison is actually quite 'fair'. 

You can push the 139g Scenar faster than your figures if using a bigger case than say a CM or .260rem. So, your table should really show the difference between lighter 6.5mm projectiles pushed at faster velocities than the 7mm bullets at more moderate velocities.

I think you'll see a narrowing in the difference between the bullets but shooting the 6.5mm bullets at higher velocities will come at the expense of reduced barrel life.

Overall, I agree that the 7mm will still come out on top AND will provide better barrel life when shot at the moderate velocities as noted. 

[Cienfuegos]

2890 pies para mi 139 es lo que hace que mi bronce dure más de 10 tiros. Algo importante. Y con lo que siempre he logrado estar a la sombra de los 300 WSM, en mi país. Tal vez usando mejores coeficientes como hornay (no estoy seguro de que sea tan cierto como el que anuncian), berger, etc ... pero los costos se disparan. Ahora estoy pensando en un 7 mm, también a velocidades de crucero de 2850 pies, para poder hacer frente a más igualdad en el campo "mejor parque eólico" que tenemos en Galicia.

 

the values 0,0,0 are the estimated ones for a 300 wsm ... compared in drift.