Long Throats No Impediment
Q: I note that a number of your rifles have long-throats (free- bore) which means the bullets have a greater distance to jump before they engrave the rifling. I've been told that a bullet which has to jump a great distance before being jammed into the leade and lands is not as likely to shoot accurately, since it is probably going to be slightly out of alignment with the bore. Yet all of your long-throated rifles are accurate and show a worthwhile gain in velocity. Why do you think this is so?
A: As you are probably aware, chamber throats and leades vary tremendously. Some have no cylindrical section at all and some have longer leades with shallower angles. They all serve to guide a bullet into the rifling as on-centre as possible. The most latitude occurs in the neck wall section of the chamber. Besides the tolerances in chamber dimensions, case neck wall thickness varies, but the variation is the same here, regardless of bullet seating depth. The only problem (real or imagined) which arises from a long-throated rifle is that it eliminates the variable possible by altering bullet seating depth. In a standard length throat bullet seating depth is important for changing the distance the bullet relates to the lands. In most long-throated rifles, there is no way to seat bullets out far enough to just miss touching the lands, and light bullets are too short to allow the bullet to come anywhere near the lands and still leave enough bullet shank inside the case neck for ample support. Magazine length or even action length may also be factors if they limit overall cartridge length. Speaking from my own experience, I have owned and still own several long-throated rifles and they are all very accurate. But a long throat cut by an incompetent gunsmith may guide a bullet into the rifling off-centre and not produce good accuracy. In that event, there will be no way to correct it through adjustment of bullet seating depth.