I have used both leather and lead with my larger sized locks(Kibler Colonisl, Queen Anne-L&R, etc). From a sparking performance standpoint, as well as the effect on lock reliability I can’t say that I have been able to see much, if any difference. When initially mounting a flint in lead, I have just about always had to re-tightened the jaws using lead after a few firings, sometimes twice. I have rarely, if ever had to re-tighten a flint mounted in leather. As far as weight differences between using lead vs leather, there is a difference in weight, but I’m not sure that the difference would be much of a factor on at least the larger sized locks. Lead, cut to the same size as leather has an increased weight that averages approximately 60-70 gr. The leather holder weighs about 10gr, the lead 70-80gr. My typical thickness of lead that seems to work best is .025”-.030”. I make my lead holders by hammering a 50 cal lead ball on a flat surface. The one advantage of lead I have found is that it is much easier to clean the fouling from lock/jaws, and the lead will surely outlast the leather. As to lock damage due to the additional weight of the lead, I have not noticed any, at least with the larger locks. I will say that there is a much greater possibility to do damage to the jaws, tension screw slots on the hammer, or stressing the tumbler shaft when attempting to tighten down on the lead held flint. I would suspect the latter to be the greatest possibility of damage if overdone. Having said all this, I would say that given the choice one or the other, I’d choose leather, simply because it’s easier to work with. Just some thoughts.
Shown: leather vs lead...... Note: the weight difference between the thinner(90gr) vs thicker(120gr) size 7 English flint is about 30gr.
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