6.5 Arisaka from 303 Brit

[abunaitoo]

I have a Type 30 Arisaka that has really excessive head space.
So bad that if you fire it with 6.5 Arisaka shells, it's like someone sneezing in your face.
Saw a post on using 303 Brit to reform someplace.
I thought maybe I could turn a 6.5 Arisaka semi rimed, into a 6.5 Arisaka rimed case, and solve the head space problem.
Could thin the rim if bolt would not closed.
It worked great. No blow back.
I start by running the 303 Brit into a 7mm Mauser sizing die.
Next run it into the 6.5 Arisaka sizing die, with sizing rod removed, very gradually.
Push the press handle down about 1", lift, rotate the shell 1/2 turn, push down 1", keep going until sized all the way.
Trim to length.
Resize with sizing rod installed.
I turn down the rim to fit a Lee #11 shell holder. Found this would fit into the bolt face, and allow the bolt to close.
Load as normal I fire formed it to check the fit.
No problems. Shoulder didn't move. No bulge anywhere. No sign of blowback.
One problem I did find is it will not feed through the mag. The rim get caught behind the fallower.
I'll anneal the necks, neck size them, and start working on a load for this old gal.

[curator]

Try fire-forming your 6.5 Jap cases with a "o" ring around the base at the rim. That should cause the shoulder to blow forward, then only neck size the brass being careful to retain the shoulder position. Thereafter the cases will "head-space" on the shoulder instead of depending on the skimpy rim. Many use this "trick" to solve head-space problems with rimmed, bottle-neck cartridges like .303 British, .30-30, etc.

[texassako]

You could also load it with a cast bullet hard into the rifling to keep it from moving forward on fire forming. If you need a little extra case length, I believe 6.5 Carcano would work. Same base, but a little longer.

[EDG]

I don't have a Type 30
The 6.5 Jap in the Type 38 has a couple of small spots that might stop the rim but I don't consider them adequate.
The 6.5 Jap in the Type I Carcano has to headspace on the shoulder. There is nothing that the rim can stop against.

The 6.5 Jap is documented with both minimum chamber and maximum cartridges (both are referred to as maximum material condition in engineering lingo) in the European CIP standards.
Keep in mind the CIP drawings are dimensioned very differently than SAAMI drawings so the headspace dimension to a common gauge ring diameter has to be calculated.
I put together a little spreadsheet for making these calculations.
The min chamber is 1.5857
The max case is 1.5837

Both of these were calculated for use with a .375 gauge ring. Norma factory ammo checks out very close to these numbers too. You will notice the Japanese designed in .002 clearance at worst case. That is about what I would do also. It seems they were sharper than some. I have found a number of CIP designs where the maximum cartridge would be a little larger than the smallest chamber.

Anyway getting to the point if you have access to a big optical comparator you can actually measure the headspace dimension for a fired case directly. It will give you a close approximation of the chamber dimensions.
Few people have access to a comparator but the Hornady Lock and Load Headspace Gauge will also measure this dimension on a fired case. You can measure an unfired case and determine the difference between the chamber and the loaded round.

[Shooter6br]

Used 220 Swift cases. I guess they are harder to fine than "hens teeth"

[madsenshooter]

Been using your method for a long time. Might have been my post you read. Headspace is actually on that little bit of rim in the 38, my type I is elsewhere right now. It's adequate, that .060 thick little bit of rim isn't going anywhere. The cartridge was known as semi rimmed. Used to be about the only 6.5 japanese one could find was Norma, and it was woefully undersize. I wrote Norma, telling them about my use of .303 headsized case and they put up a pic on their website of ammo so dimensioned, but I've not seen any. Some of the other manufacturers brass are still a bit undersized for the Type 38's chamber, but fit the Type I pretty good, must be a bit small for the 30 too.

[abunaitoo]

That's where I saw it.
Only tried it in the type 30 so far.
The Type 38, rifle and carbine, work fine with standard 6.5 Arisaka shells.
I can't remember how the Type I shot. I'll try it after I finished with this one.
I've done the O-ring around the shell. Still got some blow back after shells were formed.
Also the neck got much shorter.



Been using your method for a long time. Might have been my post you read. Headspace is actually on that little bit of rim in the 38, my type I is elsewhere right now. It's adequate, that .060 thick little bit of rim isn't going anywhere. The cartridge was known as semi rimmed. Used to be about the only 6.5 japanese one could find was Norma, and it was woefully undersize. I wrote Norma, telling them about my use of .303 headsized case and they put up a pic on their website of ammo so dimensioned, but I've not seen any. Some of the other manufacturers brass are still a bit undersized for the Type 38's chamber, but fit the Type I pretty good, must be a bit small for the 30 too.

[bruce drake]

I used 220 Swift cases for my 6.5 Arisaka cases. Semi-rimmed cartridge like the original and its a simple neck up of the case with a trim to proper length to complete the case.

[abunaitoo]

I made 20 more cases and found I had to reduce the base diameter on a few of them.
I've been using both FC and P.M.C cases.
First batch was a mix of brands. I wanted to see what would, and wouldn't work.
Found the older PMC cases wouldn't work. Seems they are thicker higher up in the case.
Frontier cases work good, but not much around.
Had a few WCC that worked good.

[EDG]

Current Remington and Winchester cases are about .452 at the base. PPU/NNY/Prvi Partisan are .455 to .454.

It is helpful if you can put a plug gauge into the back end of your chamber and record the number. Then always use brass a little smaller. Larger brass will not chamber unless the base is reduced.

If you do not have a pin gauge you might drive a .460 cast bullet into the chamber .200 or so and then knock it back out.
Measure the ring on the bullet close to the end of the chamber.

[Japlmg]

You can form 6.5x50sr from 308 (7.62x51) brass.
308 brass being commercial brass (thinner), it is a bit easier to swage.
You have to get a case swagging die to reduce the 308 case diameter (these dies are available from C4HD).
Once you have swagged the case down, it is just run it into the 6.5x50sr full length sizing die, then trim to length.
I've made hundreds of 6.5 Japanese cases this way, to fed my Type 96 LMG.

For your excessive head space issue, by trail and error, you can form the case shoulder where it needs to be for your rifle.
Is the bolt assembly numbers matching to your rifle?
I've never heard of a Type 30 rifle with excessive head space, that had a matching bolt.

Gregg

[madsenshooter]

I did .308 before I discovered forming from .303 or Krag, which I don't use anymore because of availability. I took out an ad in American Rifleman, and was glad I didn't get many orders! I used GI brass, and it wasn't easy. It fit, the type 38s I had would accept a max head of .4575. That's a bit forward, up on the edge of the extractor groove of the .308. That didn't leave much of a rim, might have been .465, and .010 thin, but I set headspace on the shoulder. Still got a bunch of those cases floating around here. Feeding and ejection had me wondering how many Japanese got killed while trying to work the bolt of their rifle. What I made from .303 however made the rifle work like the proverbial well oiled machine. Speed didn't matter, the bolt had to be worked smartly on ejection with the .308, or it would drop them in the action. The .303 gave me the right size and thickness rim for the boltface, and with the tiny extractor groove, quite a bit of pressure from the extractor.