Home Forums Hunting & Shooting Ask The Gunwriters APRIL column--Advantages of High BC

THE ADVANTAGES OF HIGHER BALLISTIC COEFFICIENT

Today there seems to be considerable confusion over rifle bullets with higher ballistic coefficients. Part of this is natural, and goes way back to the days when rifles finally started becoming better than longbows, and then other advances in hunting rifles from smokeless powder onward: Hunters are naturally conservative, and many among us will always say, "Round balls worked just fine. There's no need for Minie bullets."

In fact, I've bounced back and forth over high-BC bullets over the decades, like many hunters who started back when telescopic sights weren't an assumed accessory a big game of even varmint rifle. But I started to get a glimmer in the 1970's, when as a young adult I could semi-afford to indulge my rifle-loony tendencies.

By age 21 I had a small, indiscriminate collection of hunting rifles, and a Lee Loader for a 7.62 Russian I no longer owned. I got rid of everything and bought a pair of Remington 700's in .243 and .270 Winchester, because 700's were then considered the most accurate factory rifles, then bought a genuine reloading press. In theory the .243 was for everything from prairie dogs to deer (back then the "dual purpose rifle" was a widely accepted concept) and the .270 for bigger game. In reality they both got used a lot on deer-sized game, partly because back then I was married to an enrolled member of one of eastern Montana's big Indian reservations, so could legally hunt like a tribal member. There was no closed season or limit, and my wife also had plenty of hungry relatives.

There was also plenty of open land for longer-range practice with my handloading experiments. Back then most hunters preferred the highest velocity possible for open-country hunting, because they wanted the flattest possible trajectory to compensate for range-estimation errors. Thus they often used relatively light bullets, because their handloading manuals showed the highest muzzle velocities with lighter bullets.

However, it didn't take long for my shooting to reveal that 105-grain Speer Hot-Cors in the .243 and 150-grain Hornady Spire Points in the .270 drifted less in the high-plains wind than lighter bullets, and still shot pretty damn flat. Luckily, both bullets also proved to be accurate.

I killed a lot of deer with both rifles at ranges from under 100 to over 400 yards, and in those pre-laser days 400 was considered about the practical limit. Both also worked well when I drew pronghorn tags off the rez (antelope were rare inside its borders), and the .270 worked all right on elk in Montana's western mountains, though I eventually started using 150-grain Nosler Partitions instead of the Hornadys. (I might not have if the 150 Spire Points had been Interlocks, but this was years before Hornady made that improvement. Back then a couple of the 150's came apart on deer, one a mule deer buck the size of a young elk, so I eventually sprung for a box of Partitions.)

This was also before chronographs became cheap enough for almost every handloader to afford one. I assumed my handloads got right around 3000 fps, at first because that's what my loading manuals suggested, but eventually I also became really technical and compared the "drop" of the 150-grain .270 load against the trajectory tables in the back of the Hornady manual. That rifle and load were so accurate that 3-shot groups averaged around an inch at 300 yards, something I later discovered was at least partly due to the secant-ogive Spire Points seating straighter than other bullets, apparently because they fit the seating-stem in my RCBS die better than the more common tangent-ogive bullets. The accuracy made range-checking the trajectory easier at longer ranges, and the numbers matched 3000 fps in the trajectory tables. Since the .243 load had the same trajectory and a very similar ballistic coefficient, I knew it had to be getting 3000 fps.

However, this assumption turned out to be wrong, because I was shooting at considerably higher elevation than sea level, the elevation the tables were based on. In 1979, after I'd been selling magazine articles for five years (including a few on hunting rifles) it became clear a chronograph would be required equipment. Before then the velocities in many articles were listed as "estimated," or came from handloading manuals. So I saved my money and bought a new Custom Chronograph, luckily at a gun-writer discount.

Unfortunately, it said both loads got 2800-2850 fps! The reason they shot so flat, of course, was the thin Montana air "changed" the ballistic coefficient of the bullets--another revelation. But eventually I discovered BC changes due to various factors. It is NOT a single, immutable number, as so many loading manuals and gun writer articles claimed (unless, of course, it's only calculated from a "form factor").
The pre-Interlock 150-grain Hornady Spire Point normally worked very well even at close range, as it did on a mule deer buck that field-dressed almost 250 pounds, because of the moderate muzzle velocity of 2850 fps.

