If you are someone who routinely shoots past 200 yards with a rifle, it would be quite helpful to know how to build your own ballistics chart/D.O.P.E. chart. By doing so, you can adjust your scope to have the cross hair line up with the point of impact at any given distance.
In a pinch, if you have a Mil-Dot reticle, you can use the Mil-Dot lines to adjust the aim. The first choice is more accurate if done correctly. The second option is a lot quicker, but a much less precise method.
What You Need
To create the ballistics chart, you need some tools and some information.
(Yes, there is math. No, it isn’t difficult math.)
Where to Start
The first place to start is with the information provided by the factory. This does not matter if you are shooting reloads or factory-built ammo.
There will be some slight differences depending on which course you take there, but the factory information is always the starting point. Some factories even provide very solid ballistics calculators and they should be leaned on heavily.
I shoot a lot of .270 Winchester as hunting ammo. As such, I have a ballistic chart for that round when shot from my rifle, with hand loads.
In order to build this chart, I need to know the ballistic coefficient of the bullet, the velocity my rifle shoots the bullets at, the weight of the projectile and how consistent the velocity is. Here’s what the factory info tells me:
- Bullet: Hornady SST #27352
- Weight of the projectile: 140 grains
- Ballistic coefficient: G1 BC .495
- Powder: H414
At just over 49 grains of powder, I have a strong accuracy node despite being far from maximum pressure or velocity. When I make precision loads my ES (Extreme Spread) is about 10 fps, confirmed with my Magneto chronograph.
From my rifle, this translates to 2780-2790 fps. If you are using factory ammo, (and do not have a chronograph) they give their best guess on the side of the box.
You will need to determine the length of barrel used in their test and calculate approximate gain or loss from your barrel length.
When that rough number is obtained, a basic chart can be made to test versus known distance targets.
Pick your ballistics calculator of choice. I like both options from Hornady found here. Note the 4DOF is more designed for longer distance and to provide more advanced calculations with input from a Kestrel. Well beyond the scope of this article.
Key information to input:
- Maximum range – 500 yards. With this rifle, I won’t normally harvest deer past 400 yards.
- Interval – I set this at 50 yards because it makes things more precise and I am only looking at a few more data points.
- Ballistic coefficient – Factory G1 value of .495 – for longer distances, G7 values tend to work better.
- Velocity – As I know my ES is 10 or less, I split the difference with 2785 fps.
- Bullet weight – Factory value of 140 grains.
- Zero – I zero my rifle at 200 yards. This choice provides no need to adjust on a deer out to 250 yards as my rise or drop is never more than 3.1” within than range.
- Optic height – Measure this yourself, but 1.5” is standard unless you have a scope riser or an optic larger than 50 mm.
An Example Ballistics Chart
Here’s what my chart looks like:
As mentioned above, I do not use the ballistics chart for anything shorter than 250 yards. Considering this, I abbreviate that portion to make a more compact chart. Past 250 yards, each 50-yard mark is notated for easy extrapolation from know listed distances.
I include inches of drop and MILRADs for several reasons. Inches are intuitive and if I need to use the mildot markings or Kentucky windage, I have the information. If I have the time, my scope is in MILRADs and 1.5 MILRADs is 15 clicks.
The velocity chart is a reminder for expansion velocity. Hornady states minimum reliable expansion on this bullet is 2000 fps. This makes a 500-yard shot questionable for expansion; and thus, hunting.
The charts I use also incorporate wind drift, but that is a whole other topic. For this article, I focused solely on drop.
If you do not have a chronometer, the above would be the initial stage of your chart. The next step would be to do live fire confirmation, from a solid rest.
If your rifle is zeroed at 200, then your bullets should be 1.8” high on a target at 100 yards and 7.7 inches low at 300 yards. Shoot a three or five-shot group. The group average being plus or minus a half-inch is easily written off as user bobble or inconsistency of bullet velocity.
If your impacts differ significantly more than that, go back to the ballistics calculator. Fiddle with the velocity numbers to see if you can make the observed numbers work.
If the factory velocity is listed as 2900 fps and your rifle has a shorter barrel, it might give 2750-2650 fps. With a 200 yard zero, this will be noticed as higher impacts at 100 yards and lower impacts at 300 yards.
By dropping the velocity values by 50 fps a few times, the numbers should get closer to observed data. As the data gets closer, fine-tune with smaller velocity adjustments, then reprint your chart based on what matches real-world observations.
Congrats, you now have a custom ballistics chart for your bullet/rifle combination.
Have you ever created your own ballistics chart? Let us know any tips you have in the comments below!