Thread: 270 Winchester ammo

Originally Posted by ariki

All were from same lots @grandpamac not trying to reinvent the wheel. Just trying to correlate accuracy to rifle I’m using.

Any way this is what Browning ended up

Heavy

Proj 135.3
Case195.2
Pow58.3
Tot 388.8

Light
Proj133.7
Case189.7
Powder56.9
379.3

If it has no statistical importance why is the cheap Fiocchi branded Performa and Sako ammo got a lot less deviation?
And secondly I have not accuracy tested the Browning ammo as of yet.

Greetings Ariki,
Interesting reading. To me the variation of 1.4 grains of powder is more of a worry than the 5.5 grains difference in case weight. Brass has a relative density of about 8.8 so the difference in powder capacity is only about 0.6 grains or about 1% difference. This would give a difference in velocity of around 10 to 20 feet per second. The difference in powder charge however would give a difference of around 60 fps, perhaps a little more. These figures are based on data in the late Ken Waters Pet Loads series. My experience with the .270 W is that it is pretty forgiving on variations of velocity so if these differences have any effect on accuracy, especially at shorter ranges, is unknown. Only testing will show that. In handloading we can measure all manner of things and assume that we can interpret what difference these measurements can make. Actual testing often makes fools of us. Been there and done that more than once.
All the best with your shooting and regards Grandpamac.