Have you ever wondered why the relatively small-caliber so-called "Kentucky" and "Pennsylvania" rifles of the 1700's were built with barrels that were commonly more than 40-inches in length?
It all kind of boils down to the availability of black powder and lead in those days. In the wilds of what later became "New England", gun powder and lead for casting into round balls were both in very short supply. Yet, wilderness settlers had to keep meat on the table, and to protect a family from ever present dangers, such as bears, wolves...and earlier native settlers. Common bore sizes of that time were .40 to .45 caliber, and a typical powder charge of FFg or FFFg black powder was 50 to 70 grains.
The longer barrels better tapped every bit of velocity and energy these rifles could produce. So, what kind of muzzle velocity did these old rifles produce...and was a 40+ inch barrel really necessary?
Back in the 1960's, Dixie Gun Works took a .40 caliber percussion test rifle (mostly just a barrel, lock and trigger), and conducted a series of chronograph tests...beginning with a 40 inch barrel - and slowly shortening it down to 20 inches. Shooting 47-grains of FFFg (DuPont) black powder behind a cloth patched 93-grain .395" round ball, the 40-inch barrel gave them 1,770 f.p.s. (646 f.p.e.). With the barrel at 30 inches in length, velocity was down to 1,642 f.p.s. (556 f.p.e.), and with the barrel shortened to 20 inches velocity was down to 1,509 f.p.s. (470 f.p.e.).
Even with today's hotter burning black powder substitutes, barrel length still plays a critical role in the ballistics produced. When shooting a 100-grain charge of some earlier blackpowder substitutes out of the 22- to 24-inch barreled .50 caliber in-line big game rifles of the early 1990's, muzzleloading hunters did good to get a saboted 240- or 250-grain .44 or .45 handgun bullet out of the muzzle in the neighborhood of 1,650 f.p.s. Muzzle energy levels produced by those loads were generally in the 1,450 to 1,500 f.p.e. range, and 100 to 125 yards was considered the maximum effective range.
Blackhorn 209 is currently the black powder substitute, or as the label proclaims "High Performance Muzzleloading Propellant", that tends to produce the fastest velocities - when loaded in the same volume amount as any other modern black powder substitute. To fully tap the performance of this and other black powder substitutes, today's modern in-line No. 209 primer ignition rifle makers are once again beginning to stretch barrel lengths.
One of the rifles I first loaded and shot with Blackhorn 209 was a .50 caliber Knight DISC Extreme - with a 26-inch barrel. Relying on a 100-grain volume measured charge, I was able to get a saboted 260-grain Scorpion PT Gold (Harvester Muzzleloading) bullet out of the muzzle at 1,947 f.p.s. (2,189 f.p.e.). Out of an inch longer Knight .50 Long Range Hunter model, velocity moved up to just 1,971 f.p.s. (2,238 f.p.e.). However, loading this same load in the 30-inch barreled Traditions .50 VORTEK Ultra Light LDR, the added three inches of bore allowed a more complete burn of the powder charge - and velocity jumped to 2,018 f.p.s. (2,350 f.p.e.).
My favorite hunting load for the 30-inch barreled VORTEK Ultra Light LDR is a 110-grain volume measured charge of Blackhorn 209 and the 300-grain version of the Scorpion PT Gold bullet. I like both the added weight for greater knockdown and higher b.c. of the bullet for better retained down range velocity and energy. The load gets out of the longer barrel at 2,009 f.p.s. (2,686 f.p.e.). It is a super accurate combination for this rifle, and has been deadly on longer range whitetails.
The shortest .50 caliber No. 209 primer ignition muzzleloading rifle I've shot with Blackhorn 209 has been the LHR Sporting Arms break-open Redemption Carbine. This rifle has been designed for going into heavy brush, to make game move, and hopefully offer a shot. It's my opinion that the 20-inch barrel of the carbine is simply not long enough to fully utilize a 110-grain charge of Blackhorn 209 - but just to check, I chronographed the load at 1,823 f.p.s. (2,211 f.p.e.). That's a far cry from the velocity, with the same load, out of the 10-inch longer VORTEK Ultra Light LDR barrel.
I normally load, shoot and hunt with the 24-inch barreled Redemption Rifle with a 110-grain charge of Blackhorn 209 behind the 300-grain Scorpion PT Gold. The four-inch longer rifle barrel gives a more complete burn of the powder than the 20-inch carbine barrel. Velocity is 1,946 f.p.s. (2,520 f.p.e.). When hunting with the Redemption Carbine, my load is 100-grains of Blackhorn 209 and the 300-grain Scorpion PT Gold. Keep in mind, this carbine length rifle was not intended for 200+ yard shots. At the muzzle of the short barrel, velocity is 1,795 f.p.s. (2,144 f.p.e.). A buck that would give me a shot at 50 yards in heavy cover would be hammered to the ground by close to 1,900 foot-pounds of knockdown.