At the time I ignored the great results I'd been getting in the field, including modest meat damage at closer ranges and less wind-drift at longer ranges. Instead I simply had to work up new loads with 100-grain and 130-grain bullets, in order to get at least 3000 fps on my new chronograph. Why? Because "everybody" knew muzzle velocity had to be at least 3000 fps for longer-range shooting.

However, in 1990 another BC revelation took place, one far more easily perceived in the field, when Nosler introduced their Ballistic Tip bullets in varmint calibers. By then I was publishing more firearms articles, and Nosler invited me on their annual prairie dog shoot, only a 3-hour drive from my home. Back then the standard prairie dog "battery" consisted of two rifles, one a .223 Remington for shooting out to 250-300 yards, and the other a .22-250, .220 Swift or .243 Winchester for shooting at longer ranges.

This was because varmint bullets BBT (Before Ballistic Tips) were either soft-points or hollow-points. Hollow-points were considered more accurate, but didn't expand as reliably as soft-points, unless the hole in the tip was pretty large. Neither had particularly good BC's, especially wide-cavity hollow-points, the reason the .223 was considered a 250-300 yard PD round, and faster rounds considered necessary beyond 300.

Nosler sent me a bunch of .224 50 and 55-grain Ballistic Tips for handloading, and I tried the 50's in my .223 Remington and the 55's in my .220 Swift. I was impressed by their 100-yard accuracy, especially in the .223, since it averaged a genuine half-inch for 5-shot groups.

But it only took a day of shooting prairie dogs to see another important difference in performance. Not only did the plastic tips cause the bullets to expand violently well beyond typical .223 range, but increased BC so much trajectory was a little flatter and wind-drift noticeably less. On the second day the Swift stayed in its case, because the .223 with 50-grain Ballistic Tips at 3500 fps basically matched previous Swift performance with soft or hollow-point bullets--and recoil was so much lighter I could spot my own shots through the scope.


BC differences are really obvious when shooting small varmints, such as prairie dogs.

Several ballistic improvements occurred during the next decade, including the appearance of laser rangefinders and, consequently, the first "ballistic" reticles and "dialing" scopes. I started experimenting with both, and by 2000 another interesting thing occurred: Hodgdon Li'l Gun finally put some real zip behind 40-grain bullets in the .22 Hornet.

I'd always been intrigued by the Hornet, but those belonging to friends didn't seem to provide much improvement over the .22 Winchester Rimfire Magnum. Now, however, there was a powder capable of getting close to the magic 3000 fps in the Hornet. I purchased a .22 Hornet carbine barrel for my Thompson-Center Contender Carbine, and 40-grain Nosler Ballistic Tips turned out to by far the best performers. The long plastic-tips wouldn't fit in the typical Hornet magazine, but made an amazing difference in the 21-inch Contender barrel, at 2900 fps turning the old Hornet into a much longer-ranged round.

Eventually, however, I grew weary of breaking the T/C open over and over again on prairie dog towns, often having to reload the chamber from awkward positions, so acquired a Ruger No. 1B. The falling-block action made unloading and reloading the chamber much easier, but accuracy was even batter, and in the 26-inch barrel the velocity of the load increased to 3000+ fps.

On relatively calm days the Hornet was now a consistent PD cartridge at 250-300 yards, just like the .223 was BBT, but with even lighter recoil, which made spotting my own shots through the scope even easier. This is an important virtue in prairie dog rounds, because otherwise you have to depend on somebody else standing next to you, watching where your shots supposedly land, and saying things like, "Um, a little high and right. Maybe more right than high...."

Due to higher-BC bullets, the Hornet was now my "short-range" PD round, just as the .223 had replaced the .220 Swift as my 300-500 yard round, long before faster twists and much heavier high-BC bullets extended the range of the .223 even more. Now, in the Hornet a little of this was due to the increased velocity possible with Li'l Gun--but the biggest factor was the much higher BC of plastic-tipped 40-grain bullets.

About a dozen years ago the then-editor of VARMINT HUNTER magazine, John Anderson, assigned me the pleasant task of field-testing every available varmint bullet. This proved to be impossible, because companies kept introducing new models, but I did get to shoot a bunch of 'em over a couple of years, partly because most of my varmint rifles tended to put all bullets in the same group at 100 yards. I could go on a PD shoot with several handloads and under the same field conditions, directly compare the performance of various loads.

