Help on arisaka barrel threads

[me2]

Does anyone know what diameter and pitch (threads per inch) the type 38 rifles have? Is it possible they are metric? Is there reference material somewhere? Thanks in advance for any info!!

Information

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[tiriaq]

According to DeHaas (Bolt Action Rifles) the 38 has 14tpi V threads.

[me2]

Thanks for the info. Wonder how deep DeHaas goes into the Japanese bolt rifle details. I'll have to check for that book online. Seems lately I've gotten into this Arisaka "thing". Problem is most of them have chewed up bores, mostly pitted and rusty. I'm not too interested in shelling out the big bucks for a collectable grade. I just want to shoot the original 6.5X50 cartridge with accuracy. To that end I'm considering putting a new commercial barrel on a type 38 action. I have had a Douglas blank in 6.5 for a few years and now may be able to put it to good use.
Thanks again!!

[tiriaq]

DeHaas has a fair bit of information about the Arisaka rifles. Unless you are going to do the work yourself, rebarrelling a 38 might be a bit costly.
The 99 has metric threads with no easy Imperial equivalent, just shy of 17tpi.

[musketshooter]

Why in the world would you waste your $ on rebarreling it back to the original caliber? It's a pip-squeak ctg. Try and find a shootable original barrel if you must. There are numerous better 6.5 caliber rifles out there that are probably less $ than the cost of a new installed barrel.

[me2]

I have a friend with a fairly complete machine shop whom I worked for until I retired recently. Machining is not a problem.
As for the 6.5X50, I guess for me it's just an itch I need to scratch. The way things are going pricewise for components that little cartridge can get a few more "shots per pound" which like it or not all shooters will be facing soon enough. In the not too distant past when shooting those newfangled "Handrifles" was all the rage, cartridges like the 6.5 TCU slammed metal silhouetts to the ground at 200 & 300 meters with authority. The Jap round can equal them when loaded to modern (sensible) pressures and not kick the snot out of you as a bonus. Plenty of power.
I have'nt even located a T38 yet. Who knows I might luck into one with a decent bore. I certainly would not chop up a full dress Arisaka---I need a "BUBBA'D" specimen especially if I do a barrel job.
Regards,
Dick

[jmoore]

One advantage to having a new barrel is that you can run a bit tighter chamber than is commonly found on the military rifles, which tend to be a bit largish at the base. Not a thing wrong with the round, its no magnum, but it'll get the job done. If you have trouble finding a reamer to rent, it might do to use a 220 swift reamer w/ a floating pilot sized to the 6.5 bore, then cut the neck and leade in a seperate operation.

[me2]

Finding a reamer might get a little sticky!! Worse case is I will have to resort to the hard way, that being a surface grinder, sine plate, Harig dividing head and a good old length of hardened drill rod. I've made many splined core pins for powdered metal die sets that way (before EDM came along). Setting up a 30-06 or .243 would be downright boring compared to doing a 70+ year old obsolete foreign cartridge. Then again maybe I'm a glutton for punishment!!!

[riceone]

I have checked a 99 and a 38 barrel and the measurements I found are identical to what has already been said.

T38. Thread dia. 1.029" metric 25.95mm
Pitch 14 tpi metric 1.75

T99. Thread dia. 1.016" metric 25.74
Pitch between 16 and 17 tpi. metric 1.50.

I do have a T44 action with a commercial 257 Roberts barrel installed. Back years ago when I did that you could buy a commercial barrel with a long chamber and you could install and headspace without a reamer. I don't think you can find a threaded barrel of any sort now.

Also I have used the chamber cone of a T38 barrel cut it off where rear sights abutt and bored and threaded inside to 13/16th fine thread, then turned a T99 barrel down at the same location, threaded it to fit the 13/16 screwed it together with loctight and head spaced it using the long chamber methord making a T38 carbine in 7.7x58. I also have an original Test Carbine the Japanese installed a 7.7x58 barrel on back in 1939 when they were making up thier minds to go to the 7.7 cartridge. I now have reamers and headspace gauges for both the 6.5 and 7.7.

Also used the same methord to install a 410 shotgun barrel to a 99 for a friend. Worked fine. riceone

[jmoore]

The Vietnamese / Viet Cong bored out Type 38 barrel stubs and press fit( w/ cross pin) salvaged 7.62 barrels that they then cudely chambered to 7.62x39. I don't recommend the practice, though!