ALCO Bullet Talk #9
What the Number Can — and Can’t — Tell You About an Airgun Slug
Bullet shape has a purpose. A round nose, hollow point, and streamlined ULD tipped design may look very different because each was engineered with a particular job in mind. Those differences in shape also affect how efficiently a projectile moves through the air—and that’s where ballistic coefficient comes into the conversation.
If you shoot big bore airguns, you’ve probably looked for the ballistic coefficient of an airgun slug. We understand why. BC gives you a useful number for comparing projectiles, estimating trajectory, and getting an idea of how efficiently a slug may travel downrange.
But BC is only one part of the story.
At ALCO, ballistic coefficient matters. But we don’t design a bullet simply to achieve an impressive number on paper. We consider the entire projectile—its shape, weight, intended use, accuracy, flight characteristics, and performance on impact.
We design the entire projectile to perform.
So what can that BC number actually tell you about an airgun slug—and just as importantly, what can’t it tell you?
So, What Does BC Really Tell You?
Without getting into the math, think of ballistic coefficient as a way of describing how efficiently a projectile moves through the air.
Once a slug leaves the barrel, air immediately begins working against it. A more ballistically efficient projectile generally retains its velocity better and is less affected by drag as it travels downrange.
That becomes increasingly important as distance grows.
But here’s the distinction that’s easy to miss:
BC describes a projectile’s efficiency in flight. It doesn’t tell you whether that projectile will shoot accurately from your air rifle.
Those are two different questions.
A Bigger Number Doesn’t Automatically Mean a Better Slug
It’s tempting to compare two airgun slugs, look at their BC numbers, and choose the higher one.
If only it were that simple.
A projectile still has to work with the rifle launching it. Your barrel, twist rate, power, velocity and the projectile itself all become part of the system.
A beautifully streamlined slug with excellent ballistic potential isn’t much help if your particular airgun can’t stabilize it consistently.
That’s why we encourage shooters to pay attention to what happens on the target, not just what’s printed in the specifications.
The best-performing airgun slug is the one that works with your rifle and your intended use.
Weight Is Only Part of the Story
Another common assumption is that a heavier slug automatically has a better ballistic coefficient.
Weight can contribute to ballistic efficiency, but projectile shape matters tremendously.
Two slugs of the same caliber—and even relatively similar weights—can behave differently in flight because their designs are different.
Nose profile, projectile length, diameter, bearing surface, tip design and base configuration can all influence how a projectile travels through the air.
This is an important part of the thinking behind ALCO’s Ultra-Low Drag (ULD) airgun slugs.
Rather than simply adding more lead to make a projectile heavier, we can use the entire geometry of the slug to improve its efficiency. Our tipped ULD designs are engineered to create a streamlined projectile that manages airflow and drag while remaining stable in flight.
That’s engineering you can’t see by looking at a BC number alone.
Different Shapes. Different Jobs.
Look again at the different bullet profiles shown at the beginning of this article. The round nose, hollow point, and ULD tipped designs aren’t simply different ways to make a projectile—they were designed to do different jobs. A hollow point may place greater emphasis on terminal performance, while a streamlined ULD profile is designed to improve efficiency in flight. Weight, length, nose profile, base design, and intended use all play a role in the finished projectile. That’s why comparing bullets by BC alone can miss an important part of the picture. The best bullet isn’t necessarily the one with the highest BC. It’s the one designed to perform the job you’re asking it to do.
Why BC Still Matters
None of this means ballistic coefficient isn’t important.
It is.
BC gives you useful information about what happens after the projectile leaves the muzzle. As shooting distance increases, ballistic efficiency becomes increasingly valuable because the projectile has more time in flight for drag and wind to affect it.
A more efficient design can help retain velocity and energy and can reduce the effects of wind compared with a less efficient projectile under similar conditions.
For a big bore airgun shooter, that’s useful information.
It just isn’t the only information that matters.
How ALCO Looks at Projectile Performance
When we design an ALCO big bore airgun slug, we aren’t trying to create a projectile that simply produces the most impressive BC number.
Every ALCO bullet is engineered around three performance goals: uncompromising accuracy, superior ballistic efficiency in flight, and dependable terminal ballistics on impact.
Those three things have to work together.
A high ballistic coefficient can’t make up for poor accuracy. Excellent accuracy at the muzzle doesn’t mean much if the projectile becomes unstable farther downrange. And for a hunting projectile, neither matters if the bullet doesn’t perform properly when it reaches the animal.
That’s why we look at the projectile as a complete system rather than chasing one specification.
The Number Is a Starting Point
Use ballistic coefficient. Put it into your ballistic calculator. Compare projectiles. Learn what it tells you about trajectory, velocity retention and wind.
Then take your airgun to the range.
Shoot the slug at the distances you actually intend to use it. Learn your rifle. Learn your zero. Watch your groups and record your results.
Because ultimately:
BC tells you something about the projectile’s efficiency in flight. Your target tells you whether the entire system is working.
And when it comes to choosing the right airgun slug, you want both.
Explore the ALCO Airgun Slug Lineup
The engineering principles discussed in this article are applied throughout the ALCO airgun slug lineup. Whether you’re looking for long-range target performance, dependable hunting performance, or magazine-compatible airgun slugs, every ALCO projectile is engineered for a specific purpose.
Built to Compete. Proven to Hunt.
.308 Airgun– Ultra-Low Drag (ULD) steel-tip airgun slugs engineered for maximum ballistic efficiency, long-range accuracy, and hunting performance in single-feed rifles.
.338 Airgun Series – Proprietary Ultra-Low Drag (ULD) steel-tip airgun slugs engineered specifically for custom, single-feed .338 caliber PCP air rifles, delivering exceptional long-range accuracy, aerodynamic efficiency, and hunting performance.
.357 Airgun and ORION Series – Ultra-Low Drag (ULD) steel-tip airgun slugs available in both magazine-compatible and single-feed configurations for exceptional competition and hunting performance.
.452 TETON Series – Ultra-Low Drag (ULD) aluminum-tip airgun slugs engineered for maximum ballistic efficiency, retained energy, and long-range accuracy.
.457 LANCER and TETON Series – Ultra-Low Drag (ULD) aluminum-tip airgun slugs developed for maximum ballistic efficiency, retained energy, and long-range precision.
.457 Slug Series – Magazine-compatible, precision-swaged 100% soft lead airgun slugs developed for outstanding accuracy and dependable hunting performance.
.510 LANCER and TETON Series – Ultra-Low Drag (ULD) aluminum-tip airgun slugs engineered for hunters and long-range shooters seeking maximum ballistic efficiency and retained energy.
.510 Slug Series – Magazine-compatible, precision-swaged 100% soft lead airgun slugs available in hollow point, round nose/hollow back, and Slugger configurations for exceptional accuracy and dependable hunting performance.