Home Forums Hunting & Shooting Custom Rifles & Wildcats 6.5x257 question

Disclaimer: I have zero experience with the .257 Roberts... never so much as seen one beyond online photos. I do own a 6.5 Carcano. I also recently aquired a 6.5 Jap, though I do not have any ammo or brass.

My question... I frequently see that 6.5 Japs were converted to 6.5x257. Can anyone tell me about such conversions with the Carcano. Is there THAT much difference between the two? I recently saw a gun that is clearly a Carcano, but is stamped 257 on top. I could be talked into it but I want to know what I'm getting into. How tricky is acquiring or creating brass for 6.5x257 Carcano. I can find nothing online about 6.5x257 Carcano.

Thanks in advance...

The Carcano is just wrong for that conversion. Rim diameter and bbl groove diameter, Hornady used to make .266 dia bullets, but finding any now? Hmm. Rim dia, you are looking at .023" difference IIRC. Save your money.

It is nothing more than a 6.5-.257. since 6.5 x50 brass was not easy to find, it was common to rechamber using a 257 Bob reamer. then throated accordingly. Easy to find brass, just neck up 257 Bob brass. I had one for a while but it was chambered incorrectly and the chamber was too long. I sold it and built a 6.5x55 instead.

Yeah, I'd just shoot the Carcano as is.

PS...I see you are from Dillingham...I almost died in Dillingham (of fright) when a Wein 737 blew a bunch of tires. After they got us off the plane (quick) some wonderful soul grabbed the booze cart and treated us to all the 'relaxing beverages' we wanted. Maintenance was schidt...but customer service was top notch.

You know there is a factory 6.5x57mm round out there. No need to coble up a wildcat that is virtually the same.

https://en.wikipedia.org/wiki/6.5%C3%9757mm_Mauser

Graf and sons in stock

https://www.grafs.com/retail/catalog/product/productId/73809

Clarification: this is in reference to an existing 6.5x257 Carcano that has already been so converted. I do reload for all my stuff, but all my stuff is pretty standard. I have no familiarity with conversions or wildcats. I was wondering about, if I acquire this rifle, the ease or difficulty of converting brass and the best route to go.

@flintlocke ... Rural AK can provide some wild times, and not always from a direction you see coming.

The rifle that got me started reloading was a 6.5x257 on a Jap rifle rechambered by a gunsmith in Milford, PA. The mum was even intact. His name escapes me at the moment. This was a common conversion shortly after WW2 with bringbacks from the Pacific war until Norma ammo & components, including 6.5 Jap, became available in the US. The 6.5x257 is the ballistic equivalent of the European 6.5x57, & simply requires expanding 257 Roberts brass up to .264". A tapered expander is likely the best way, although I have fired 257 ammo in the chamber to get there with no ill effect. The 4350s are possibly the most useful powders with 140s & 160s using 6.5x57 data available in many older loading manuals. I never tried any lighter weight bullets.

In the 50s or 60s PO Ackley tested many different actions to destruction by overload. He came to the conclusion the 6.5 Jap was one of the strongest actions made. Not so with the Carcano. Loads should be kept to a significantly lower pressure in the Italian piece. Carcanos also may have a .268" groove diameter somewhat limiting your bullet choices for best accuracy... something they aren't particularly known for in the 1st place. Unless you are doing the conversion yourself, with an already owned reamer, & have no real expectation of much beyond the ballistics of the original round while using slightly more powder, it seems to be a rather worthless venture. If buying an already converted rifle a trip to a reputable gunsmith would be (more) $$ spent to inspect an otherwise questionable purchase. Reloading dies aren't likely available at your local gun shop either. If it were me I would just keep walking.

257 Robts brass is much like hen's teeth these days. 7x57 Mauser could be necked down but is also less than common nowadays. Norma brass for the original Jap or Carcano brass turns up from time to time but isn't cheap. As much as I hate so say it, a Ruger American Predator in 6.5 Creedmoor will vastly outperform the Carcano conversion at a reasonable price.

Sorry, I misunderstood, it's a done deal then. Ok, the rim problem has been addressed by the builder...you should be able to proceed with loading with 6.5-.257 data keeping in mind the Arisaka was reputed to be one of the strongest actions made. Thank you, PO Ackley. I just sold mine, but I started with data from Speer #9, 6.5 x.257, no problems. Then I went to Hornady #3 and used 6.5 x 57 mm Mauser data, which a lot of people do. No problems there either. Frank de Haas thought the Carcano got a bad rap, and he described as a well made military action with no known dangerous faults. I am kind of wondering how the gunsmith that did yours worked around the Mannlicher style en bloc clip?
Now, the 6.5 x 57 Mauser shoulder is at 1.752" inches...the 6.5 x .257 is at 1.727" Erich...Jesus man that's a difference of .025"...not my idea of "virtually the same".

I haven't actually seen the rifle firsthand yet. I can tell you it looks sharp cosmetically (clear, sharp photos), which is what caught my eye. I have wondered about the en bloc clip too - it's still there, or at least the housing for the clip is still there. The seller appears to know very little and has been no help with regards to specifics.

So it is if you say so, would work out perfect, clean up the old chamber, off the shelf dies, correctly head stamped brass, printed loading data and factory ammo.

I have been told that 6.5-257R and 6.5x57mm are not the same cartridge

What he said . . .

a gunsmith could quickly change that easily....

also not many people ever seem to think of it, but if 6mm Remington Brass is available and 257 Roberts isn't.... that can be necked up also.
which I think might be easier than necking down 7 x 57.

I have a 6.5 x 57 Mauser, and necking down 7 x 57 is sticky and needs to be trimmed a little before being useable..
necking up 6 mm Remington, is not issues... at least on mine...

and I also have an Arisaka that was reamed out to 6.5 x 257... and the ammo that came with it... is necked up 6mm Remington.