Daily Bulletin » JBM Ballistics

$99 K31 Rifle Hits Steel Bison at 2240 Yards — with Iron Sights

Editor — Fri, 11 Jul 2025 11:30:09 +0000

Magnified 8X view looking down-range at bison (American buffalo) target.

Could You Hit a Steel Bison at 2240 Yards (1.27 miles) … with Iron Sights?

Impossible as that may seem, that’s exactly what Ernie Jimenez did some years back at the North Springs Shooting Range in Price, Utah (elevation 5,627′). Shooting a milsurp Swiss K31 rifle chambered for the 7.5×55 Swiss round, Jimenez placed four hits on a three-foot-high, bison-shaped steel target placed a staggering 2240 yards from the firing line. Not bad for a rifle which Jimenez acquired many years ago for just $99.00. Of course he did have plenty of misses along the way (and Ernie even managed to hit the plate shielding his camera).

This video is set to start half-way through, when the shooter starts making hits:

The whole process was recorded on video and posted on YouTube. The Long-Range Shooters of Utah say this is an official Guinness World Record for longest shot with iron sights. We can’t confirm that, but it still is an impressive feat. Jimenez had to compensate for a huge amount of bullet drop. His K31’s long-range military sights helped but he still had to aim well over the pink bison. To see how far that target is, watch the video at 14:30 — a camera at the firing line zooms all the way back until the bison is nothing but a tiny dot. The photo below show the target at 8X magnification, but it’s still barely visible.

Here’s the unmagnified, “naked-eye” view from the firing line. Can you see a pink buffalo at all?

Bullet Dropped Over 400 Feet along its Trajectory
To roughly gauge the bullet drop, we took a 7.5x55mm Swiss load from the Hodgdon Reloading Center. With max “book” load of H4350, a 168gr Sierra HPBT has a muzzle velocity of 2524 FPS. According to JBM Ballistics, that bullet will drop over 400 feet during its flight. That’s lot of hold-over! Assuming a 100-yard zero, 59° temp, and 5,600′ altitude, JBM calculates that the drop to 2250 yards is a stunning 210.9 MOA — that’s 4969.9 inches, or 414.15 feet!

In the first part of the video, shooter Ernie Jimenez talks about his hand-loads and his K31 rifle. Here is an example of the distinctive straight-pull K31 (Karabiner Model 1931). Image courtesy AIM Surplus.

Bird’s Eye View via Aerial Drone — Hitting Steel at 1122 Yards

Editor — Sat, 08 Feb 2025 06:25:12 +0000

Many of our readers have never had a chance to shoot much past 600 yards. How far away does a 1000-yard+ target really seem to the naked eye? Well this short video answers that question. Gorilla Ammo, the video’s producers, used a camera-carrying aerial drone to fly downrange from the firing line all the way out to 1122 yards (and back again). Watch the drone footage at 0:00-0:07 and especially 0:48-1:03. The “bird’s-eye view” really gives you a sense of the distance. The “fly-back” at 0:48-1:03 time-mark is what makes this video worth watching.

The video features prone shooting at steel targets placed at 750 and 1122 yards. We do apologize for the lame, “oh so serious” voice-over which attempts to make this rather ordinary range session seem like some kind of life-changing experience. (Frankly, you may just want to turn the sound off — it’s that annoying.) It’s really not that big a deal to hit steel at 750 yards with a quality AR-15, chambered in .223 Rem, shooting Sierra 77 grain MatchKings.

Hitting Steel at 1122 Yards with 2540 FPS Ammo Can Be Challenging
The 1122-yard hits are a bit more impressive. Gorilla Ammo lists a relatively sedate 2540 fps Muzzle Velocity for its .223 Rem 77gr SMK ammunition. According to JBM Ballistics, at 1125 yards, that 2540 fps load has 68.3 MOA of drop from a 100-yard zero (firing at sea level and 80° F ambient). Moreover the bullet goes trans-sonic around 750 yards (losing stability) and is traveling just 933 fps at impact. And the wind’s the killer — at 1125 yards, with this bullet/load, a mere 2 mph, full-value wind change can move the Point of Impact over three feet!

