The numbers I stated are correct.
First I was reading "Hunter's Guide To Long Range Shooting" by Wayne van Zwoll. I read about what he had to say, then looked at the charts he has in the book on trajectories. Page 229, 338-378 Weatherby Mag, Weatherby 225 Barnes X, MV 3180, Arch in Inches, 100 yards "0", 200 yards "+3.1", 300 yards "+3.8", 400 Yards "0".
So I went and bought a Weatherby Accumark in 338-378. I load Nosler 225gr Accubonds. My loads crony at 3210fps. I sighted in at 100 yards dead on. I moved my targets out to 200 and 300 yards. I was shooting high, but still well within my 9" circle (the size of the kill zone on a Moose or Caribou). On out at 400 yards they are back down into the middle of the circle.
So what was printed in the book is pretty close to what I am doing. My loads are 30fps faster, but my trajectories are pretty close to the factory loads. Right where I think they should be. I don't care what your computer and ballistics charts say, what I stated are in the field facts.
Something really doesn’t compute here.
Things we know:
225g AccuBond, BC .550, 3210fps, 400 yard zero, first crossover point claimed to be at 100 yards
Things we assume:
1.5” Scope height, 500 feet altitude, 70 Fahrenheit
Things we calculate:
First crossover point = ~18 yards, not 100 yards. Slowing the bullet down brings it in closer, speeding it up to 4500fps pushes it out to about 37 yards. Still a very long way from 100.
Raising the BC of the bullet doesn’t work – at .800 the first crossover is only pushed out to 20 yards. A BC of 5.0 only pushes it out to 22 yards or so.
Since those don’t work, let’s raise the scope. Nope, a scope sitting 6” above the bore only pushes the first crossover out to about 74 yards.
Well, this works – mount the scope 6” high and push the bullet to 3750fps. So does 3210fps with a scope height of 8.3”.
Leaving the centerline of the scope at 1.5” above the centerline of the bore also works, you just need to push the bullet to 7500fps, give or take...
Nosler’s 6th Edition basically agrees with all three of my ballistic calculators – a 225g .338” AccuBond (BC .550) at 3200fps with a 400 yard zero is about :
5.1” high at 100 yards. Nosler 6th
5.0” high at 100 yards. Point Blank (free at
www.huntingnut.com)
5.1” high at 100 yards. iSnipe (iPhone app)
5.1” high at 100 yards. Ballistic (iPhone app)
Running the ballistics for a 225g Barnes ‘X’, BC .482, at 3180fps, 400 yard zero, yields a first crossover point of ... about 18 yards. Don’t know what Wayne was smoking, but his figures don’t match Nosler’s, not by a mile. (Well, OK, not by 82 yards...) Nor do they match ANY other set of published ballistic charts that I can find, not even close.
In fact, here are calculated numbers (from Point Bank) for the Barnes 225g ‘X’ @ 3180fps:
+5.3” @ 100
+8.2” @ 200
+6.6” @ 300
+/- 0.00” @ 400
These numbers match up well with those from Nosler using 3200fps and the 225g AccuBond:
+5.1” @ 100
+8.0” @ 200
+6.3” @ 300
+/- 0.00” @ 400
It would be nice to have a rifle that shot a .338” 225g bullet as flat as Wayne claims, but unless you’re shooting on the moon it just isn’t going to happen.
I think you need to recheck your “field facts”.