Higher-BC plastic-tips proved to perform noticeably better than "standard" bullets in EVERY rifle, but the most obvious difference was in the Ruger Hornet. I hadn't loaded many standard Hornet bullets before, having quickly discovered how well 40-grain Ballistic Tips worked, but loaded several lighter, blunter bullets for the assignment, including some 30-grainers at 3400 fps.

There wasn't much noticeable difference between the lighter bullets and 40-grain plastic tips, whether made by Nosler, Hornady or Sierra, out to about 100 yards, but beyond that 40-grain plastic-tips started obviously pulling away, shooting flatter, drifting less in the wind, and expanding more violently. By 200 yards there was no comparison, and in fact in a typical PD breeze, the super-fast but relatively blunt 30-35 grain bullets were pretty useless at 200. The percentage of hits went way down, because even the slightest change in wind speed or direction drifted them considerably.

In fact, this greater susceptibility to wind-drift is the root of a common myth, that rifle bullets start to "destabilize" at longer ranges, the supposed reason rifles shoot proportionately larger groups at ranges beyond 100 yards. In fact the opposite is true: Rifle bullets stabilize because the spin impart by the rifling overcomes the air pressure on the nose of the bullet. As velocity drops, the nose-pressure drops as well, but spin decreases at a much slower rate--and the bullet becomes even more stable.

Instead, the reason many rifles shoot larger groups at longer ranges is wind, because wind-drift increases at about twice the rate of range. For instance, if a bullet drifts an inch at 200 yards in a given wind, it will drift about four inches at 400 yards. Now, if wind is absolutely steady, it won't affect group size at longer ranges--but it rarely is. Instead it tends to vary somewhat in angle and, especially, speed. The result is larger groups at longer ranges, even in relatively mild breezes under 5 mph. Which is exactly why my hit percentage with traditional blunt .22 Hornet bullets went way down beyond 100 yards, even though some started as much as 400 fps faster than 40-grain plastic-tips.

This was accompanied by a very noticeable difference in bullet expansion out at 200, because the typical blunt Hornet bullet had slowed way down. A good example is comparing the 35-grain Hornady V-Max started at 3300 fps with the 40-grain V-Max at 3000. In typical Montana PD conditions, at 200 yards the 35 is only going a little over 1800 fps, while the 40 is right around 2200 fps. This results in an enormous difference in wind-drift, with the 40 drifting only about half as much as the 35. (Oddly enough, there's less than an inch difference in bullet "drop." but as any PD shooters knows, wind is the big problem, especially as range increases.)

The same basic thing happened with other varmint bullets as well. Around that time the .204 Ruger cartridge became popular, with various companies offering bullets around 32 grains, capable of the even more magic 4000+ fps, but also bullets around 40 grains. Like the Ruger Hornet, my .204 also put various bullets into the same group at 100 yards, but it soon became obvious that despite the super-high muzzle velocity of lighter bullets, the 40's drifted less and expanded more violently beyond around 250 yards, especially in wind. This was true even if both 32's and 40's were plastic-tipped.

However, I didn't experience the same sort of revelation with big game bullets until a little later. While plastic tips also enhance the BC's of big game bullets, the jump isn't as large as with smaller-caliber varmint bullets, because in larger calibers the tip is a smaller percentage of the overall bullet shape. It wasn't until I went on a "test hunt" in New Zealand with Berger bullets that I really realized how high-BC bullets could affect big game shooting in the same way.

The Bergers didn't have plastic tips, but very sharp hollow-points, so tiny I couldn't insert the tip of a safety pin, but they still expanded violently, because the very thin jacket allowed the nose to collapse after the bullets penetrated 2-3 inches. During the trip several of us (including Walt Berger) shot lots of big game from feral goats to trophy red stags at ranges out to 550 yards. While some of the animals were taken with the .300 Winchester Magnum, a traditional long-range big game cartridge, most of the rest were taken with a couple .257 Roberts rifles (including Walt's pre-'64 Model 70 and my wife Eileen's New Ultra Light Arms) and my NULA .30-06.

