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?
Hmm..don't know if any of our resident gunners know the answer. Maybe someone who reloads? I did some quick googling and this seems to be indicative (as you found) of inadequate pressure inside the case when the round is fired. If the pressure isn't high enough, the case isn't fully pressed against the chamber wall and some unburned powder can be injected into the space. I presume the chamber looks good.
Its shit loads, but the single side bit has me worried that there may be an undetected issue with the chamber.
Nothing appears wrong with the chamber. The only thing I can think of is that maybe it's coming out along the bit that's milled out for big ol' Mauser-style the extractor claw.
I went out shooting my Type 99 recently, this time with PCI branded FMJs, and had the same issue. I'm leaning toward this being an ammo issue, though, as I also had a couple of hang fires, with one of them only managing to lodge the bullet a little ways into the barrel.
Sounds like those rounds are very weak sauce and (as was speculated above) are not generating enough pressure to form the case to the chamber wall, resulting in the powder blow-by.
I suspected this as well. Kind of makes me sad, though, as these are the only FMJs I could find in 7.7, and they were the most reasonably priced ones.
^Shooting old or odd calibers is a rich man's hobby. You could start reloading if the brass isn't total garbage.
I visited some friends for Thanksgiving yesterday, and they have an Arisaka Type 99 that's been handed down through the family (someone brought it--along with its bayonet and a samurai sword--back from Korea). The bolt wouldn't open and the safety knob was detached and couldn't be reinstalled. I took the bolt catch on the side of the receiver off, and that revealed an opening through which I was able to coax the striker out...and we found the cause of the problem: the spring inside the striker was bent on the end and had gotten lodged inside the striker. We separated the two, bent the spring back, reinstalled, and--voila!---functioning Arisaka (it had been stuck in that condition for several decades). Learned a bit about them in the process. Pretty cool. Also checked out my friend's Winchester 1890 (slide action .22 Short): And a John Constable black powder double-barrelled 12 (?) Gauge shotgun, made sometime in the 1870s (I'm guessing):
