Help with 7.7 mm Japanese...

I made some Arisaka cases from 30-06 cases that I have plenty of. The books say the case length is 2.070". By the time I trimmed and deburred them they measured about 2.68" which I think is ok. (a little room to grow).

But one case came out short and another a little long. I'm not worried about the long one because I can trim it a little more but I'm afraid the short one is TOO short by about 1/10". I don't know how this anomaly happened but I made some extras just in case something messed up.

So, I looked through my books, wikipedia, SAAMI specs and a few other places and I can't find the minimum and maximum case length for the Arisaka round. Can anybody help me with this?

Thanks in advance...


PS: I looked all up and down the rifle section of the SAAMI specs and didn't see the 7.7. Did I miss it or is there some reason that it's not included?


PPS: Oh, neat trick. I trimmed some case with an abrasive wheel, which cut like butter but was hard to control and see exactly what it was doing. (I'll bet that's how I got the short case) I got a mini-tubing cutter and when you put it on the neck of the pushed down 30-06 case, you can cut it off just about right. I tried to see if a regular size tubing cutter would do it but it was too wide.

My old manual states the case max at 2.269 and trim to 2.26"

Speer and Sierra carry .311 dia bullets and Hornady has .312 dia. if needed.

4895 and 4064 powders work well in this case. The 150gr is nice for general use but the heavy 180 can take medium game out to 300 yards. 700 pound animals at closer ranges.

One note.
The 30-06 case's base is under sized and in the 7.7 chamber will swell to form to the chamber. Take care with maximum charges.

This round can shoot quite well in a stock M99 in good condition
and the front sight is sweet. Well, I liked it.
Some call it the poor man's 308.............

Have fun.

An old Arisaka is not a bench rest rifle so as long as your too short case will still hold the bullet firmly enough for the cartridge to feed through the magazine then as a practical matter it will make no difference. I once converted 300 GI .30-06 cases for a Model 1891 7.65 mm Belgian Mauser. After parting company with the 7.65, even though they were technically too short, those cases were reused assembling a few other cartridges including 7.7 Japanese. That was quicker and less expensive than shortening new batches of .30-06. They shot as good as cases that were the correct length.

As you apparently know, the book difference in base diameter between .30-06 and 7.7 mm Japanese can be ignored. While expensive and hard to find Norma cases were the only 7.7 Japanese on the market they actually had the same base diameter as .30-06. Many M-1 Garand chambers swell .30-06 brass worse than the 7.7 Arisakas I reloaded for.

I also preferred using a tubing cutter on the resized .30-06 cases slightly beyond the neck impressed by the shorter FL sizing die. While the pinched in mouth had to be swelled out with a tapered punch and they had to to be resized again before going in a case trimmer it was still the quickest way. I left the sizing lube on in between the two trips into the FL sizer.

Thank you all.......

....velly, velly much.

The loads I make will be low end, there's no use to try to hot rod old historic rifles. My friend has two of them. I find them enjoyable to shoot. He has a Garand, too, but I'm going to have to pump iron because that thing seems to get heavier with every shot.

I really appreciate the info. I don't know why they don't have this listed in SAAMI. They have .303 British. Well I'll get down to making my cartridges because we have a range date Sunday week.

Update: 20 nice looking cartridges made and ready to test.

I'll take a guess that SAMMI has not bothered to piece together specifications for 7.7 mm Japanese because in the U.S. there has never been any interest in manufacturing rifles for the cartridge. It's been awhile but in addition to millions of .303s made for Britian's armed forces Remington and Winchester made .303 sporting rifles for sale in the U.S. Ruger even made #1 single shots in .303 fairly recently.

Reloads for Arisakas do not need to be any more conservative than for modern bolt action sporters like Remington 700s. Arisakas had the strongest military bolt action through the WWII period. Also they protect your eye balls better than any other Mauser based military bolt action. If you can live with the noise their safety is quicker to disengage than most Americans realize. As you swing the butt up into your shoulder you slap the safety with your palm.

Oddly I had a very attractive sporterized Arisaka -- fancy walnut Monte-Carlo stock, high polish reblue & bright bolt, Redfield receiver sight, etc. It was rebarreled to .300 Savage before .308 Win. hit the civilian market. It cost a whole $100 at a gun show. Arisakas get no respect here.

The .303 British had a lot of use in Africa with good and bad results, due to the number of Lee Enfield's sold to the settlers and the full metal cartridges.

The 7.7mm came a little later and has a very slight edge in fps over the 303, but no game animal would know the difference.

the 180gr bullet with IMR4350 is only 50fps apart......
and the 150gr SP flat base at 2650 should match the 30-06 M1 in field test out to 300 yards.