Dream Day for a Vintage Rifle — Iron Sights Hits at 2240 Yards

Editor — Fri, 23 Dec 2022 13:51:58 +0000

Magnified 8X view looking down-range at buffalo target.

Could You Hit a Steel Buffalo at 2240 Yards (1.27 miles) … with Iron Sights?

This video is set to start half-way through, when the shooter starts making hits:

Here’s the unmagnified, “naked-eye” view from the firing line. Can you see a pink buffalo at all?

Eye in the Sky — Drone View of 1122-Yard Shooting Session

Editor — Thu, 04 Jun 2020 08:30:22 +0000

Hitting Steel at 1122 Yards with 2540 FPS Ammo Can Be Challenging
The 1122-yard hits are a bit more impressive. Gorilla Ammo lists a relatively sedate 2540 fps Muzzle Velocity for its .223 Rem 77gr SMK ammunition. According to JBM Ballistics, at 1125 yards, that 2540 fps load has 68.3 MOA of drop from a 100-yard zero (firing at sea level and 80° F ambient). Morever the bullet goes trans-sonic around 750 yards (losing stability) and is traveling just 933 fps at impact. And the wind’s the killer — at 1125 yards, with this bullet/load, a mere 2 mph, full-value wind change can move the Point of Impact over three feet!

ELR with $99 Rifle — Hitting Steel at 2240 Yards with Iron Sights!

Editor — Sun, 31 May 2020 15:53:32 +0000

Magnified 8X view looking down-range at buffalo target.

Could You Hit a Steel Buffalo at 2240 Yards (1.27 miles) … with Iron Sights?

This video is set to start half-way through, when the shooter starts making hits:

Here’s the unmagnified, “naked-eye” view from the firing line. Can you see a pink buffalo at all?

Get Most Popular Ballistics App for iOS at Half Price

Editor — Thu, 04 May 2017 19:06:47 +0000

Need a top-notch Ballistics App for your iPhone, iPad, or iPod? Start with Ballistic AE, the number 1 (i.e. most installed) App for iOS systems. Ballistics AE (Advanced Edition) is the most popular iOS ballistics program for many good reasons. Full-featured and easy to use, Ballistics AE has been refined over many years, and it supplies rock-solid solutions derived from JBM Ballistics solver (created by James B. Millard). Unlike some other Apps, Ballistics AE is STABLE on iPhones (with various OS levels). What’s cool is that Ballistics AE is now on sale for $12.99.

We’ve used the Ballistic AE program on an iPhone 5S, iPhone 6, and iPad, and it performed well. Here are some of the features we liked:

1. Mirrors output from online version of JBM Ballistics we often use for initial calculations.
2. Controls are simple to use and (mostly) intuitive.
3. Handy comparison feature lets you compare ballistics for different projectiles side by side.
4. Advanced Wind Kit allows you to account for complex wind situations.
5. Projectile and BC Database is very comprehensive.
6. Software is regularly updated to match Apple OS changes.

Ballistic-AE for iPhone, iPad, iPod, $14.99 (Sale) | Ballistic for iPad, $14.99 (Sale)

Comprehensive Projectile Info and BCs
Ballistics AE has very complete data libraries. The program includes 5,000 projectiles, factory loads, military loads, and performance data points from leading manufacturers, military testing, and performance testing.

Ballistic Coefficient libraries include the latest commercial BC data, plus Applied Ballistics’ (Bryan Litz) custom G7 BCs, plus G7 military coefficients from Aberdeen Proving Grounds.

These Videos Explain How to Set Up and Use Ballistic AE:

Brain Teaser: Do You Know the Rule of the Square?

Editor — Tue, 17 Feb 2015 06:15:46 +0000

Horizontal Wind-Drift vs. Distance
OK, here’s a challenge question for you.
Let’s see if you get it right.

Q: If the wind is blowing 10 mph from 9 o’clock and if my horizontal wind deflection is 0.7 inches at 100 yards, what is the horizontal drift at 1000 yards?

