Finding that just right combination of a specific powder...charge...sabot...bullet... and the primer used for ignition that shoots the absolute best from one of today's hot modern in-line ignition rifles can take a great deal of experimenting. This is especially true for the shooter who is looking to achieve top end velocity with great accuracy and tremendous big game knockdown power.
Generally speaking, most of today's rifles are fully capable of getting just about any properly sized sabot and bullet combination to shoot well enough at a hundred yards to take big game. However, to really tweak the accuracy and punch that most of these rifles are capable of delivering these days, you just may have to play around with sabot and bullet combinations that do not come pre-packaged.
The nice 3/4-inch center-to-center group pictured below was shot while doing some early testing with a pre-production run of Blackhorn 209. It was shot with a .50 caliber Knight DISC Extreme (Long Range Hunter model), shooting 110-grains of the new powder - and a saboted 250-grain polymer tipped .451" diameter Barnes all-copper "Spit-Fire TMZ" bullet.
Loading with the special sabot Barnes had developed for the boat-tail base of their TMZ bullet, the rifle and powder charge would easily keep this sleek polymer-tipped spire point bullet in nice 1 1/4- to 1 1/2-inch clusters at a hundred yards. But, fortunately, I was also testing a new sabot for Harvester Muzzleloading. And that design combined the styling of the Barnes sabot with Harvester's patented new "Crush Rib" design - with nearly microscopic ribs running lengthwise along each of the four sabot sleeves, or petals as some like to call them. By just switching to the new sabot design, my groups immediately tightened. I also found that the narrow ridges or ribs of this sabot allowed me to push the sabot-bullet combo down the bore with a lot less effort.
More recently, I have been doing a great deal of my test shooting with a .50 caliber T/C Triumph that I quickly discovered had an extremely tight bore, making it just as extremely tough to push a standard sabot and bullet combination down to seat on the powder charge - especially with the ramrod that comes with the rifle. Using a heavier duty "range rod", I could wrestle pre-packaged sabot-bullet combinations, like the Hornady "SST" or the Barnes "Spit-Fire TMZ" down the bore, but it still took more effort than it should - making it difficult to be sure that the round was seated exactly the same from shot to shot. So, I began to load with the Harvester "Crush Rib" sabots (one for the flat-based bullets, one for the boat-tail based bullets). Loading got a whole lot easier, and accuracy improved significantly.
One of the very best shooting loads for this rifle has been 110-grains of Blackhorn 209 behind the Harvester Muzzleloading saboted 300-grain .451" diameter "Scorpion PT Gold" bullet (ignited with a CCI 209M primer). The load is good for 1,966 f.p.s. and 2,571 f.p.e. at the muzzle. And out at 200 yards this load still generates more than 1,300 foot-pounds of knockdown power. Several of the 200-yard groups shot with the rifle and load have been right at 2 1/2 inches across center-to-center.
Another of my favored test rifles is the MDM QuicShooter. This .50 caliber break-open model has a looser .502" bore, and the "Crush Rib" saboted 300-grain "Scorpion PT Gold", with the black sabot it is packaged with, nearly falls down the bore. While the rifle, shooting the same load as the Triumph, is still good for minute-of-whitetail accuracy (2 to 2 1/2 inch groups) at 100 yards, it turns into an entirely different beast when the same bullet is loaded with Harvester's tighter fitting red .50x.45 sabot. This sabot has slightly thicker sleeves and a slightly larger diameter base. The company designed it for the Savage Model 10ML II .50 caliber rifle, and the smokeless powder loads it shoots. Those charges burn more efficiently when compacted by a tighter fitting sabot-bullet combination - and so do charges of Blackhorn 209.
Loaded with the red "Crush Rib Sabot", the fit of the .451 "Scorpion PT Gold" bullet in the MDM rifle's .502" bore is about as ideal as it gets. The combination is snug enough to offer some resistance on the ramrod, which means it will continue to compress a charge of Blackhorn 209 when the bullet and sabot are solidly seated. Still, the fit is forgiving enough to allow the combo to be pushed down the bore without having to fight the ramrod. As for accuracy, with the 110-grain charge of Blackhorn 209, the rifle, sabot and bullet will regularly print 1- to 1 1/4-inch hundred yard groups.
The "Scorpion PT Gold" bullets you find in your local gun shops come with the standard black .50x.45 "Crush Rib Sabot". However, if ordering by phone or through the internet, they can be purchased with the tighter fitting red .50x.45 sabot. Just go to Harvester Muzzleloading's website at www.harvesterbullets.com .
