256 Newton caliber options

okdee · Post by **okdee** » Thu Jun 30, 2011 5:59 pm

I am looking for options to shoot my grandfathers customized Ariskia type 38. Looks like he rechambered it from 6.5mm to 256 caliber. I assume 'Newton' as it was done in the late 1940's or early 1950's.
I appreciate any good direction.
OKD

airedaleman · Post by **airedaleman** » Thu Jun 30, 2011 6:28 pm

It may be a 6.5mm X .257 Roberts conversion. This was the most popular "fix" back then. (I had one rechambered back in the mid-50's. Quick and easy - and effective.)

awp101 · Post by **awp101** » Thu Jun 30, 2011 7:22 pm

airedaleman wrote:It may be a 6.5mm X .257 Roberts conversion. This was the most popular "fix" back then. (I had one rechambered back in the mid-50's. Quick and easy - and effective.)

Or 6.5-06 like the one I tried to haggle on recently.

Get a chamber cast done to be absolutely sure of the chambering.

airedaleman · Post by **airedaleman** » Thu Jun 30, 2011 9:22 pm

awp101 wrote:
airedaleman wrote:It may be a 6.5mm X .257 Roberts conversion. This was the most popular "fix" back then. (I had one rechambered back in the mid-50's. Quick and easy - and effective.)
Or 6.5-06 like the one I tried to haggle on recently.

Get a chamber cast done to be absolutely sure of the chambering.

Chamber cast is the way to be certain. A quick - very primitive - check would be to get a hold of a .257 cartridge and drop it into the chamber. If it disappears (so to speak), the chamber's obviously longer than that of a 6.5X.257.

I think we'll all be interested in what you find out...

airedaleman · Post by **airedaleman** » Thu Jun 30, 2011 10:03 pm

Something else to consider...

The 6.5mm Arisaka case has an OAL of 50.5mm, The Roberts case 57mm, and the '06 case 63mm - just about half an inch longer than the Arisaka. '06-length cartridges would require magazine modification...

earlmck · Post by **earlmck** » Thu Jun 30, 2011 10:16 pm

airedaleman wrote:It may be a 6.5mm X .257 Roberts conversion. This was the most popular "fix" back then. (I had one rechambered back in the mid-50's. Quick and easy - and effective.)

Yep, odds are 99 to 1 this is what you've got there. I have one sitting in the garage just like that. Unfortunately it doesn't shoot real well, but it can spray those 6.5mm bullets out there at real good velocity!

Note that the gunsmith probably used a 257 Roberts chambering reamer, but the gun is still 6.5mm (if you are lucky -- mine slugs out to be .268 to .269 which is probably a good part of my accuracy problems). So essentially you have a 6.5X57. Probably. The idea to drop in a 257 Roberts case (or 6mm Remington) and see how it chambers is a good one. The 6mm Remington may be easier to borrow a sample of than .257 Roberts, when you go shopping for a case to see how it chambers. I made my 6.5X57 cases from some old 6mm Remingtons I had left over from a rifle I'd given away (necking up to .257 and then to .264 in two steps and then annealing).

Have some fun with her.

okdee · Post by **okdee** » Thu Jun 30, 2011 10:22 pm

Thank-you greatly. Interesting enough, the Norma 6.5 MM round does not completely go into the chamber. I have been in contact with my Gunsmith and will do a chamber casting. Are you able to measure the length of brass for each caliber? The shoulder of the Norma 6.5mm seem to be stopping full entry into the chamber.
Boy, howdy. Shore do appreciate this.
OKDEE

awp101 · Post by **awp101** » Thu Jun 30, 2011 10:32 pm

okdee wrote:Thank-you greatly. Interesting enough, the Norma 6.5 MM round does not completely go into the chamber

Norma 6.5 what is the question. 6.5 Japanese? (6.5x50SR IIRC)

okdee · Post by **okdee** » Sun Jul 24, 2011 7:13 pm

Well, I got a egg/mud combo on my face!

The gunsmith was still out of town, who I was going to get a chamber casting done on this "Supposed rechambered rifle" and I kept on thinkin about what round does fit in this chamber?

WEll, I started rehashin old ammo boxes and reloads from my Dad and me, and came across some 6.5mm Jap rounds - and some of them had been fired! This is crazy, I thought to myself.... Dad shootin 6.5 mm Japs out of a rechambered rifle??? Or maybe I was wrong and it was not rechambered....Would not be the first time I thought wrong, - ask the wife!

Anyways, I compared the box of 6.5mm's that I had tried to load into this Arisaka type 38 customized rifle. And the box I found the reloads in and a few that had been fired....

BINGO - I had grabbed a box of 6.5mm Carcano. Not 6.5 Jap. They are different cartridges and the 6.5 Carcano will not load into a 6.5mm Jap rifle!! I grabbed one round from the box of 6.5 Jap and loaded right in that rifle, almost like it was made for it!!!

I did further research in the Cartridges of the World box and found the following:

Cartridge -------- Bullet Dia.---Case Length---Crtg. Length---Neck Dia.---Shoulder Dia.---Base Dia.---Rim Dia.
-----------------------------------------------------------------------------------------------------------
6.5mm Arisaka-------2.63-------2.00------------2.98---------.293---------.424-----------.455--------.471
6.5 Carcano-----------2.65-------2.05 ------------3.02---------.295---------.430-----------.445-------.448

So, I have learned something new and it should definitley stick with me!

Cheers,
OKD

256 Newton caliber options

256 Newton caliber options

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