Reloading 7.7 Japanese

[Wolfhound]

I recently aquired an Arisaka type 99 rifle and am planning to reload for it. I have a small amount of Norma brass and have been looking into converting 30-06 brass to 7.7mm. Anyone have experience reloading this cartridge? Any favorite powders or loads?

I ordered some .312 150 grain Hornady bullets and will be using 150 grain cast bullets with gas checks.

 

[BGDave]

Check your rifling first. Some of the early Arisakas had a type of "polygonal" rifling. Other than that. brass for them shows up in the classified once in a while.

 

[Mgderf]

I'm also interested in input from this thread.
I bought a type 99 a few years back.
Almost immediately bought 150 rounds of Mr. Nambu 7.7 new loaded ammo from Gunbroker.
Shortly after, I found a set of used 7.7Jap dies at an auction.

I'm all set up to reload it, but haven't done so yet.

 

[mkgr22]

I found this report from a member of Gunboards.com:

Reloading for the T99

From his comments, it's apparent that he has done a lot of work with loading 7.7x58.

One thing that really surprised me was that he recommends forming cases from 8x57 Mauser instead of .30-06.

 

[Wolfhound]

Thanks for the information. I need to go buy some IMR3031.

I wish I had a bunch of 8x57 brass sitting around but I have been forming it from surplus 30-06 brass. Some of the ammo I got with the rifle was commercially reloaded 7.7 Japanese made from 30-06 brass. I fired 10 of them the other day and the shoulders were cracked after firing so looks like using 30-06 brass to form 7.7 is a one and done type of deal at best.

mkgr22 I tried to rep you for the link but it says I have to spread it around first.

 

[Mgderf]

mkgr22 I tried to rep you for the link but it says I have to spread it around first.

I got him for you.

 

[Wolfhound]

I got him for you.

Thank you sir!

 

[mkgr22]

Glad to help, guys.

I suppose the .30-06 brass is used because it's so much easier to get than boxer primed 8x57. And ordering it new just to convert to 7.7 would be crazy.

Wolfhound, what was the headstamp on the brass that split?

 

[Wolfhound]

Glad to help, guys.

I suppose the .30-06 brass is used because it's so much easier to get than boxer primed 8x57. And ordering it new just to convert to 7.7 would be crazy.

Wolfhound, what was the headstamp on the brass that split?

They are mostly Winchester headstamp. Box says Godfrey Reloading Supply Brighton Illinois. Most of my 30-06 brass stash is Lake City and Greek HXP headstamps. Would they be more or less likely to crack?

 

[Wolfhound]

Pictures of the cracked shoulders on the reloads.

 

[mkgr22]

They are mostly Winchester headstamp. Box says Godfrey Reloading Supply Brighton Illinois. Most of my 30-06 brass stash is Lake City and Greek HXP headstamps. Would they be more or less likely to crack?

Obviously, there's no way to tell the age of the split brass. It might have been used a few times before Godfrey got hold of it.

You might try annealing the shoulders of your brass after forming them.

 

[Wolfhound]

You might try annealing the shoulders of your brass after forming them.

I will give that a try. My 7.7 dies arrive tomorrow.

 

[bulletbaron]

Why not just go to Graf & Sons - The Reloading Authority - Your Source for Shooting Supplies - Graf & Sons and buy some NEW Prvi Partizen brass, I have loaded well over 50,000 of them and never a problem with them

 

[Wolfhound]

Why not just go to Graf & Sons - The Reloading Authority - Your Source for Shooting Supplies - Graf & Sons and buy some NEW Prvi Partizen brass, I have loaded well over 50,000 of them and never a problem with them

Thanks for the tip. That PRVI brass is way cheaper than Norma brass. Unfortunately it's not in stock at the moment. I will keep watching it for availability for sure. I simply can't afford the Norma brass. That is why I am trying to make the 30-06 conversion work. I have converted many 30-06 cases to 8x57 with no issues.

 

[Wolfhound]

I have finished a batch of conversion 30-06 to 7.7 Japanese rounds. I used H335 powder and Hornady 150 grain bullets. I annealed the 30-06 before reforming and trimming it. I experienced no case cracks during the reforming process. I am looking forward to trying them out. Here are a few pictures of the rounds. One is next to a 30-06 tracer for comparison.

 

[Broom_jm]

The biggest risk in using 30-'06 brass to form 7.7 brass is not in the neck/shoulder area of the case. The danger area is just forward of the web, due to the 7.7x58 chambers being .003" to .004" too large in diameter. This part of a high-pressure metallic cartridge is not designed to expand appreciably, with case head expansion being measured in TEN thousandths. When working with the correct brass for a given chamber, the brass should expand no more than .0003 or .0004" during the first firing sequence (fire-forming) and even less after that. Any more indicates a possible headspace problem or over-pressure situation.

By firing '06 brass in a 7.7x58 chamber, you're allowing for 30 to 40 ten-thousandths worth of expansion in the first shot. This just isn't wise and it's why gunsmiths recommend setting a 7.7 barrel back at least 3/8ths of an inch and then cutting a new '06 chamber, if that's the brass you want to use. What you're doing is only moderately dangerous, but that danger is mitigated by the extremely strong Arisaka action.

In the end, you're way better off to pony up for new brass...how many could you possibly need to enjoy shooting your 7.7 safely?

 

[Wolfhound]

Thank you for the information. I have a small amount of Norma brass and will be using that first but not enough to meet my needs. I consider reforming 30-06 as a temporary solution but it does appear to be an accepted and low risk alternative to new brass. If you can point me to someone who has 7.7 brass in stock I would be grateful.

Let's face it. There is a small amount of risk accepted when reloading and shooting or doing practically anything in our daily lives. The most dangerous thing I do now a days is drive to and from Indianapolis every day for work. When it comes to shooting and reloading my only close calls have been with over charged steel factory ammunition. Fortunately the only damage was a ruined magazine and a day of shooting cut short.

I stopped going to public shooting ranges after being muzzled by a loaded AK. I only shoot on private land now. I am sure there are plenty of folks on here who willingly accept the risk of public ranges and I am fine with that.

I will be the only one shooting these 06 reformed cases. I fully accept the risk and liability in doing so.

 

[BogWalker]

https://www.libertytreecollectors.com/productcart/pc/viewPrd.asp?idproduct=6108&idcategory=102

At $15/20 for Prvi brass they want a bit much, but it is in stock.

 

[TheBoss930]

I stopped going to public shooting ranges after being muzzled by a loaded AK. I only shoot on private land now. I am sure there are plenty of folks on here who willingly accept the risk of public ranges and I am fine with that.

Holy Cow!!! Not fun!! I would have needed a change of pants after

 

[Wolfhound]

https://www.libertytreecollectors.com/productcart/pc/viewPrd.asp?idproduct=6108&idcategory=102

At $15/20 for Prvi brass they want a bit much, but it is in stock.

Thanks for the link! Less than a dollar per cartridge is a decent price. I will get some on order and not plan on doing any more 30-06 conversions.