Calculating bullet drop

[Electronrider]

How do I go about calculating bullet drop in a new load? I know my FPS, and bullet weight, and BC. Is there a formula for this?

 

[nucone]

You will need to know the ballistic coefficient for your bullet. For formula, check your reloading manual or the external ballistics tables. Alternatively, use this calculator;

Handloads.Com Ballistic Calculator

 

[tenring]

www.eskimo.com/~jbm/calculations/traj/traj.html - Similar Sites and Reviews | Xmarks

 

[Hop]

I use the Strelok app for Android phones. It gets you really close. Don't tell the Appleseed instructors that this is almost better than a log book!

https://play.google.com/store/apps/details?id=com.borisov.strelok&hl=en

 

[Electronrider]

Holy cow! These things drop like rocks!

Is this why a lot of people will sight in for 200yds and go from there?

 

[Leo]

For almost any modern centerfire rifle, the bullet compensation is pretty close to the military rule of thumb. From a 100 yard zero, compensate 1 to 1.5 MOA at 200 yards. add 2.5 to 3MOA to that setting for a 300 yard target. Add 7MOA to that setting for 500 yards. Add 4 more MOA to take you out to 600 yards. Of course there are very high velocity and High B.C. bullets that shoot flatter, but these compensations will get you close enough to hit the target in most applications.

Good Luck, and have fun

 

[Leo]

Holy cow! These things drop like rocks!

Is this why a lot of people will sight in for 200yds and go from there?

Things get really interesting after 5 or 600 yards. For example, the .308 is really marginal past 800 yards. PALMA competition uses that cartridge at 800-900-and 1000 yards. To hit the target at 1000 yards, the bullet has to be 326 inches above the line of sight at 650 to 700 yards. So if a 6 foot man was standing at 700 yards in front of the 1000 yard target, and you pulled the trigger, the bullet would fly 20 feet over his head before it hit the target he was standing in a way that blocked the target from you view.


Even though I have recorded very good scores on the 1000 yard target, I have never found a volunteer to help me demonstrate the safety of standing 300 yards in front of a 1000 yard target.

 

[jwh20]

Holy cow! These things drop like rocks!

Is this why a lot of people will sight in for 200yds and go from there?

In fact bullets drop exactly like rocks! It's that old gravity thing. If you fire two bullets from two guns with the barrels parallel to the ground, both rounds would hit the ground at exactly the same time. I know you might think otherwise but that's just the physics of it. The faster one will travel a longer distance due to that d = ft ( distance = velocity * time) but both drop from the muzzle at the same acceleration of 9.8 m/s*s.

 

[BKExpress]

I use Strelok as well and it is very close to actual. You plug in the information and it computes your correction. And, it's free if you have an android phone. I think it's $10 if you have an iPhone. There are other ballistic calculators out there, but this is very good.

Good luck!

 

[kludge]

Holy cow! These things drop like rocks!

Is this why a lot of people will sight in for 200yds and go from there?

You never said what you're shooting, so I can't answer, but LOL@jwh20.

 

[Broom_jm]

For the PC, I use the free PointBlank software. It has a lot of options beyond the external ballistics calculations and you can print out the drop tables from it.

ER asked the question: "Is this why a lot of people will sight in for 200yds and go from there?"

Before the days of easily-adjusted external turrets, folks sighted in their big game rifles for a maximum point-blank range (PBR), based on the information you provided in the OP, along with a specific sight height. Let's say you're hunting deer and want to keep your bullets no more than 4" above or below line of sight, meaning where you aim with your scope. You feed the data into a ballistics calculator that will tell you what range to zero at, or how high to sight in at 100 yards.

These days, folks are a bit too obsessed with hitting the "X" every time. I hardly ever hit the exact spot I'm aiming at, when I'm shooting with a big game rifle. The exception is when I am shooting AT the zero range, which is almost never 100 yards, or an even increment of yardage. I suppose I could buy a scope that lets me zero at 100 and then adjust on it for different yardages, but I can't begin to think of why I'd do that. It won't improve my group sizes; it will only move them to where I was aiming. It also won't improve my on-game shooting, since I'm already dialed in perfectly for that. All a scope like that would do is complicate the process unnecessarily.

Now, for long-range competition, or for shooting much smaller targets, at known (lasered) distances, an adjustable scope might be just the thing. Such were not readily available back when I was shooting ground squirrels out in California, but that didn't prevent us from sending a goodly number of them to that big dog-town in the sky. A 4" maximum PBR, combined with knowing your load and how to use Kentucky windage, made for a lot of fun shooting. Some might say these fancy new scopes take all the fun out of it.

 

[IUOE]

For the PC, I use the free PointBlank software. It has a lot of options beyond the external ballistics calculations and you can print out the drop tables from it.

ER asked the question: "Is this why a lot of people will sight in for 200yds and go from there?"

Before the days of easily-adjusted external turrets, folks sighted in their big game rifles for a maximum point-blank range (PBR), based on the information you provided in the OP, along with a specific sight height. Let's say you're hunting deer and want to keep your bullets no more than 4" above or below line of sight, meaning where you aim with your scope. You feed the data into a ballistics calculator that will tell you what range to zero at, or how high to sight in at 100 yards.

These days, folks are a bit too obsessed with hitting the "X" every time. I hardly ever hit the exact spot I'm aiming at, when I'm shooting with a big game rifle. The exception is when I am shooting AT the zero range, which is almost never 100 yards, or an even increment of yardage. I suppose I could buy a scope that lets me zero at 100 and then adjust on it for different yardages, but I can't begin to think of why I'd do that. It won't improve my group sizes; it will only move them to where I was aiming. It also won't improve my on-game shooting, since I'm already dialed in perfectly for that. All a scope like that would do is complicate the process unnecessarily.

Now, for long-range competition, or for shooting much smaller targets, at known (lasered) distances, an adjustable scope might be just the thing. Such were not readily available back when I was shooting ground squirrels out in California, but that didn't prevent us from sending a goodly number of them to that big dog-town in the sky. A 4" maximum PBR, combined with knowing your load and how to use Kentucky windage, made for a lot of fun shooting. Some might say these fancy new scopes take all the fun out of it.

That's how I set up all of my deer guns.

ShootersCalculator.com

 

[sloughfoot]

I am guilty of wanting all my shots to hit in the X-Ring. I shoot a lot of high power. I have never used a computer to calculate bullet drop, etc.

Like Leo, I use standard come-ups that all HP shooters utilize. They rarely change once I get a solid zero for each yard line. Data is kept in a data book for each rifle.