Anybody do chamber castings?

[MoBoost]

6.5x57 or 6.5-257 Roberts - a common conversion.
http://forums.gunboards.com/showthread.php?235904-Arisaka-Type-38-Carbine
[Broken External Image]

 

[Shriner]

6.5 jap ........... Swede
base .476 ......... .480
body .451 ........ .480
shouder %37....... 50.58%
neck .291 ........ .299
lt 2.008 ........ 2.165
base to shoulder1.532....... 1.712
total lt 2.992 ...... 3.150
base to neck 1.709 ...... 1.856

 

[Travis73]

Maybe I labeled my measurement wrong. What I called the "base" was taken just above the recess where the extractor claw bites. I didn't mean for it to indicate rim dia. The largest number I get from the cast, as close to the bolt face as possible, is .473 dia.

 

[Travis73]

The cast shows a light line where the cartridge (brass) ends. On the casting, from the "bolt face" to that line is 2.11". The cast doesn't show the bolt face of course. Just the chamber area where it locks up. So this number isn't exact.

 

[Shriner]

Did you use wax ?

The casting metal works better , it will shink at first but go to full dia in a short time . Your number don't match any common 6.5 mm's , a 6.5 swede should not load in a 6.5 jap ,if your meausrements are right someone may of wildcated that gun .

 

[Travis73]

Yes, I made a wax casting. I agree, the measurements don't point to exactly what cartridge this should be. Im looking at the low melting metals mentioned above. Im thinking a new cast and measuring is called for.

 

[MoBoost]

Yes, I made a wax casting. I agree, the measurements don't point to exactly what cartridge this should be. Im looking at the low melting metals mentioned above. Im thinking a new cast and measuring is called for.

Low melting metals and new casting ain't gonna tell you anything different than what I told you in post #11.

Other than match chambers, there are some variations of reamers and deapth of cutting; especially conversions! You will have to fireform brass to this rifle if you want to use it in current configuration. So, just get to it. If 6.5x55 chambers with pressure, load it with "cream of wheat" fireforming load - and you have your brass.

I still think that you got necked down 7x57 conversion - 6.5x57 or 6.5-257

 

[gaseous maximus]

Low melting metals and new casting ain't gonna tell you anything different than what I told you in post #11.

Other than match chambers, there are some variations of reamers and deapth of cutting; especially conversions! You will have to fireform brass to this rifle if you want to use it in current configuration. So, just get to it. If 6.5x55 chambers with pressure, load it with "cream of wheat" fireforming load - and you have your brass.

I still think that you got necked down 7x57 conversion - 6.5x57 or 6.5-257

I think so too. Years ago, a bunch of 6.5 japs were rechambered to fire 257 roberts cartridges. I picked up a jap rifle, in arkansas in the mid 90s that had been reworked, complete with a hand made walnut stock. It was real close to a screw up for me. I had previously rechambered several to 6.5x55 and that was the plan for this one. with out thinking i stuck it in my lathe and started to ream. something didn't seem right and it wasn't. I had already been cut to 57. I was able to set the barrel back a thread, and it was ok.

 

[Travis73]

6.5 Swede. By fire forming several brass and taking measurements that's what i have found.

Thanks everyone for the good advice.