You may be thinking, “Well, since the target is ten times more distant, the wind-drift should be around 7 inches, maybe a little more since the bullet will be slowing down.” That sounds reasonable, right?

WRONG.

As you move from near to far, the increase in lateral deflection (from a 90° crosswind) is (roughly speaking) a function of the square of the multiple of distance. If your target is two times farther away, you use the square of two, namely four. If your target is five times farther away, you use the square of five, or twenty-five. In this example, the increased wind drift (from 100 to 1000 yards) is at least 0.7″ times (10 X 10) — over 70 inches (give or take a few inches depending on bullet type). We call that the Rule of the Square. This Rule lets you make a quick approximation of the windage correction needed at any yardage.

Precision Shooting and the Rule of the Square
I was going through some back issues of Precision Shooting Magazine and found many references to the Rule of the Square. This made me curious — I wondered how well the Rule really stacked up against modern ballistics programs. Accordingly, I ran some examples through the JBM Ballistics Trajectory Calculator, one of the best web-based ballistics programs. To my surprise, the Rule of the Square does a pretty good job of describing things.

EXAMPLE ONE — .308 Win (100 to 400 Yards)
For a 168gr Sierra MK (.308), leaving the muzzle at 2700 fps, the JBM-predicted values* are as follows, with a 10 mph, 9 o’clock crosswind (at sea level, 65° F, Litz G7 BC):

Drift at 100: 0.8 MOA (0.8″)
Drift at 200: 1.6 MOA (3.3″)
Drift at 400: 3.4 MOA (14.4″)

Here you can see how the Rule of the Square works. The rule says our drift at 200 yards should be about FOUR times the drift at 100. It the example above, 0.8″ times 4 is 3.2″, pretty darn close to the JBM prediction of 3.3″. Quoting Precision Shooting: “Note that the deflections at 100 yards are typically a quarter of those at 200; lateral deflections increase as the square of the range”. Precision Shooting, June 2000, p. 16.

EXAMPLE TWO — .284 Win (100 to 1000 Yards)
For a .284 Win load, with the slippery Berger 180gr Target Hybrids, the Rule of the Square still works. Here we’ll input a 2750 fps velocity, Litz G7 BC, 10 mph, 9 o’clock crosswind, (same 65° temp at sea level). With these variables, JBM predicts:

Drift at 100: 0.5 MOA (0.5″)
Drift at 500: 2.5 MOA (13.3″)
Drift at 1000: 5.9 MOA (61.3″)

Again, even with a higher BC bullet, at 1000 yards we end up with something reasonably close to the 100-yard deflection (i.e. 0.5″) multiplied by (10×10), i.e. 50 inches. The Rule of the Square alerts you to the fact that the effects of crosswinds are MUCH greater at very long range. In this example, our JBM-calculated drift at 1000 is 61.3″ — that’s over 100 times the 100-yard lateral drift, even though the distance has only increased 10 times.

Note that, even with a 5 mph 90° sidewind, the “Rule of the Square” still applies. The 1000-yard lateral deflection in inches is still over 100 times the lateral deflection at 100 yards.

Why This All Matters (Even in the Age of Smartphones)
Now, some would say, “Why Should I Care About the Rule of the Square? My iPhone has a Ballistics App that does all my thinking for me”. Fair enough, but knowledge of this basic Rule of the Square enables a shooter to make an informed guess about necessary windage even without a come-up sheet, as long as he knows the distance AND can fire a sighter at 100 or 200 yards as a baseline.

For example, if I see empirically that I need 1″ windage correction at 100 yards, then I know that at 600 yards I need at least roughly (6 x 6 x 1″) or 36 total inches of drift correction, or 6 MOA. (To be precise, 1 MOA = 1.047″ at 100 yards). I can figure that out instantly, even without a ballistics chart, and even if my Smartphone’s battery is dead.

*Values shown are as displayed on the JBM-figured trajectory tables. The numbers can be slightly imprecise because JBM rounds off to one decimal place for both inches and MOA.

