Question about bullet drops

[Howa1500]

Hello all, I am trying to understand how bullet drops work. Below is the range and elevation of my 300 Win Mag. Can someone explain to me why I only have to dial 1.8 clicks at 450 yards and that compensates for 29 inches of bullet drop (28.85 to be exact)? I'm using a 200 yard zero. Full ballistic table is here.

Range	Elevation MRAD
Yards	MIL
50	- .2
100	- .4
150	- .2
200	0
250	.3
300	.6
350	1
400	1.4
450	1.8
500	2.2
550	2.7
600	3.2

 

[chromatica]

An object falls a distance given by 1/2 g*t^2 (g t squared) where g is the acceleration of gravity and t is time in seconds. You have built up a table of distances, each separated by 50 yards. The bullet passes the first horizontal interval (0-50 yards) quickly. It picks up some downward velocity so it is falling faster by the time it enters the second interval (from 50-100 yards). Also it takes a little longer for it to travel that second interval. These two effects compound at each of the intervals meaning the vertical drop for each interval increases for each of the intervals you have laid out. Print out your table using inches for the second column and this pattern will become more clear.

 

[Howa1500]

Thanks for your reply, I understand this part but what I don't understand is for example how 1.8 MILs compensates for 29 inches of drop at 450 yards. I was told each click (1/10MIL) moves my reticle .36 of an inch at 100 yards. So doesn't 18 clicks only move my scope up 6.48 inches and not the 29 inches that I need?

 

[Krogen]

Thanks for your reply, I understand this part but what I don't understand is for example how 1.8 MILs compensates for 29 inches of drop at 450 yards. I was told each click (1/10MIL) moves my reticle .36 of an inch at 100 yards. So doesn't 18 clicks only move my scope up 6.48 inches and not the 29 inches that I need?

The 1/10 mil click is 0.36" at 100 yards. It is proportionally greater at 450 yards. 18 * 0.36 * 450 / 100 = 29.16"

 

[Howa1500]

ah right so it proportionally increases. That set off a light bulb in my head, I think I get it now. So I can trust my dial table, thats what I call it, idk what you guys call it

 

[J_idaho]

3.6” per mil
1.8mil X 3.6” at a 100 yards = 6.48” convert your yardage to moa 100yards=1moa 200 yards =2moa 450=4.5moa
4.5x6.48=29.16
this is not perfect math as I’m rounding everything to inch’s because that’s how my brain works.

 

[Ned Ludd]

The scope adjustment is an angular measurement. As you realized, the arc subtended by a given angle is what we estimate as group size, or linear distance at the target face, and it increases proportionally to distance. Although the bullet trajectory is a parabola, scope adjustments use angular measurement.

 

[Shifty6br]

An easy way....
1 mil = 3.6@ 100
1 mil = 36" @1000
keeping 3.6 as a constant therefore..

At 250yds 1mil = 2.5 x 3.6 = 9"
so at 250 yds 1 mil equals 9" therefore 1/10th or 1 "click" if you will, equals .9" at 250 yds. (9÷10)

Another example:

At 778 yds. The equation I would use is.

7.78 × 3.6 (constant) = 28.098" or 28"
So one mile at 778yds = 28".
1/10 or one "click" at 778yds = 2.8" (28 ÷10)


So in your case...

450 yds.
1 mil at 450 yds = 16.2" (4.5×3.6)
So knowing that at 450 yds 1 mil equals 16.2 inches and your ballistics call for 1.8 mil correction (not 1.8 clicks) you are dropping 29.16" at 400yds from a 200yd zero.
16.2 × 1.8 = 29.16

Hopefully you see the pattern in the past few examples of conversion 250 yds =2 5, 777yds = 7.78 and your example 450yds = 4.5. Take those decimal conversions x 3.6 to find your value at any distance. So another example of 882 yds I would take 8.82 x3.6 for a 1 mil value of (31.752) or 31.8" or 32" rounded per mil and 1/10 or (click) eqauling 3.18" or 3.2" rounded.

Easiest to remember in mils and not so much "clicks". 1 mil equals 1 mil a half is a half and everything else in between is 1/10.

For ranging with mils if you know your target size. 27.78 or (1000÷36) is the constant value used for ranging. So for example I want to range a 12" target, in my reticle I am seeing .5 or a half mil from top to bottom (or side to side). So the algorithm goes, starting with my constant 27.78 x 12 (target size) = 333. So now 333 will be my new constant FOR A 12" TARGET.
333 ÷ mils read or in this case 333 ÷ .5 = 666
So at .5 mils read in retucle the 12" target is at 666yds.

This is the method I use trying to keep things as simple as possible.

Hope this helps..

 

[Howa1500]

@Ned Ludd @Shifty6br @J_idaho thank you so much for your replies. I understand it now, that it's an angular measurement and not a linear measurement. This has really helped me. I mainly only do hunting so this has given me confidence in trusting my dialling. I got a chrono and I'm going to try and get an accurate ballistic chart. Thank you so much for teaching me guys.