Originally Posted by kahnjar1
#1 above is unlikely, as the barrel would be much heavier than the (added?)wooden pad.
#2 Why would a wooden pad be added to a wooden barrel to avoid contamination by sand? The folds of the skin covering (often seen on these butts) would be more likely to harbor sand than a plain wooden stock.
#3 If the gun ended up being used as a club, the existing stock would be more than sufficient to knock a person out.
Certainly the original reason for the butt "pads" remains a mystery but I do not believe that the reason is any of the above ideas. Most likely as has been said in above posts, the butt is designed to "soften" the recoil, or is just a matter of taste.
Stu, in response to your points, (I see you have no doubt handled such pieces)
Point 1. The sizes of these additions vary. Either way the centre of balance would be shifted, which may or may not have been desired by the tribal users.
Point 2. If you look at the base of the stocks with the additions, they are often quite worn. Many examples are not fur covered.
Point 3. If you say so. Hard to know at this point.
'Taste' would here be a question of cultural norms related to weapons.
Elgood mentions absorbsion of recoil but does not elaborate, but it would be interesting to hear explanations from the tribal users of these weapons, or their decendants.