Over-Shooting the Berm — When a Mere 5 Degrees Can Be Deadly

Editor — Sun, 01 Feb 2015 12:22:43 +0000

In our Shooters’ Forum, there was an discussion about a range that was threatened with closure because rifle over-shoots were hitting a farm building over two miles from the firing line. One reader was skeptical of this, asking “how’s that possible — were these guys aiming at the stars?” Actually, you may be surprised. It doesn’t take much up-angle on a rifle to have a bullet land miles down-range. That’s why it’s so important that hunters and target shooters always orient their barrels in a safe direction (and angle). Shooters may not realize how much a small tilt of the barrel (above horizontal) can alter a bullet’s trajectory.

How many degrees of muzzle elevation do you think it would take to hit a barn at 3000 yards? Ten Degrees? Twenty Degrees? Actually the answer is much less — for a typical hunting cartridge, five to seven degrees of up-angle on the rifle is enough to create a trajectory that will have your bullet impacting at 3000 yards — that’s 1.7 miles away!

Five degrees isn’t much at all. Look at the diagram below. The angle actually displayed for the up-tilted rifle is a true 5.07 degrees (above horizontal). Using JBM Ballistics, we calculated 5.07° as the angle that would produce a 3000-yard impact with a 185gr .30-caliber bullet launched at 2850 fps MV. That would be a moderate “book load” for a .300 Win Mag deer rifle.

Here’s how we derived the angle value. Using Litz-derived BCs for a 185gr Berger Hunting VLD launched at 2850 fps, the drop at 3000 yards is 304.1 MOA (Minutes of Angle), assuming a 100-yard zero. This was calculated using a G7 BC with the JBM Ballistics Program. There are 60 MOA for each 1 degree of Angle. Thus, 304.1 MOA equals 5.068 degrees. So, that means that if you tilt up your muzzle just slightly over five degrees, your 185gr bullet (2850 fps MV) will impact 3000 yards down-range.

Figuring Trajectories with Different Bullets and MVs
If the bullet travels slower, or if you shoot a bullet with a lower BC, the angle elevation required for a 3000-yard impact goes up, but the principle is the same. Let’s say you have a 168gr HPBT MatchKing launched at 2750 fps MV from a .308 Winchester. (That’s a typical tactical load.) With a 100-yard zero, the total drop is 440.1 MOA, or 7.335 degrees. That’s more up-tilt than our example above, but seven degrees is still not that much, when you consider how a rifle might be handled during a negligent discharge. Think about a hunter getting into position for a prone shot. If careless, he could easily touch off the trigger with a muzzle up-angle of 10 degrees or more. Even when shooting from the bench, there is the possibility of discharging a rifle before the gun is leveled, sending the shot over the berm and, potentially, thousands of yards down-range.

Hopefully this article has shown folks that a very small amount of barrel elevation can make a huge difference in your bullet’s trajectory, and where it eventually lands. Nobody wants to put holes in a distant neighbor’s house, or worse yet, have the shot cause injury. Let’s go back to our original example of a 185gr bullet with a MV of 2850 fps. According to JBM, this projectile will still be traveling 687 fps at 3000 yards, with 193.7 ft/lbs of retained energy at that distance. That’s more than enough energy to be deadly.

How Altitude and Air Pressure Influence Ballistics

Editor — Sun, 19 Oct 2014 06:10:26 +0000

One of our readers asked “What effect does altitude have on the flight of a bullet?” The simplistic answer is that, at higher altitudes, the air is thinner (lower density), so there is less drag on the bullet. This means that the amount of bullet drop is less at any given flight distance from the muzzle. Since the force of gravity is essentially constant on the earth’s surface (for practical purposes), the bullet’s downward acceleration doesn’t change, but a bullet launched at a higher altitude is able to fly slightly farther (in the thinner air) for every increment of downward movement. Effectively, the bullet behaves as if it has a higher ballistic coefficient.

Forum member Milanuk explains that the key factor is not altitude, but rather air pressure. Milanuk writes:

“In basic terms, as your altitude increases, the density of the air the bullet must travel through decreases, thereby reducing the drag on the bullet. Generally, the higher the altitude, the less the bullet will drop. For example, I shoot at a couple ranges here in the Pacific Northwest. Both are at 1000′ ASL or less. I’ll need about 29-30 MOA to get from 100 yard to 1000 yards with a Berger 155gr VLD @ 2960fps. By contrast, in Raton, NM, located at 6600′ ASL, I’ll only need about 24-25 MOA to do the same. That’s a significant difference.

