Type 38

[a65l]

I'm not really much of a bolt fan but the local shop had this T38 sitting in the consignment rack. The owner dropped the price a couple of times, and I just plain got tired of looking at it. Compared to most of the Arisakas I've seen at the local gun shows, this one is downright minty.
From what I can discern by the markings, it's a Nagoya Arsenal, series 28. Right in the middle of the allotted serial range but who can say if it's right in th emiddle of production. The bore is nice and shiny clean, the mum has been gound off but the bare metal has been blued. All the serials I can find match, there is no serial on the bayonet lug, might have just been worn off, I don't see any machining marks where it was ground off. The buttstock cap is a little strange, also.
I took it to the range the other day, but was a little alarmed by the bulged case and apparently ruptured primer. So just one shot. The round went thru the paper nice and straight, so I don't think it's been rechambered. I don't know about the ruptured primer, the firing pin protrusion dosen't look excessive, but I don't know of anyone who has armorer's gauges for the Arisaka to check it.
Anyway I hope it checks out, this will probablly be th erifle that gets me back into handloading.

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[Patrick Chadwick]

don't know about the ruptured primer, the firing pin protrusion dosen't look excessive,

The protrusion is probably not excessive. Firing pins tend to wear and become shorter, not longer. This effect (which I believe was once upon a time described in detail by jmoore) is caused by the case being undersized for the chamber. When the rifle is fired, the case is rammed forwards at the same time as the primer is ignited. The fully forwards case now expands to grip the case wall as the charge burns and the gases expand. The pressure forces the primer back out of the pocket. When the bullet has left the case, the pressure eases off just a tad, so the case loses its grip on the chamber wall and is forced back, thereby spiking the primer on the firing pin, which remains quasi-static because of its mass inertia. The primer often looks as if it had been subjected to excessive pressure, but that is not the explanation in this scenario.

The answer is to first load the cases with a fire-forming charge, and/or use the O-ring trick (jmoore pat. pending, I think!) to keep the base back against the bolt face. Once the case has been stretched, then only use neck sizing from then on. And don't bother going to a gunsmith and asking him to check it with CIP/SAAMI gauges. ACWOTAM as far as I am concerned. So many Ariskas show this bulged case effect that I really doubt whether those chambers were cut to anything like the modern specifications. As a shooter of ancient BPCRs you learn to take this sort of thing in your stride, and treat each antique as if it had its own unique chambering!


Patrick

[jmoore]

The firing pin tip may merely need rounding off so there's no sharp edges. As the Arisaka's firing pin tip diameter is small, it's not as easy as it is with other rifles. Note that if hot gases cut the side of the tip, it's time for a new one! A good smith can retip the firing pin, or you can hope to get a better replacement.

The bulged case wall is, as Patrick Chadwick notes, altogether normal. Done by design, as they pretty much all seem to have generously sized chambers. Helps reliability, but not reloading.