CW- Looks like your linking modern expeirnce to old tech., does not always work. The 1853,1861 and 1862 Ord. Manuals state(1862) on page 271,that, "Made of merino or serge. The material should be composed entirely of wool, free from any mixture of thread or cotton and of suffciently close texture to prevent the powder from sifting through:that which is twilled is perfered. Flannel is used when other materials cannot be conveniently obtained." No mention of silk in my 1916 artillery manual either.
Perhaps it changed when silk was easier to get or was it because they no longer had to worry about spark ignition because the shoved the projectile in first from the rear; in modern breech-loading artillery. Who knows?
Silk was around prior to the civil war. If it was the best thing to use, they would not have used Wool in their MUZZLE loading artillery . Perhaps silk is less resistent to spark. (if #3 fail at his job and allows air in the vent.)The men who wrote these books often spent their entire carrers in the study of muzzle loading artillery, they knew what they were doing.
Why second guess them.? Just play it safe.
RCHJr.