Have fun with those Rams.

The type 99 I believe has Medford type rifling and like's flat base bullets. Graff & Son normally has new brass for the 7.7 that is not priced too bad.

Here is some info I have on loading and shooting for the Japanese type 99 rifle.
Here is a quick rundown on what to look for and what works.
First there is no best load for the type 99 .They seem to be much more picky rifle to rifle than any other .
There are several reasons for this. They where made by several different makers that seemed to do it there way. Some parts do not swap rifle to rifle. Barrels act different some are chrome lined others are not. An then as the rifles became more and more last ditch the bedding was not as good .
To start with cases best to not as good .#1 Norma fit well except a little small at the head, long lasting and best for accuracy and long lasting.
#2 Remington Winchester or S&B 8x57 reformed in a 7.7x58 die also a little small at the head. The neck will be short but will grow after shooting.
#3 Graf & Sons 7.7x58 had a bad reputation several years ago {bad quality control} but has gotten much better over the last few years IMO.
#4 30-06 Reformed poor neck tension as the neck is thicker 1/2 way down since it was made from the shoulder of the case it also will be small at the base.

The type 99 is hard to get good groups because of the large hole in the rear peep sight .
Slug your bore as the larger your bore it will like less boatail bullets. A low velocity load with a fast powder or a medium velocity load with a slow powder tend to do better in large bores.
A good place to start is with a Hornady .312 dia. 150 gr. sp. bullet with 40.0 gr. of IMR 3031 with the bullet seated to the bottom of the crimp groove this will get you about 2400 fps depending on your bore size. The above will also work with 34.0 gr. of IMR 4064 or 41.5 gr. of IMR 4895 .
Chrome bores tend to shoot better with hotter loads so you can slowly up the loads by 10 % if needed.
With a tighter bore the 174 gr. Matchking can be good start with 41.0 gr. of IMR 3031 for about 2450 fps,42.5 gr. of IMR 4064 or 45.0 gr. of IMR 4895.

The Sierra 180 gr. sp can be good in some rifles with a load of 45.7 gr. of IMR 4350 for 2200 fps.

This info was copy'd from another sight if needed I can PM you the name if wanted. so use at your own risk P/S I have used the 150 gr. loads in my type 99's with good luck.

Like all other peep sights, if you work at centering the front sight in the peep you will fail or at least find it "

sureshotbob said:

[...] hard to get good groups because of the large hole in the rear peep sight . [...]

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Peep sights are more accurate than any open sight provided that you can forget you are looking through the peep. That is why you never see open sights at conventional high power matches or at old fashioned .22 LR position matches. While the Arisaka's peep was the iron sight version of Jeff Copper's Scout Scope, used correctly it retains most of the accuracy advantage of peeps.

True story. When I was a kid, about the only high powered rifle I could afford was the Jap. Ten bucks and one was mine. We didn't have a clue what caliber it was. My uncle, who had been in the war, said whatever fits the chamber has got to be it. Well, the 8mm Mauser cartridge was the only one that fit. Actually, it fit just fine. We went out to some dirt banks in SE Georgia and fired off a few. Every shot just blew the bank apart. I think the bullet was being torn up by being forced through such a small bore. Fortunately, we had a hammer in the truck. Had to use it to pound open the bolt after each shot. A year later I discovered it was really a 7.7mm and found some Norma ammo in Savannah. Point is. . .I don't think you can blow one up. I never could. Kept the gun into college when I finally sold it.

k22fan said:

Like all other peep sights, if you work at centering the front sight in the peep you will fail or at least find it "
Peep sights are more accurate than any open sight provided that you can forget you are looking through the peep. That is why you never see open sights at conventional high power matches or at old fashioned .22 LR position matches. While the Arisaka's peep was the iron sight version of Jeff Copper's Scout Scope, used correctly it retains most of the accuracy advantage of peeps.

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I totally agree with k22 fan about the peep sight. Just the one on Arisaka rifles are a little bit larger than most others.

During the post-WWII period when the 7.7 rifles were dirt cheap, there was a craze about seeing how hot you could go without blowing up the action. The answer was that it's nearly impossible to do as the Arisaka has a very strong action. My reloading experience with the 7.7 is not recent, but when I had a 7.7, I simply resized and trimmed .30-'06 brass and used .311-.313 bullets. I think I used mainly IMR 4895 powder. The bore on mine wasn't in very good condition, not quite sewer pipe but close (you could see the rifling), so I didn't expect it to group very well, and indeed it didn't. Additionally, mine must have been made fairly late in the war, as the machining was very rough. The one good thing about it was that the "Mum" stamp on the receiver ring was intact, and the stock was in pretty good shape. Basically just a fun gun and noisemaker. Another gun I am sorry I traded off. You don't see many like mine today.

