7.7 Jap converted to 30-06?

I recently came across a 7.7 jap that has been sporterized. The mum is ground off. This seems normal except for the fact that the owner claims it was converted to 30-06. I know the barrel is original. It is not marked in any way shape or form to indicate that it was indeed converted or chambered. The owner claims that it was converted by his grandfather who served in the Korean war. He also told me that if he had some 30-06 ammo he could make a group at 100 yards.
Does anyone know if this conversion is even possible? I know this sounds like a very stupid question
. I am just wondering if my friend is mistaken or maybe his grandfather just got ahold of a chamber reamer.

Hard to tell what really happened to it without a chamber cast.

The South Koreans coincidentally used some type 99s that were rechambered to 30-06. Some of these conversions, I've read, were done by US armorers.

During the Korean War, approximately 126,500 short and 6650 long Type 99 Rifles were re-chambered under American supervision at the Tokyo arsenal to fire the then-standard .30-06 Springfield cartridge. "Apparently" intended for the South Korean gendarmerie, few rifles appear to have been issued at the end of the war in 1953. These rifles were fitted with a lengthened magazine well and had a small notch cut in the top of the receiver to accommodate the .30-06 round's 1/3 inch greater length.[3] Accuracy suffered, due to the difference in cartridges, rifling rate and characteristics, but they were nonetheless functional. Conversions to both .30-06 and 7.62 NATO have also been performed by civilians, often along with sporterising modifications.

http://www.forgottenweapons.com/wp-c...a%20manual.pdf

My friend will be really happy to know this information. I knew my friend was telling the truth, but I just assumed that the gun would have had some sort of armorers markings stating that the conversion had taken place. I will look for a longer mag well and notch in the receiver.

If I find a 7.7 jap for a good price and then chamber ream and headspace, is the gun "safe" to shoot? I get a feeling that accuracy will not be the best, but will the gun be safe to fire if headspace is good? Are the receiver's rated for the CUP pressure associated with a 30-06?

Depends on how much effort was put into it. Many just had a reamer run
into the normal chamber (I have been told) so they are really a 7.7-06 and will
probably shoot safely but marginal to crummy accuracy with .308 bullets through
a .310-.312 barrel. OTOH, my Dad had a gunsmith rebarrel a K98 with a US
two groove barrel in .30-06. Superb shooter. Of course, many K98s have
been made into 8-06s, but you can't usefully shoot .30-06 ammo in them -
although I suppose it would be safe.

Slug bbl and cast chamber to see what you actually have.

Bill

The 7.7 case is a bit fatter than the 06 and the 06 case will expand to fill the chamber; only problem is it doesn't expand evenly, looks a little oval VS round. This was common, have seen maybe 6 or 7 over the years, also have seen one in 300 Savage. Neer shot one so can't comment on accuracy but would probably be a goog short range deer gun for someone who isn't into reloading the cases.

I agree with Rich/Wis and MtGun44... there arre two issues with a 7.7 Arisaka rechambered to 30-06; chamber size causing expanded '06 cases and bore size, .311-.314 for a .308 bullet. Maybe OK for cast, but it's like the '09 Argies that were rechambered to 30-06. You're pushing 30 caliber bullets down a 31 caliber bore. Not the best thing for accuracy. Minute of deer accuracy. Been there done that back in 1966.

I strongly urge you to make a chamber cast. I didn't, and got a big surprise. Mine was even odder. It turned out to be a 30-06 ICL Caribou chambering, an obscure wildcat. No markings on mine either. I eventually rebarreled mine with a used 7.7. All's well now. Here's a link to my near disaster. http://castboolits.gunloads.com/show...a!!&highlight=

Clicking 3 times no longer works to enlarge photos, sorry. Must be due to the new changes.

Quote:

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Originally Posted by birch

If I find a 7.7 jap for a good price and then chamber ream and headspace, is the gun "safe" to shoot? I get a feeling that accuracy will not be the best, but will the gun be safe to fire if headspace is good? Are the receiver's rated for the CUP pressure associated with a 30-06?

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Why not just shoot it with 7.7? Hornaday loads for it. Cabela's sells it. Its as easy to reload for as a 30-06.

don't be shooting 7.7 loads in it without trying a 30-06 to see if it chambers. You will end up with a case with almost no neck. a lot of japs were brought home at the end of the war and ammunition being scarce they rechambered the 7.7 to 30-06 and the 6.5 to 257. I havent had any problems shooting 308 bullets in the 7.7. you will get some case expansion if it is a 7.7 rechambered to 30-06, just ahead of the web. I have had good accuracy in the 7.7s I have owned. the action is reputed to be one of the strongest. Rifleman carried a story years ago, I am told about a man complained of the recoil on his 30-06 conversion and it was found that it was a 6.5 and someone had chambered it to 30-06 and he was shooting it. story seems hard to believe but I have heard it more than once. see if the gun will chamber a 30-06. If the bolt will close easily on an unfired 06, it probably is an 06. You can tie it to a tree if it chambers an 06 and fire it with a string and compare the empty with another 06 case. there were a lot of japs converted to 30-06 and yours probably is one. soldiers were allowed to bring captured weapons home and a lot of them did. I am told actual captures still had the mum, what was turned in was ground.

