Mystery Arisaka brass

[M-Rex]

Folks,

I reload for my 7.7 Arisaka using the tried and true .30-06 case conversions. However, when I first restored the rifle, I picked up some 7.7 rounds at a gun show. They fired fine with no problems. However, when I went to reload the cases, I found they weren't based on .30-06 brass. There are no headstamps, and the cases absolutely will not fit in any shell holder that is correct for .30-06. They do fit in my Lee shell holder #9, that is listed as being for .41 Magnum. They fit perfectly, in fact.

The .41 Magnum is the only case listed on the back of my Lee box, for shell holder #9.

Anyone have any idea what these 7.7 cases were originally?

 

[Murphster]

Here's a wild guess. Redding's shell holder for a .41 Remington Magnum pistol cartridge is the same as for a .303 Savage rifle cartridge. However, I know nothing about the Arisaka cartridge. Not sure if you could make one out of the Savage brass. Good luck.

 

[dfaugh]

Hogdon's manual

that I have notes that while many use 30-06 brass to load for7.7 Jap, the dimensions (base) of the 7.7 is actually different than 30-06 by a few thousandths...They even state that one shouldn't use 30-06 cases....

 

[jondar]

Dfaugh is correct. The case diameter of the 7.7. Jap just below the rim is larger than the .30-06 at the same spot. When the .30-06 is fireformed to the 7.7 it many times will leave a bulge in the case which could create problems later. Also, the rim diameter of the 7.7. is .478 inches while the rim diameter for the 30.06 is .473. Don't know if this is enough to keep it from seating in your 30.06 shell holder tho. I went thru trying to convert but finally bit the bullet and ordered some Norma 7.7 brass and life became much easier.

 

[Murphster]

Here's another source of info you may have already seen:

http://p084.ezboard.com/fcollectorguns35625frm3

 

[M-Rex]

Excellent info.

BTW...the actual point of difficulty is in the groove above the rim. It is thicker (read that as not as deep) than the same point on a .30-06 case. That is the only hang-up. All the other dimensions are the same.

Could these be formed from .303 Savage cases?

 

[jondar]

I don't have the case specs for the .303 Savage. I have read and been told it is "very similar" to the .30-30 Winchester case, the specs of which are: Rim diameter .506, Overall length 1.965, and Thickness of rim .065.

The 7.7 Jap has an overall length of 2.265 and a rim thickness of .037. It doesn't sound like it would work. Someone else here may have tried it.

I had ordered a set of Lee dies for the 7.7 mainly for the resizing die to set the shoulder back on the 30.06 case, but found that I couldn't make the die do this. I e-mailed Lee and the answer I received was that this die was not intended for reforming cases, only to reload cases. I sent a reply to this and heard no more from them. I should have stuck with Lyman or RCBS. Good luck.

 

[Paul "Fitz" Jones]

7.7Jap/.30-06

My first reloading business was while in High School in 1952 and on the National Guard state rifle team who gave me thousands of rounds of armor piercing ammo for practicing for the state big bore championships.
I bought 7.7 dies from RCBS including a neck sizing and cut off die that I used to pop the shoulder back on live ammo and with a Jap rifle tied to a tree I fired forming the cases then trimmed them and reloaded them for sale with .311 bullets and sold them all over the area as my first business supplying all the GI's who brought Jap rifles home from the war.
Five dollars was common for the rifles but I insisted my customers have the rifle steel tested by my night school gunsmithing instructor who also had a booklet with the Japanese rifle symbols that helped him with the rifle quality and chromium content for hardness.

 

[M-Rex]

Oh man...now that is a cool high school job. BTW, I've been using my Lee full length sizer die and I haven't had any problems re-shouldering the .30-06 brass.

 

[boo586]

jondar,

total guess here, but you may have to trim the cases close to the final length and then bump the shoulder back with the Lee Die.

This is a total guess though.

boo586

 

[20cows]

I was visiting with a gunsmith just last week and I mentioned that I had converted my 7.7 to 7.7-06 and he warned me that due to the differences in case head dimensions I was shooting a time bomb. He was really trying to discourage me from shooting the rifle again.

I've been using this thing for a lot of years. I guess I'm still cogitating on his warning.

 

[Cosmoline]

Weren't some of the 7.7mm's semi-rimmed and used for their machine guns only?

 

[M-Rex]

They were. There were a couple of versions of 7.7. Standard rimless for rifles and rimmed for machine guns.

I still have no idea what cases these were made from.

 

[jondar]

boo586, I probably should have tried that. With these Norma 7.7 cases I just use the Lee dies for reloading them. They seem to work fine for that. The cases are not cheap, but Norma is excellent brass and should give a lot of reloads. I have some in .220 Swift that I have reloaded ten to twelve times.

 

[jondar]

"I still have no idea what these cases were made from."

M-Rex, they weren't made (converted) from any other case. The 7.7 Arisaka case was an original case. As was the 6.5 Japanese case. After WW2 these rifles were brought back and there was no ammo to use in them, so .30-06 cases were used to try to duplicate them. Some rifles were converted to the .300 Savage by setting the 7.7 barrell back in the action a few threads and thereby getting rid of the "oversize" area in the chamber of the original 7.7. Some of the 6.5 mm rifles were converted to take the .257 Roberts cartridge with the mouth expanded.

 

[106rr]

There were three 7.7 cartridges made for Japanese weapons; the 7.7 rimless (Arisaka) 7.7 semi-rim (Army MG) and the 7.7 rimmed (Naval machine guns)
The rimmed version was an exact duplicate of the 303 British. In a pinch the army machine guns could feed fire and extract EITHER the rimless or the semi-rim. The semi-rims were waxed and fixed to a flat cardboard type magazine.
Many of the Arisaka type 99s were rechambered directly to the 8X57JS without reboring. The action was strong enough to take the pressure. These conversions were for Mainland China. China already had huge stockpiles of 8X57JS ammo from the Japanese puppet government of Manchukuo (AKA Manchuria) Interestingly, one of these rifles was featured in a American released Chinese movie. It was in the hands of a troubled WWII Chinese veteran