Another cartridge, and in some ways the most impressive, was the .264 Winchester Magnum brought by my fellow gun writer Richard Mann. But I wondered about him some, when it turned out his handload with 140-grain Berger VLD's only got 2950 fps. From my own experience with the .264, I knew it could get 3200 fps with 140's in a 26-inch barrel. But the "slow" muzzle velocity turned out not to matter: The .264 proved the equal of the .300's at longer ranges, with a lot less recoil.

The reason? The 140-grain VLD had the highest BC of any of the bullets we used, whether the 115's used in the .257's (also at around 2950 fps), or the 185's used in the .300's at around 3050. As a result, the .264 bullet retained a little more velocity out at 500, and retained velocity is what makes bullets drift less in the wind, and expand. (One of the oddities I also noticed about VLD's on that trip is it didn't really matter much which bullet was used, as they ALL ripped up far more of the vital organs inside the chest than more conventional big game bullets, designed to retain more weight. But aside from higher long-range velocity aiding expansion, that's another story.)

One interesting aspects of being a gun writer is how "field testing" various products, such as new bullets, often forces you outside the comfortable box of assumptions collected over the years, some so universal they're hard to avoid. One of these is the assumption that a muzzle velocity of 3000+ fps is absolutely necessary for big game hunting at longer ranges, however they're defined. But a high BC results in more retained velocity out where the animals actually are, which is where a hunting bullet does its work. I am not a "long-range hunter," as the term is usually understood these days, having never pulled the trigger on a big game animal at much over 500 yards. But even at 300 yards there's no reason not to use higher-BC bullets, because they often end up going just as fast at 300 as conventional bullets started faster.

This is exactly why so many of my hunting loads developed over the past decade use high-BC bullets at muzzle velocities under 3000 fps, whether a 1-8 twist .223 with 75-grain plastic tips, or 6.5mm bullets in the 140+-grain class, 7mm's in the 160+ grain class, or 200-grain .30's. They recoil far less than pushing the same bullets at 3000+ fps, and don't burn up barrels as quickly, both factors allowing more practice without bothering you or your rifle.

At the same time they don't shoot up as much meat as 3000+ fps bullets at closer ranges, yet kill just as well at longer ranges, where they're often going a little faster than lighter bullets started faster. Plus, they drift less in the wind, and one thing I did notice many years ago, when working up loads for my new .243 and .270, was how the wind often blows in Montana.


With high-BC bullets, muzzle velocities over 3000 fps aren't necessary for longer shots.

This doesn't mean I've abandoned high muzzle velocity. One of my favorite hunting rifles is still the NULA .257 Weatherby Magnum Melvin Forbes built me almost 20 years ago, and the .257 "Roy" is all about light bullets screaming out the muzzle. But after considerable experimenting with various bullets, these days I've settled on the 100-grain Nosler E-Tip at 3550 fps, partly because its monolithic construction doesn't shred as much delicious pronghorn meat if I happen to encounter a buck at pretty close range. But it's also because the E-Tip has a little higher BC than other monolithics, so doesn't drift in the wind as much. (I also often use round-nosed or flat-tipped bullets in "woods cartridges" like the .30-30 and .358 Winchesters.)

But more and more often I'm happy to shoot relatively heavy-for-caliber, high-BC bullets at 2700-2850 fps, even when a longer shot is distinctly possible. They work just fine at short ranges, even cup-and-cores, but also work well way out there, because velocity doesn't vary as much over several hundred yards as with more conventional bullets. Instead of having extra powder perform the long-range work, ballistic coefficient gets the job.

Of course, "high ballistic coefficient" is a relative term, and has been ever since rifles started using elongated bullets back in black powder days. The listed BC of a typical 40-grain .224 plastic-tip is around .200, considered pitiful in 6.5mm bullets, but it out-performs lighter, blunter .224's in the .22 Hornet. Similarly, BC's have been improving in all bullets for well over a century, which is why some hunters who disparage the very concept of higher ballistic coefficient have actually been using "high BC" bullets for many years, yet fail to understand that a little more BC might work a little better.


Nosler Ballistic Tips were considered "high BC" hunting bullets before the 21st-century trend toward even higher BC's. This buck was taken at 440 yards with a 150-grain Ballistic Tip started at around 2750 fps from a 20-inch barreled .308 Winchester.