Thanks Keith for your comment. That's the way we see it too. We surpassed our 4" group size goal for five shots at 100 yards in 2005. In 2009 we determined that a new goal was necessary for the Brooke. The third test barrel with Brooke rifling shot 1.1" at 100 yards with 4 shots, with the 5th shot being a flyer, so we decided our new goal should be 1.000" for 5 at 100. We haven't done that yet, but are still load developing, so eventually we will do it.
To make it easier for very busy people to find these clips we bring them forward here on this post. We really enjoy answering your questions and will do so cheerfully if there are any more.
Tracy and Mike
The more general shots are in the first two clips and the last two get up close and personal with the details of the sine bar, follower and the rack, also the all-important, Rifling Head adjustments.
A general view of rifling operations.
Click on the image to display these clips.A little closer to the action.
A close-up of what the follower does. It follows the sine bar and drags the rack to the left or right, rotating the pinion gear and the rifling head shaft, imparting twist to the grooves.
Some dialog with this clip attempts to answer a few basic questions about rifling. No rehearsal here! Just raw footage! The dialog ends abruptly here. My fault. I cut it off a bit too short and the remainder of the dialog went on to say, "which creates a 1 in 10, 1 in 22, or 1 turn in 55" twist which is what the Brooke rifle has." Our 1/6 scale 100 Pdr. Parrott Rifle has a gain or progressive twist going from zero to 1 turn in 36"within the length of the tube.