Friday, June 12, 2015

Making 7.7 Japanese ammo from .30-06 cases

This article should be of interest to certain historical rifle shooters. It covers how to make ammunition for the World War Two Japanese rifles chambered for the 7.7x58mm round. This would be the Type 99 Arisaka rifles that are still somewhat common out there, both sporterized for hunting and stock collectibles. Here's mine. I've had it about thirty years but it's basically been a wall-hanger/safe queen for lack of ammunition since the US military pretty much put the Japanese ammo plants out of business in 1945. Today, the gunwriters tend to call the cartridge that it fires "7.7 Arisaka" or just 7.7x58mm. Back when I was growing up we always just called it "7.7 Jap" and the rifles were always "Jap rifles" regardless of the actual make or caliber. Now this may offend some of the more PC individuals out there, or possibly the Japanese, but you know what? We won that war so we'll call it whatever we like.

Anyway, if you have one, you'll know that ammo's tough to come by and expensive as hell. Only a couple of companies make it commercially now and it's spendy stuff. If you're just going hunting and only need 20, you might not mind dropping $30-$40 for a box of 20 rounds. But for target shooting or plinking? That's pricey range fodder.

So here's an alternative that many people use, me included.

Start out with a .30-06 case, commonly available pretty much anywhere.

I put mine in this low-tech but effective fixture made of nails pounded into my workbench. It holds the case with the neck over the edge of the bench, as shown.

Next, we call over Mr. Dremel and knock about half of the neck off above the bottleneck. Gauge used: Mk I eyeball.
This is what you want:
Measurement's not a big deal at that stage because you're just taking off excess metal before trimming to size using the case trimmer.
2.27 inches will do you just fine per the Lyman and other reloading guides.
Now after beveling and chamfering the case mouth, you lube that case and run it through the 7.7 resizing die. This sets the original neck back about .130 inches and expands the case mouth from .308 to .311.
Prime your case and charge it with whatever powder you fancy. This batch is getting Win 748 just because I've got a pound lying around. Then seat your bullet. Here again, you can use cheap 7.62x54mm (Russian) pull-down pullets because they, like the 7.7 Jap, and the .303 Enfields, are .311 diameter. Or if you want to tighten it up a bit, Hornady makes a killer .312 round nose soft-point. My Enfields love those.
Keep your overall length under 3.15 inches and any rifle your loading for should chamber them easily.
Finished product below: One round of 7.7 Japanese.
Here's twenty newly-minted rounds. Took me about an hour, but I enjoy time at my loading bench so it's all good. These particular rounds will actually go to another blogger that some of you follow. She also has a Type 99 Arisaka that she inherited. These are loaded light because I suspect that hers hasn't been fired since shortly before Douglas MacArthur sailed into Tokyo Bay.
And by way of comparison, one of the new rounds (left) next to the .30-06 that the case started out as. Not really much of a difference, eh? Just shorten the case, move the neck back, and expand the case mouth. Simple really. And it beats hell out of paying for store-bought.


  1. What are the ballistics on that round?

    I remember reading it wasn't very effective compared to the 30-06.

    1. I wouldn't sell it short. Published specs for the military round were 175 grain bullet moving at 2,440 fps. Mine are 174gr. soft-point rounds and they're probably right around that speed, although I haven't chrony'd them yet.

    2. Little slower than a 30-06, but yeah, sounds decent.

      Maybe what I'm remembering was how things got at the end of the war. I know the quality of the rifles got pretty bad, and I imagine the ammo got worse, too.

  2. You numba one with a bullet, GI !

    Be sure to let us know how it went at the range.

  3. Reminds me that I recently found a small batch of re-sized brass for .243 Win. that I'm going to use as a basis for some soft-shooting (think Trail Boss) rounds to introduce my daughter to centerfire rifles.

    I'd had a quantity of sized and primed cases in a plastic bin for 30 or more years, and had always assumed my dad had prepped them for me, from .308, when I was a kid.

    First thing I did was sample test a couple of the primers (they've been in climate-controlled storage). They're fine. But I found that I had to set the shoulder back a wee bit, which challenged my assumption that they'd been for me, as the rifle I'm loading for is a Remington 600, similar to the one I had as a kid.

    Then I ruminated on the fact that the headstamps are TW-43. Well, these ain't no .308 cases, then, are they? And I remembered that Dad had had a .243 in college, before becoming a Jack O'Connor acolyte in the early '60s. So it's possible these cases were sized and primed when I was still in diapers or even before I was born.

    Anyway, I trimmed and chamfered the case mouths on my Case Trimmer 2 (which looks just about identical to yours), and as soon as I acquire some Hornady 75 gr. pills, we should have some lovely ammo...only 72 years in the making!

  4. :-) Seems to be a waste to let a perfectly good old gun just sit in the closet. Especially since the US gummit gave Dad a free trip to the Pacific in hopes of interfering with those carrying those Arisakas.

  5. Do you ever anneal the cases with a torch before doing this?

    1. I do not. Haven't seen the need and they hold their shape and re-size nicely after firing.

  6. More incentive to start reloading... I have a ton of Lake City 30.06 brass my dad saved over the years, and (besides M1, 1917, and 03A3, ) an Arisaka that I have never fired due to lack of ammo... Another thing on my list of things to do.. Thanks for the info...

  7. Nicely done sir! And I'm sure she'll like them!

  8. The Japanese might have taken offence at the quality of the "war souvenir" Arisaka a friend of mine had years ago. Probably late war manufacture. It was such a POS that they would be embarrassed to claim it. It is the reason I wound up with a .300 Winchester Magnum (long story printed elsewhere) so I cannot say I hated it.