Help on arisaka barrel threads

[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.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[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