I AM SHOOTING IN MY WIN MOD. 70 270. 140 GR. AccuBond, MY LOAD IS 52 GRS 4831SC @ 2800 FPS WITH BC OF 0.496. I WOULD LIKE TO ZERO @100 YRDS. CAN ANYONE TELL ME THE BULLET DROP @ 200,300, 400 AND 500 YRDS THANK YOU IN ADVANCE.
Oysterboy, If you are going to be shooting those longer ranges, why sightin for 100 yards? A 3.5 inch high setting at a 100 will allow you to shoot out to 300 with mimimual holdover, and no cranking in min of elevation. My elk rifles are all sighted in with a three hundred zero, which gives me a high hold out to 400. Good luck
When using a ballistics calculator, remember to include your two shot group size into the calculation.
in other words, when you see the number for 100 yd trajectory, ADD 1/2 your group size.
So, if you have a 2MOA rifle, you would add 1" at the 100 yd range, 2 inches at the 200 yds and so on
when you get to the drop BELOW the Zero yardage, SUBTRACT those amounts.
Zero at 300 yds:
at 100 yds, ADD 0.5 X 1 to the calculated trajectory
at 200 yds, ADD 0.5 X 2 to the calculated trajectory
at 400 yds, SUBTRACT 0.5 X 4 FROM the calculated trajectory
doing it this way, you KNOW you are inside those numbers.
Doing this removes the fantasy of being able to know where you are hitting at longer distances.
Imagine it this way.
JBM tells you at 400 yds, you will be 8 inches below point of aim. You have a 1.0" accurate rifle.
at 400 yds, your bullet can be anywhere from 6" low to 10" low. and that is if you are holding PERFECTLY.
I always use 2" group size as I KNOW my rifle is capable of much less but sometimes using certain rounds, they open a bit... but never more than 2"
So, what I do, I set the calculator to use the PBR as the ZERO range, then adjust my Kill Zone Size on the calculator down to where my HIGHEST point inside the zero range is never more than 1/2 of what I want my kill zone to be. (8" for deer, 12" for elk, 16" for moose)
just for an example: So for Deer, my 2" group size, JBM says my highest point is at 150 yds and 2.5" above the POA, I ADD 1.5" to the height, and KNOW my bullet will NEVER be above the 4" kill zone area, so inside my PBR, I "Point and Shoot" at CENTER chest.
at the other end, let's say JBM says my Zero for PBR is 245yds, and at 300 yds, my bullet drops 1" BELOW line of sight, I have to SUBTRACT 3 inches, giving me a max drop of 4"
So using that example, we can see that with my theoretical setup, I can "Point and Shoot" center chest at a deer out to 300 yds, and I KNOW my bullet will be INSIDE the kill zone.
if you fail to add/subtract those amounts, you may miss your game or worse, wound it and not understand why.
This is one of the reasons long range killing bothers me, as so many LR hunters don't take into account the lack of perfect accuracy of their rifles when they do the calculations.
for an interesting experiment, change up one parameter at a time and see how it effects the long range impact zone.
(Play with the 45/70 and see just how FLAT it can shoot out to 125 yds, or the 30-30 with Spitzers out to 250 yds)
Remember, a 1MOA rifle, at 600 yds can potentially be 6 inches outside your zone... 3 up and 3 down.
Then there is the issue of accurately guestimating the distance... a Laser Range Finder is MANDATORY.