Before the announcement of Knight Rifles shutting down operations, I was wringing out the prototype of a new rifle they had hoped to introduce - the "Extreme Ultimate Slam". And as you might gather from the model designation, this was to be a real magnum powerhouse - built to shoot loads of up to 150-grains of Blackhorn 209. Even so, I found the prototype to be more at home with charges of 130- to 140-grains. And with some non-pre-packaged sabot and bullet combinations, it was a tack-driving powerhouse.
One bullet that has proven exceptional out of this rifle's turn-in-28 inches twist Green Mountain barrel has been Hornady's .458" diameter 325-grain "FTX" bullet - a slightly rounded polymer-tipped semi-spitzer designed for loading into .45-70 lever-action cartridge rifles. This past spring I put quite a few of these through the Knight prototype, loading with either the orange .50x.458" sabot offered by Muzzleload Magnum Products...or the standard .50x.45 black "Crush Rib Sabot". While the MMP sabot loaded easier with the bullet, the "Crush Rib Sabot" proved most accurate. And with hot 130- and 140-grain charges of Blackhorn 209, the rifle and loads as often as not shoot inside of an inch at a hundred yards. And thanks to the ribbed sleeves of the sabot, the .458" bullet loads as easily as most .451" bullet do with a non-ribbed sabot.
At the muzzle, the 130-grain charge gets the bullet on its way at 2,017 f.p.s. - with 2,938 f.p.e. Out at 200 yards, the 325-grain Hornady bullet drives home with more than 1,400 foot-pounds of knockdown power. The bullet is shown below with both the orange MMP and black Harvester Muzzleloading sabots. The expanded bullet was shot into expansion medium at 100 yards...and retained close to 90-percent of its original weight.
Another great choice for the hunter looking for a super hard hitting, deep penetrating bullet for hunting elk and other really big game could be the Barnes all-copper .475" diameter bullets that company produced for the Knight .52 caliber rifles. And these can be loaded into a .50 caliber rifle like the "Extreme Ultimate Slam" prototype using the light blue .50x.475 sabot offered by Harvester Muzzleloading.
Several years ago, I played around with the .475" diameter Knight/Barnes all-copper 275-grain hollow-point (just a different diameter of an Expander MZ style bullet), loading it with the Harvester .50x.475 sabot and got it to shoot superbly with 110-grains of FFFg Triple Seven out of a .50 T/C Omega. At a hundred yards, the big hollow-point commonly shoots inside of 1 1/2 inches - and it is a great close cover or deep woods bullet that floors whitetails on the spot. However, when I tried shooting the heavier and much longer (1.210" long) 375-grain Barnes/Knight spitzer style hollow-point with the same amount of FFFg Triple Seven - accuracy went out the door. The best groups were usually still 3-inches or more across.
The turn in 28-inches twist of the .50 caliber rifle is apparently not fast enough to impart enough spin on the bullet to properly stabilize it in flight. However, when I upped the charge to 120-grains of FFFg Triple Seven, accuracy did improve - with a few groups right at 2 inches. The added velocity seems to add stability to the long all-copper bullet. I knew that FFFg Triple Seven creates some pretty high peak barrel pressures, and didn't take the charge to 130 grains.
Blackhorn 209 has a more progressive burning rate, allowing the powder to give higher velocities with a lower peak pressure. So, I recently pulled out some of the .50x.475 sabots and a few of the big 375-grain Barnes/Knight .475" spitzer hollow-points - and with 120- and 130-grain charges I've been enjoying some very acceptable accuracy.
The loads are being shot out of two different .50 caliber rifles - a T/C Triumph and the Knight prototype. With 120-grains, both rifles tightened some groups to just over 1 1/2 inches. And with 130-grains of Blackhorn 209, both rifles are now grouping regularly at 1 1/2 inches at a hundred yards. That powder charge gets the bullet out of the 27-inch Knight/Green Mountain barrel at 1,911 f.p.s. - with 3,037 f.p.e. At 100 yards, the big bullet hits with 2,400 foot-pounds of retained energy, with 1,950 f.p.e. at 200 yards, and with 1,600 f.p.e. at 300 yards.
Not everything that's great comes pre-packaged. When it comes to muzzleloader sabot and bullet combos - experimenting is half the fun of in-line muzzleloading, and often the only way to find an optimum load for a particular rifle.