After WWII, many 7.7 Arisakas were rechambered to .30-'06 in the USA. They seemed to work OK. I've fired one of those. I think that after WWII, the South Korean army was armed largely with such rechambered rifles, as they had huge stockpiles of captured or abandoned Jap rifles and needed to use them. And they did, simply by running a .30-'06 chambering reamer into the 7.7 chamber.

I've posted this before but seems like time to do it again. left to right Type 38 6.5 Jap. Nagoya 26th series matching no mum , Type 38 Nagoya 6.5 Jap. 28th series matching mum bent bolt, Type 99 7.7 Jap. Nagoya 2nd series mismatched air plane sight mum , Type 99 7.7 Jap. Tokyo Juki Kogyo 27th series {last ditch} matching no mum, Type 99 Nagoya 7.7 Jap.4th series matching mum air plane sight mono pod. Type 99 7.7 Jap. Nagoya 4th series all matching but dust cover mum air plane sight mono pod, Type 99 7.7 Jap Jinsen {special last ditch} matching no mum, Type 98 NCO sword.
pistols 1st row top to bottom Type 94 Nagoya .8 mm Nambu late war 20.5 date {may1945}all matching,Type 26 .9mm Jap. revolver rearcenaled 1931 Holster signed by U.S Gen g. Hartman, Type 14 Nambu Kokubunji.8mm Nambu dated 15.7 {july 1940}all matching, 2nd row top to bottom Type 14 Nagoya Torimatsu .8MM Nambu dated 18.11 {nov 1943} 1st series all matching but mag. Type 14 Nagoya Torimatsu 2nd series .8mm Nambu dated 19.3 {march 1944}all matching but mag & firing pin

Sounds familiar...

DWalt said:

My reloading experience with the 7.7 is not recent, but when I had a 7.7, I simply resized and trimmed .30-'06 brass and used .311-.313 bullets. I think I used mainly IMR 4895 powder.

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That sounds exactly like what I'm doing. I'm glad it's an easy conversion. 4895 is my 'do anything powder'. Even much reduced loads.

They had a pretty good Arisaka at the gun store for $239, steel butt plate and ladder rear sight. The think the markings were intact. If I had indiscriminate fiscal capability I'd pick it up, but since I don't I'm going to use my friend's guns and provide the ammo since I had a 30-06. People who ask if reloading is worth it should shoot medium or bigger rifles.

30 years ago 7.7 Arisakas with the receiver ring stamp ground off in average or better condition were $35 rifles. The one I owned readily passed from member to member at the local gun range for $35 because it included a Herter's FL die set and over 50 pieces of brass. We all managed to get 5 shot jacketed bullet groups under 1 1/2" at 100 yards off sand bags. It also grouped well with castings from Lee's approximately 185 grain .31 caliber gas check mold. We all had better rifles so none of us hung onto it.

An uncle had kept only one of the bunch of them that he brought back from the Pacific after WW II. He thought I was very ignorant paying $35 for an Arisaka. Their value could not have risen that high!

Sureshootbob;

Nice to see the 5th rifle with the wire bi-pod.
Mine had it and they are far and few between.

Nice collection !!

Sureshootbob;

Nice to see the 5th and 6th rifle with the wire bi-pod.
Mine had it and they are far and few between.

Nice collection !!

Some of the Arisakas had the so-called "anti-aircraft" rear sight, but I think that idea was dropped fairly early on. I remember seeing some website explaining how they were supposed to have been used for leading aircraft. I personally don't remember seeing any Jap rifles having that sight.

Is the ladder rear sight....

DWalt said:

Some of the Arisakas had the so-called "anti-aircraft" rear sight, but I think that idea was dropped fairly early on. I remember seeing some website explaining how they were supposed to have been used for leading aircraft. I personally don't remember seeing any Jap rifles having that sight.

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My friends Arisakas have a peep sight. The one in the store has the ladder like the old Winchesters that you slide the peep up and down according to the range. It seems that one i saw had a bigger ladder sight that was probably an anti aircraft job.

One of my three has the anti-aircraft rear sight and the wire bipod. It's the nicest one. The worst one was made in 1945. It's in like new condition, but sure is crude and ugly (as is the bayonet that goes with it). Here's my old Nambu pistol. It's the complete outfit, but I only have a photo of the gun. . .98% easy. When I was a kid they were also $10 and I got one. Ammo was "very" hard to find, and that was back in the 1960's.