OF the two, the best option is the flint holder that begins with the letter L
OK enough goofing on the subject, actually both work in different applications...
Actually I've done some testing, so it was a very small sample, but in addition to "holding" the flint, does one of the two types of holders give any other advantages?
What I found was two things. FIRST..., in reproduction, military musket locks, and only in those, LEAD was better. Although the locks whether Japanese made or Italian made or Indian made, have large "throws"..., meaning the distance from the edge of the flint at full cock to the face of the frizzen is large..., they are rather slow in flint impact velocity against that frizzen. So not only did the lead when properly wrapped, hold the flint very well, but it gave some added inertia to the strike of the flint against the frizzen. This is important to folks like reenactors who are firing lots of rounds in rapid succession, without much time to tend to the edge of that flint..., and presumably was important to soldiers in combat in the age of the Brown Bess and Charleville. This would seem to explain why armies of many nations would use the material found in bullets to wrap their flints, instead of the much less expensive scrap of leather that could've been found throughout the countryside.
SECOND..., Leather was much much better for a civilian lock, Especially a good quality rifle lock, with one important point for both lead and leather... the back of the flint needs to rest against the cock screw. I found that leather was much better in my rifle locks but only performed well when either a portion was cut away to allow the back of the flint to rest against the screw in the cock jaw that held the flint in place, OR if I punched two holes in the leather holder, to allow the jaw screw to pass through the holder with the back of the flint resting against the screw. I think that the leather has a slight cushioning effect in a fast moving rifle lock, and IF the leather is between the back of the flint and the jaw screw, the impact is reduced, and I've seen a flint slightly shift when encased in leather even when the jaws were very tight upon it. Lead in a rifle lock did not work well by far... a quicker edge dulling, and gripping of the flint was a also a problem...
The two methods of rifle flint leather patterns, these get folded around the back of the flint...,
View attachment 92621
The lock with the upper leather version being used. NOTE that IF the upper version is used, and for some reason the lock jaws loosen, and the flint drop off into the grass, the leather is still held in place, and all the shooter need do is replace the missing flint.
View attachment 92623
LD