Note that it is the barometric pressure that really matters, not simply the nominal altitude. The barometric pressure will indicate the reduced pressure from a higher altitude, but it will also show you the pressure changes as a front moves in, etc. which can play havoc w/ your calculated come-ups. Most altimeters are simply barometers that read in feet instead of inches of mercury.”

As Milanuk states, it is NOT altitude per se, but the LOCAL barometric pressure (sometimes called “station pressure”) that is key. The two atmospheric conditions that most effect bullet flight are air temperature, and barometric pressure. Normally, humidity has a negligible effect.

It’s important to remember that the barometric pressure reported on the radio (or internet) may be stated as a sea level equivalency. So in Denver (at 6,000 feet amsl), if the local pressure is 24″, the radio will report the barometric pressure to be 30″. If you do high altitude shooting at long range, bring along a Kestral, or remember to mentally correct the radio station’s pressure, by 1″ per 1,000 feet.”

You can do your own experimental calculations using JBM Online Ballistics (free to use). Here is an extreme example, with two printouts (generated with Point Blank software), one showing bullet trajectory at sea level (0′ altitude) and one at 20,000 feet. For demonstration sake, we assigned a low 0.2 BC to the bullet, with a velocity of 3000 fps.

Trajectory of Bullet fired at Sea Level

Trajectory of Bullet fired at 20,000 feet

if you want to learn more about all aspects of External Ballistics, ExteriorBallistics.com provides a variety of useful resources. In particular, on that site, Section 3.1 of the Sierra Manual is reprinted, covering Effects of Altitude and Atmospheric Pressure on bullet flight.

G1 vs. G7 Ballistic Coefficients — What You Need to Know

Editor — Mon, 07 Jan 2013 07:40:23 +0000

The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You’ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn’t mean you should select a G1 value simply because it is higher.

Some readers are not quite sure about the difference between G1 and G7 models. One forum member wrote us: “I went on the JBM Ballistics website to use the web-based Trajectory Calculator and when I got to the part that gives you a choice to choose between G1 and G7 BC, I was stumped. What determines how, or which one to use?”

The simple answer to that is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.

G1 vs. G7 Ballistic Coefficients — Which Is Right for You?
G1 and G7 refer both refer to aerodynamic drag models based on particular “standard projectile” shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferrable for flat-based bullets, while G7 is ordinarily a “better fit” for longer, boat-tailed bullets.

Drag Models — G7 is better than G1 for Long-Range Bullets
Many ballistics programs still offer only the default G1 drag model. Bryan Litz, author of Applied Ballistics for Long Range Shooting, believes the G7 standard is preferrable for long-range, low-drag bullets: “Part of the reason there is so much ‘slop’ in advertised BCs is because they’re referenced to the G1 standard which is very speed sensitive. The G7 standard is more appropriate for long range bullets. Here’s the results of my testing on two low-drag, long-range boat-tail bullets, so you can see how the G1 and G7 Ballistic coefficients compare:

G1 BCs, averaged between 1500 fps and 3000 fps:
Berger 180 VLD: 0.659 lb/in²
JLK 180: 0.645 lb/in²

The reason the BC for the JLK is less is mostly because the meplat was significantly larger on the particular lot that I tested (0.075″ vs 0.059″; see attached drawings).

For bullets like these, it’s much better to use the G7 standard. The following BCs are referenced to the G7 standard, and are constant for all speeds.

G7 BCs:
Berger 180 VLD: 0.337 lb/in²
JLK 180: 0.330 lb/in²

Many modern ballistics programs, including the free online JBM Ballistics Program, are able to use BCs referenced to G7 standards. When available, these BCs are more appropriate for long range bullets, according to Bryan.

[Editor’s NOTE: BCs are normally reported simply as an 0.XXX number. The lb/in² tag applies to all BCs, but is commonly left off for simplicity.]