I purchased a Type 99 Arisaka some time back and only recently was able to shoot it using ammo I found offered online from a couple of different places. Most of the stuff came as PCI branded ammo, though the back stamp says PPU. Anyway, the thing I was wondering about is that about a third of the stuff I shot came out with soot along the length of one side of the spend casings, and this has me a bit worried. From what I can gather, this may just be a sign that the ammo I bought is loaded a bit too light. I already had the gun checked out by a local smith before I ever took it out to shoot it, and he gave it a thumbs up. Anyone have any thoughts on this?