chamber conversion 6.5 Arisaka to 6.5 Swede
 

In looking at the SAMMI dimensions for the 6.5 X 55 Swede, they list the inside neck dimension as .263 minus -.0028 or plus +.0008, so in essence a max inside neck diameter of .2638 ... and I always thought it was .264, but I guess that's close enough, or is it?

I was using the cartridge/chamber conversion tool on AmmoGuide, and I was surprised to find they did not include the 6.5 X 55 Swede as a do-able conversion for the 6.5 Arisaka.

I have an old Arisaka with a burnt barrel, but acquired a newer 6.5 Arisaka barrel in good shape, cut to 17.75 " with a target crown on it. Always considered doing the ream to Swede as I already own 600 empty brass, dies, and lots of powder and ball for the Swede round.
Now, I'm wondering if the AmmoGuide folks are just a little too exact, or if they are correct in telling me that I should not consider this conversion.

I still think it would work, but might have to turn the inside necks of the 6.5 Swede brass just a smidge ... maybe not. Any cartridge aficionados out there that could set me straight? Do I really need to worry about .0002?

I just realized that maybe I should have posted this in "Gunsmithing".

Mods please move if necessary.

Well RR, I'm guessing your pressure item IS why the AmmoGuide folks said "no no" to the possible conversion. But I'm having a devil of a time finding listed chamber pressures for the Arisaka 6.5, though I know Ackley did some torture testing of it years ago and found it to be about the strongest of all military actions.

That being said, the only pressure listing I can find show the numbers in some oddball measurements. CPI is the measurement, standing for Commision Proof International ... some European style SAAMI type organization. Anyway, they list the Arisaka 6.5 with 43 CIP (X 1000) and the Swede 6.5 round with 55 CIP (X 1000).

Another old Speer load book from 1954 merely states that the Arisaka 6.5 round loaded with the 138 grain bullet used in WW2 developed about 2400 fps and about 35,000 pounds. Thats all it said.

So, it would appear that your concern about the pressure being an issue might be the concern also being voiced by the AmmoGuide folks.

Still, I find it had to believe that the Arisaka action, long konwn for it's superior strength, would be too weak to handle the Swede round.

Maybe this will just have me saving my money and leaving this project to stay leaning in the cabinet, like it has for the past 25 years.

Probably not. But if you want to see why I question it, try to look up P. O. Ackley's testson military actions. The arisaka was the only one he could not get to fail. I think he eventually sent a barrel downrange after loading too-large-for-bore bullets in the chamber and the action remained undamaged thought eh barrel eventually parted ways with the action. action was considered to be the strongest of all military bolt actions at the time of the testing .. and that included the M98, the Springfield, Enfield ... all of them.

My gun is actually a type 44, a short carbine model of the type 38 6.5 round. The Arisaka military round was a semi-rimmed cartridge. There was a 5.6 X 50R round that some follks used to open up to 6.5 X 50R.

Anyhow, most important thing you've illuminted for me is that Hogdgon states that a .264 will do. Again I'm not surprised as the Arisakas had a reputation of having generous bore dimensions.

I guess my step 1 is to slug my newer Arisaka 6.5 barrel to determine it's land-groove dimensions and then go on from there.