Killzone, I too have a .25 MkII Bobcat and last weekend I noticed a bit of grayish dust on the stock and receiver block in that same area. I took the stock off and had the same issue. I then held a small piece of paper over the shroud hole and fired the gun (no pellet loaded) and there was a little grey dot on the paper. I called AOA about this and was told that it was normal.(?) Then to see your post a week later, it’s a bit concerning to me because, if it is in fact lead dust, are we breathing it when shooting? I don’t understand how lead, if it is lead, could get into the shroud in first place. Hopefully someone will chime in who knows more about this.