7.7 Jap., which brand of 30-06 brass?

[curiousgeorge]

I know that you can make 7.7 brass from .30-06 because I have done it.

I also know that it is not 100% safe, UNLESS you are shooting fairly mild loads because I had 2 cases to rupture, maybe split or crack would be a better description, right above the head on the first firing and several others looked really bad. Was it a bad gun or bad chamber? I don't know, and at the time I didn't care. I quit while I was ahead and bought some Norma 7.7 brass. No more problems. The gun that I had was not safe with the .30-06 cases. Just for info purposes, the cases that failed were all once fired Winchester.

The above being said, if I were planning on shooting nothing but light cast loads, I would use military brass. Maybe I am wrong, and if so I appologize in advance, but they seem to be the toughest stuff around.

Steve

[Multigunner]

A 7.7 Jap with a chamber cut at minimum or nearly so, and not noticably worn, may have no problem with reformed .30-06 brass, but another 7.7 Jap rifle otherwise I dentical but having a slightly looser cut or worn chamber might have problems.

The potential for case blow outs was recognized long ago, when these rifles were occasionally rechambered for the .30-06 cartridge.
Use of a full house .30-06 sporting load, or a M1 Ball cartridge with its slightly higher pressure, in one of the looser chambered of the rechambered rifles might result in more stress on the brass than a well below maximum load in '06 brass reformed to 7.7 and fired in a 7.7 chamber.

They used to recommend that only mil spec '06 cases be used for reforming to 7.7, due to tougher brass and thicker case walls.

An old trick to avoid un necessarily lopsided expansion of a case a tad small for the chamber is to wrap a turn or more of a narrown strip of cigarette paper or some other thin material around the base above the extractor groove for first firing of the reformed case.
Besides insuring even expansion to reduce stress, centering the case for first firing then neck sizing only insures a near dead center firing pin strike, and presents the bullet to origin of rifling without cant that can affect accuracy.

I always mark the rim of my .303 cases and rotate 180 degrees on second firing. I found these well centered cases reduce group size by half compared to first firing.
Another trick is to size only 2/3rd of the meck. The still evenly expanded portion of the neck centers the neck in the chamber neck, further insuring presentation to OR without cant.

While many older sources state that a well centered pin strike has little or no effect on accuracy, these sources usually are repeating results of experiments done when sensitive large dia mercury compound berdan primers were the norm.
The smaller dia, less volatile compund, and much smaller anvil, of modern day large rifle primers seem to benefit more from a well centered firing pin strike.
Probably not always true with all combinations of primer, action, etc, but ever rifle and pistol I've worked on to insure a well centered strike showed noticable improvement in group sizes immediately.

[Guesser]

I had a five gallon bucket full of once fired FA 58 NM that I have been using, no crimp and after annealing it is easy to form, trim, and fire form. It seems to last a long time. I don't keep track of how many times it is loaded.

[303Guy]

Looking at Steve's pages it seems that the 7.7 Jap is almost identical to the 8x57 Mauser. Surely those would be easier to reform to 7.7?

[Multigunner]

Looking at Steve's pages it seems that the 7.7 Jap is almost identical to the 8x57 Mauser. Surely those would be easier to reform to 7.7?

A member of another board who has collected and restored many Japanese rifles once posted that he had deliberately fired a 7.92X57 cartridge in a 7.7 Jap chamber just to see what would happen. So apparently its possible to get a 7.92 in the chamber and close the bolt (though probably requiring some effort to close the bolt). Could be that this is only the case when a chamber is badly worn or headspace far out of specs. IIRC The rifle he tested, in a proper remote test firing booth in his gunsmithing shop BTW, was a non restorable piece sacrificed for the experiment.
I forget the exact results but I believe the action was ruined.

With typical oversized mil spec chamber necks and bores such catastrophic results might not have been the case if the older 8X57J cartridge were used.

Due to the legendary strength of the Arisaka action many a wanna be P O Ackely has hammered the bolt shut on unsuitable cartridges just to brag about their Arisaka not blowing up.
Hatcher's Notebook mentioned a incident where a teenager managed to fire two .35 Remington rounds in a 7.7 without apparent damage, the third shot shattered the action and sent fragments deep into the young man's head. He survived surgery.

[bruce drake]

what 303Guy was suggesting and I do this out of preference for loading for my 7.7 Arisaka is to use 8mm BRASS and then reform the case to 7.7 specs. What you are left with after the reforming is a 7.7 Arisaka Case with a neck 1mm shorter than the official specs (8mm is 7.92x57mm while 7.7 Arisaka is 7.65x58mm).

The first time you neck the case down from 8mm, you'll have a false shoulder from where you are moving down from .323 to .312. With cast boolit loads, the first firing will fire-form the shoulder to match the chamber and its good to go for further shooting.

Bruce

[303Guy]

Yes, I was meaning the brass for reforming to 7.7 Jap. Although I have heard rumors of the strength of the Arisaka action. Forgive my lack of clarity.

A 8x57 round forced into a 7.7 Jap chamber would likely push the bullet back into that case. That plus the oversize bullet would surely be catastrophic!

[Multigunner]

Yes, I was meaning the brass for reforming to 7.7 Jap. Although I have heard rumors of the strength of the Arisaka action. Forgive my lack of clarity.

A 8x57 round forced into a 7.7 Jap chamber would likely push the bullet back into that case. That plus the oversize bullet would surely be catastrophic!

It was my own lack of clarity.
I'd meant that since the fellow I mentioned had managed to chamber a 792X57 in his 7.7 then the cartridge cases should be very close in configuration so the 7.92X57 case should work well if reformed to 7.7 specs.

If there is any remaining slack near the base one could use milspec 7.92 cases which were usually extra tough for use in the LMG. A thick side wall near the base should prevent blow outs.

A reformed case without a recognizable headstamp other than number codes would be easier to mark in some way as being for the 7.7 rifle. To avoid confusion at a later date.
Electric pencil should do the trick.

[Me not you]

I've used 8mm Mauser for 7.7 Arisaka loads with no problems at all. What I normally do for the first firing (in a bolt rifle only) is load the Hornady 100gr 0.312 pistol bullet over about 12 gr Unique. I also lube the cases. On firing, the lube helps the case slide back against the bolt face. The case is then nicely fireformed to the chamber with no stretching. This load is also pretty accurate, good for rabid raccoons in the yard etc. After that I neck size with a LEE collet die.

[psj12]

I make, and have made, brass for the 7.7 from 30-06. I find I need to ream the neck to remove the thicker brass where the sholder is pushed back. After fireforming I only neck size to reduce wear on the cartridge base. I think 8mm would work better. I just have lots of 30-06 and the tools to do it.

[0verkill]

I always mark the rim of my .303 cases and rotate 180 degrees on second firing. I found these well centered cases reduce group size by half compared to first firing.
Another trick is to size only 2/3rd of the meck. The still evenly expanded portion of the neck centers the neck in the chamber neck, further insuring presentation to OR without cant.

I'll have to try that with my 303.

As to the 7.7 I think it all depends on your situation. 8x57 will be easier to reform, but 30-06 is probably more abundant to most of us. How tight your chamber is may limit your ability to use reformed cases. A lot of these were wartime production rifles so a chamber cast may be in order to see if '06 brass or others can be reformed.

[BeemerMark]

Hornady now sells loaded rounds for a reasonable price. I bought a few boxes and then reload it. Cheaper than then the 20 rounds of Norma brass. Used to do the 30-06 route but not only is it was too much work but I did not like loaded rounds of 7.7 labeled 30-06.

[0verkill]

Is the hornady 7.7 PRVI ? (PPU headstamp)