Originally Posted by MontanaRifleman
Is it possible the wind was affecting the steadiness of the rifle? When I shoot on windy days it's a challange for me to hold as steady as on calm days. Infact, I just can not hold extremely steady in anything more than a 5 mph crosswind that is pushing on my rifle. It bounces around, not much, but enough to affect accuracy. So I do not shoot for groups in those conditions. This is on a stout portable bench with sand bags.
Also, with all due respect to JE, who is an experienced contributor on this site, weight actually has little *direct* affect on resistance to wind drift. The only two factors that affect wind resistance are BC and velocity. A .277 bullet weighing 150 gr, with a BC of .5 and an MV of 3000 fps will experience exactley the same wind drift as .338 bullet weighing 300 gr and a BC of .5 with MV of 3000 fps. They will both arrive down range at the same distance with the same velocity, trajectory and TOF.
Having said that, weight is a factor in determining BC. Generally speaking, a heavier bullet in the same caliber of similar design will have a higher BC. But a smaller bullet with a greater BC than a larger bullet, traveling at the same velocity will buck wind better than the larger bullet.
This is not ment to be argumentative so don't take it that way .
It is a good subject to debate and we can allways learn something from others if we listen.
You are dead on about the wind drift under your conditions BUT your numbers are not apples
Most ,277 dia. 150 gr bullets are from.450 to .530 BC.
A 300gr .338 bullet will be in the mid to high .700 BC ( 300 SMK is .768 BC).
So with a 150gr .277 dia bullet @ 3000 ft/sec drop at 400yrds would be 18.7 "
Wind drift @ 400 yrds would be 10.2"
And with a 300gr .338 dia. bullet @ 3000 ft/sec drop at 400yrds is 16.9"
and wind drift is 6.4"
At 1000yrds the .277 150 gr @3000 ft/sec mv drops 275.7" and drift is 79.7"
The .338 300 gr @ 3000 ft/sec mv drops.217.0" and drift is 45.4"
So compairing the two is not very fair to the 270 .
The point to my reply is that with weight comes BC and ( the higher the weigh in
a given dia. the BC will go up as long as it is the same basic shape ( Not spitzer to
Round nose ).
This is The reason that most long range shooters try to get the Highest BC and velocity
there rifle is capable of and weight is the key to higher BC's
Just my point of view
J E CUSTOM