A lot of the 7.7's were showing up in the 06 caliber in the 50's and 60's. Many were rechambered "bring backs" and were done by the village gunsmith. All too often the chamber was oversize at the rear, some more some less but most were oversize.
Generally there was little problems with this unless you got a piece of brittle brass or old used brass or whatever and the casing split on firing then all of a sudden it wasn't much of a bargain any more. Used to be cases on record of this happening. I do not recall of anyone actually getting killed from this but there were a few eyes that were taken out, a few fingers removed, faces sprayed with molten brass etc.
It was a different world back then and if we didn't know all that much then perhaps we just didn't care but now we know what proper fitting is and also have a much better idea of pressure and what it can do.
Get a chamber cast made, see what it looks like. If it's not totally up to snuff then you have a excellent action to rebarrel.
It will accept many popular calibers with little alteration other than properly fitting the barrel. It's also one of the strongest actions ever made. The trigger is a bit of a problem but it can be cured. About the only odd ball thing is the safety but once you get used to it ,even it is livable.

If you have one that has had an '06 reamer run up the chamber take a short piece of Scotch tape and wrap the base of the cartridges before you fire them the first time. This will center the case and allow the expansion to be even. After that neck size if you are using '06 dies or you will resize the expanded cases.

Like happens when war production requires lots of production, the bores vary a lot on the 7.7X58

I know someone that uses .308" coated bullets and 0.310" cast boolits in his!

Same bullets and boolits he uses in the aught six.

the jap 7.7 is one tough action. it will handle anything you can get it to feed. i read walker's book where they were trying to blow actions. the jap was still going strong after 17 enfields and 03a3's were in pices along with 98 mausers.

my father had a 09 argeintine that was rechambered to 06. it would not shoot. till i loaded with 7.65 bullets. .313 dia.

Quote:

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Originally Posted by madsenshooter

The South Koreans coincidentally used some type 99s that were rechambered to 30-06. Some of these conversions, I've read, were done by US armorers.

During the Korean War, approximately 126,500 short and 6650 long Type 99 Rifles were re-chambered under American supervision at the Tokyo arsenal to fire the then-standard .30-06 Springfield cartridge. "Apparently" intended for the South Korean gendarmerie, few rifles appear to have been issued at the end of the war in 1953. These rifles were fitted with a lengthened magazine well and had a small notch cut in the top of the receiver to accommodate the .30-06 round's 1/3 inch greater length.[3] Accuracy suffered, due to the difference in cartridges, rifling rate and characteristics, but they were nonetheless functional. Conversions to both .30-06 and 7.62 NATO have also been performed by civilians, often along with sporterising modifications.

http://www.forgottenweapons.com/wp-c...a%20manual.pdf

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IIRC, the Turks did something similar with the notch cut in receiver for some 7.65x54 M38/M1903 Mauser rifle actions which were too short to handle the 8mm Mauser cartridge.

Just for you young felows an outfit called Hunters Den back in the 50's took every surplus rifle they could get and ran a 30-06 reamer in them and sold them in the backs of magazines. You could get 30-06 russian rifles, jap rifles argentine rifles including 1891's ect. All guarenteed to shooot at least ONCE. These converted guns sold for like $18.00 each.

Julian Hatcher wrote of an incident where two boys fired .35 Remington cartridges in a 7.7 Jap rifle. It blew up on the third round sending steel shards into the shooter's brain, he survived after delicate brain surgery.

From what I've read on the incident of a 6.5 being chambered for .30-06, the guide for a .30-06 reamer could not fit the throat of a 6.5 bore unless ground down. If so the roughly ground reamer guide rod would wallow out the throat into a cone. Under those circumstances the rifle would act as a squeeze bore, swaging the .30 bullet down to 6.5 before full chamber pressure was reached.

The Chinese converted many captured Jap rifles to 7.92X57. A rifle brought back from Korea should have the bore slugged.
7.7 Jap ammo may not be easy to find, but I'd much rather leave one in the original chambering unless already bubba'ed beyond redemption.

I remember reading about that 6.5 Jap rifle rechambered to 30/06 in the American Rifleman , I think, in the early 60's. The gunsmith that had it sent it to the NRA and they test fired it. The picture of the recovered bullet was a hoot. It looked like a pencil.
The gunsmith said the owner explained that he couldn't get the reamer into the chamber until he ground down the pilot. You would think he might have wondered about that but he went ahead and did it anyway.

Past summer, gent showed up at our shooting club with a decently sporterized type 99 Arisaka he'd found in a local pawnshop for $100. He was going to shoot it for the first time. I happened to walk past his bench when he was prepping to shoot and noticed his Arisaka. Own a couple type 38 Arisakas that'd been rechambered to 257 Roberts, so they are 6.5x257R (6.5x57) and can easily spot one. Gent had a box of Remington 150 gr 30-06 next to the Arisaka. Rifle had been rechambered to 30-06 (stamped on barrel), so it still had the original 7.7 Jap military barrel. Told him not to expect any good accuracy with the rifle, .308 bullet going down a worn .312 or so bore and etc. Rifle had an inexpensive 3-9 scope on it, so guy set his target at 25 or so yards to check its zero. I returned to my bench to shoot. Gent will eventually be shooting the Arisaka at a 100 yd target. When Arisaka owner finished shooting and had retrived his target, he searched me out to show it to me. LOL, darn Arisaka was shooting 3 shot cloverleafs at 100 yds. A nickle could cover most of his groups.

I now of one that uses .308 bullets in the original chambering. I theink Type 99s are like SMLES . . .

Bore varies greatly.