The featured image above shows one of ALCO’s .308 Ultra-Low Drag (ULD) Steel Tip airgun slugs. The short video below demonstrates loading that projectile into an AirForce Texan. You’ll notice the slug is loaded directly into the breech rather than through a magazine. The Texan is simply one example of a single-feed big bore PCP air rifle that allows longer, high-performance projectiles to be loaded directly into the chamber. Many other single-feed platforms are designed in a similar manner.
One of the most common questions we receive at ALCO is:
“Will this bullet fit my airgun?”
It’s an important question—and one that involves much more than caliber alone.
That isn’t by accident.
At ALCO, we don’t start with the question, “Will it fit the magazine?” We start with, “How do we build the best-performing projectile possible?” From there, we engineer both magazine-compatible airgun slugs and proprietary Ultra-Low Drag (ULD) designs. Some of those advanced ULD projectiles require the additional loading length available in single-feed rifles to fully realize their aerodynamic advantages. That’s a design choice driven by performance—not magazine dimensions.
Our goal has always been the same:
Build big bore airgun slugs that deliver exceptional accuracy, ballistic efficiency, and dependable performance for both competition and hunting.
Understanding that philosophy helps shooters choose the projectile that best matches both their rifle and the way they intend to use it.
Understanding Compatibility
Many shooters assume that if a rifle is chambered for a particular caliber, every projectile of that caliber will fit.
Unfortunately, it’s not that simple.
There are two separate compatibility questions every shooter should answer.
First, will the projectile fit your bore correctly?
Second, will it fit your rifle’s loading system?
Knowing your rifle’s exact bore diameter is critical to selecting the proper projectile. At the same time, overall projectile length determines whether a slug can be used in a magazine or must be loaded directly into the breech.
A .357 airgun slug may be the correct diameter for the barrel but still be too long for the magazine.
Likewise, a .457 slug may chamber perfectly in one rifle while requiring single-feed loading in another.
Compatibility depends on much more than caliber alone. Bore diameter, projectile length, nose profile, chamber dimensions, magazine length, and the rifle’s loading system all work together to determine which projectile is the best choice.
Why Some Airgun Slugs Are Longer
Longer isn’t simply a design choice—it serves a purpose.
Many of ALCO’s proprietary airgun slugs are built around Ultra-Low Drag (ULD) principles. By increasing projectile length while maintaining proper weight distribution, we can create a more efficient aerodynamic profile that reduces drag, improves stability, and retains energy farther downrange.
For hunters, that translates into greater retained energy and dependable terminal performance at extended distances.
For target shooters, it provides a projectile capable of maintaining accuracy well beyond traditional airgun ranges.
Those advantages often require additional overall length.
In magazine-fed rifles, magazine dimensions can become the limiting factor—not caliber.
That’s why ALCO engineers both magazine-compatible airgun slugs and longer ULD designs intended for single-feed platforms. Each projectile is developed for a specific purpose rather than forcing one design to fit every rifle.
Magazine-Fed vs. Single-Feed
Magazine-fed rifles offer the convenience of fast follow-up shots.
Single-feed rifles remove magazine length as a design limitation, allowing longer projectiles with highly efficient aerodynamic profiles.
Many long-range shooters actually prefer single-feeding because it gives them access to projectile designs that simply cannot be optimized within the physical dimensions of a magazine.
Neither loading system defines performance on its own.
What matters is selecting the projectile that best matches your rifle and your intended use.
Why Manufacturer Specifications Can Be Difficult
One challenge facing today’s big bore PCP airgun shooters is that many manufacturers simply do not publish the critical dimensions needed to determine projectile compatibility. While caliber is almost always listed, knowing your rifle’s exact bore diameter is equally important. Maximum magazine length, chamber length, and allowable overall projectile length are also frequently omitted from product literature.
Without those specifications, it can be difficult to know whether a particular airgun slug is intended for magazine-fed or single-feed use. In many cases, that information simply isn’t available, and contacting the manufacturer doesn’t always provide clear answers.
At ALCO, we continue to evaluate as many rifle platforms as possible so we can provide compatibility information based on actual measurements, firsthand testing, and real-world shooting experience whenever possible.
Don’t Guess—Ask
One thing we’ve learned over the years is that every rifle deserves individual consideration.
Two rifles with the same caliber may not necessarily share the same bore dimensions, chamber dimensions, or magazine length.
Rather than guessing, we’d rather answer your questions before you place an order.
If we know your rifle, we’ll tell you what we’ve tested.
If we haven’t tested it, we’ll tell you that too.
Honest information helps shooters make better decisions, and helping you select the correct projectile is always better than discovering a compatibility issue after your order arrives.
Built to Help Every Gun Shoot Better
At ALCO, our goal has never been to simply manufacture projectiles.
We design precision airgun slugs and precision rifle bullets to help shooters get the very best performance from their equipment.
That means considering far more than weight and ballistic coefficient.
It means understanding how a projectile fits, feeds, flies, and performs in the rifle it was engineered to shoot.
Every rifle is a little different.
Every shooter has different goals.
At ALCO, we believe the best projectile is the one engineered for your rifle—not one forced to fit every rifle.
Whether we’re engineering an Ultra-Low Drag (ULD) projectile or a magazine-compatible design, every ALCO airgun slug is purpose-built to maximize performance for competition and hunting. The loading system never drives the design—the intended performance does.
If you’re ever unsure whether one of our projectiles will fit your airgun, give us a call.
We’d much rather help you choose the right projectile the first time than have you order the wrong one.
Learn. Shoot. Improve.
Every ALCO Bullet Talk article is written to help shooters better understand projectile design, long-range performance, and big bore PCP airgun technology.
Explore more articles on our All About Bullets blog, and if you have a question you’d like us to cover in a future Bullet Talk, let us know.
To Make Every Gun Shoot Better.
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.
.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.
.357 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.
Built to Compete. Proven to Hunt.