Handloading For 7.7 x 58 mm Jap

[Lambo]

In need of Data!
Also, I've been reading that 30-06 Cases can be converted to 7.7 Jap.
Can this be true ?,
"the brass for this caliber is easily made from .30 ’06 brass. Chop off about a 1/4 inch, then run into the sizing die and trim to length."
Sounds to easy!

 

[R.W.Dale]

NO NO NO NO NO! 7.7 jap uses a larger case head than 06 so the lifespan for converted brass would be rather brief. don't believe cartridge drawings you find for this round. Actual chambers can vary WILDLY from the SPEC


http://www.grafs.com/metallic/780

Just buy the stuff!

 

[pcoliver]

I use cut down, 30-06 military (Lake City) brass. It is cheap, and it works just fine.

I recently made some cases out of 8x57mm brass, and there is no cutting involved. I have not tried them yet.

 

[fatelk]

I've used reformed 30-06 brass for years. Light loads are fine, but when I load full pressure loads I do get a bulge.
Take a micrometer and measure 30-06 brass, then measure some Norma or WWII surplus Japanese ammo. The difference is only a couple thousands IIRC, but it's a noticeable bulge with full pressure loads.

It sure is nice that good brass is available now. Back in the day Norma was the only game in town.

 

[Sunray]

Go here for data.
http://www.accuratepowder.com/data/...(7.82mm)/7_7 58 Japanese Arisaka page 288.pdf
I have data in my Lyman book for a 150, 180 and 215 grain jacketed bullet. Plus 155 cast, 205 cast and 214 cast all with gas checks. Send me an e-mail and I'll send it to you. It does say that bore diameters can vary between .311" and .317", so slug your bore too. [email protected]
Midway lists Norma brass and ammo. Not exactly cheap though. $20.49 per 20. $91.99 per 100. Loaded Norma ammo runs $37.99 per 20.

 

[moosenut245]

Using 06 to load 7.7 x 58 Jap

R. W. Dale, Seems you have tried to do this without success and I would like to know more about what if any brass can be used to replace this round? I was reading in a reloading book I have, ABC's of reloading 9th editon that has information that this will work if you "FIRE FORM" the shells after sizing? Could this work?
Thanks
Moosenut245 (Wayne)

 

[8mmman]

Re-formed 06 to 7.7 Jap

I used reformed 30-06 brass for years. Light loads are fine, but when I load full pressure loads I got a bulge and all when well for years till I had a side blow out of a re-formed 06.

Split my stock and blew the floor plate out. Now I use Graf brass and it works great.

YOur right it sure is nice that good brass is available now. Back in the day Norma was the only game in town.

Just buy some good brass

 

[rcmodel]

The difference between 7.7x58 Arisaka and 30-06 is so slight to be meaningless.

There is more difference between 30-06 brass manufactures then there is between the two calibers.

7.7x58 = .472" rim - .470" base.

30-06 = .474" rim - .473" base.

People have been using reformed 30-06 brass with perfectly fine results since WWII ended.
Because for the first 20 years or so after WWII, that was the only option there was if you wanted to shoot them.

rc

 

[Sport45]

I have a bag of the PRVI brass from Graf's but I haven't opened it yet. The reformed SL55 cases I've been using have been working fine.

The best shooting bullets I've found for my T-99 have been the 174gr .312" offerings fom Hornady. I start with a "start" load and work my way up until the elevation is right at 100 yards with the sight flipped down and stick with that. I've used IMR-4320 and AA-2495 and the load wound up being about mid-range in both cases.

 

[The old man]

I see people talk about forming brass from '06 or 303 and there was a lot of thought in developing one of the strongest actions ever built. If you think about it, acquired American or British ammo could be fired in the Arisaka but not the other way around.
I bought one for $15 in 1963. There was some rust and the stock was pretty rough. My fathers friend had sporterized one so I had some good info. The bore was bright! I was told that the earlier guns had chrome lined barrels. I sporterized it, took my first deer with one shot and it still shoots GREAT!

 

[Curator]

Jap 7.7 chambers can vary a lot between rifles and manufacturers. So too can commercial brass. The best way is to make a chamber cast and operate from a position of knowledge. I have measured 7.7Jap chambers as large as .482 head diameter. Old (1950s) Norma brass measured .476. US Lake City .30-06 measures .472. I have found that a single wrap of 3/8" wide plastic electrical tape around the case head in front of the extractor groove will center the case in an oversize chamber for fireforming brass made from .30-06 or 8mm Mauser. This evens out the "bulge" instead of having it all on one side. Cases so formed hold up much better. I also stick with published data and don't try to make a magnum out of it.