The 375-grain
saboted slugs exit the muzzle at a blistering 1,850 fps, reducing bullet drop and all but eliminating the need to hold over at standard slug-worthy distances.
On the ammo scene there's Olin-Winchester having acquired BRI a couple of years ago, now making the saboted ammo themselves, as does Federal.
All this interest in rifled bores and saboted slug loads has further prompted the ammo makers to take another look at the taken-for-granted mediocrity of the Foster-type slug.
The choke you are inquiring about is made by Remington and is rifled for accuracy with smoothbore shotguns, but the author was not shooting a
saboted slug.
In two of my guns it averages less than three inches and is also the most accurate
saboted slug load I have tried lately.
The common availability of rifled shotgun barrels--along with the development of
saboted slugs--has improved accuracy to the point where some shotguns and loads are now delivering the same level of accuracy at 100 yards as many centerfire rifles.
With 150 grains of powder, the rifle will shoot a 150grain, .40 caliber
saboted bullet up to 2,600 fps, a significant increase over the 2,270 fps velocities attainable with a 180-grain bullet in a .50.
The combination of Knight's MK-85 in-line muzzleloader and Ramsey's
saboted handgun bullet issued in a new era of muzzleloading.
I'm also a firm believer that if Daniel Boone, Davy Crockett and others from that era had had access to our modem inline muzzleloaders using blackpowder substitutes,
saboted bullets and scopes, they would have done so.
While they don't achieve the velocities of the lighter roundballs and
saboted bullets, conicals demonstrate excellent performance on game due to their weight.
Most importantly, modern in-lines are designed to shoot conical lead bullets or
saboted pistol bullets, both of which are more accurate than roundballs, generally speaking.
Saboted muzzleloading bullets are in-line friendly and designed for hunting.