Reply with quote #1
I'm looking to build a rifle in something other than 6.5 Swedish or 260 Rem, just because I want something different. I do a lot of reading, mostly internet articles and blurbs, and I like the 6.5-257 Roberts or 6.5x57 Mauser options. But now I need to make a final cut. So, I'm looking for input as to which cartridge might be the better choice.
This rifle is being built on a mauser action so for now it will just be used for hunting and some general target shooting. If I like the way it shoots, I will probably build on a better platform for some low key competition shooting. So, here are my questions.
Are there any major differences in the two cartridges? Is it better or easier to neck up or down? Is there any fire forming which must be done with either cartridge? Is there any appreciable performance gain in an improved version (28, 30 or 40 degree)? Do the improved versions burn out barrels any faster than non-improved? And finally, are there any published pressure specifications on either?
I appreciate any comments. I know some of these questions may seem obvious, but I've seen conflicting info on some of these, so just looking to get input from some seasoned shooters.
Reply with quote #2
I saw that no one has shown any interest yet, so I'll pipe up.
I juat answered another thread with about this same thing.
I have a rifle (and dies) that were built by P.O. Ackly back in the late 60's. It is a 6.5X257 Roberts AI and as I said in that other thread, thats a pretty convoluted title because I form my brass from 7X57 with a straight neckdown to 6.5 then fireform.
It is a very peppy rifle. I shoot the 125 SKG most of the time, at about 3100 fps with 4831. If I ever have the time I'm going to try to work up some loads using slower powder as there is sone room left in the cases with 4831. I haven't shot it in a while, but I just finished loading 50 rds for it, that will last me a long time. This rifle has never shifted zero on me and I haven't moved the scope since I got it 10 yrs or so ago.
It isn't a bad overbore, and I don't shoot it much, so I don't think I'll ever shoot the barrel out. It is a fine caliber though. The rifle has taken a big black bear, an elk, several Antelope and enough deer to fill a truck or two.
Woops...I forgot to adddress your other concerns!
6.5X257 Roberts and 6.5X7X57 are the same as far as I can tell.
Yes you will get a little more performance out of the AI version depending on bbl length, maybe 100 to 200 fps. As neither would be a huge overbore, barrel life should be quite good. You will have to fireform to the AI version but you can do that as you practice, sight in and hunt. Not a big pain in the a$$ either way.
Reply with quote #3
I think you may have received some misinformation. Both the 257 Bob and 6mm Rem are simply necked down 7 x 57 Mausers. If you neck down--the parent-- the 7 x 57, to 6.5mm/.264 you could call it
6.5 x 6mm Rem
264 x 6mm Rem
6.5 x 257
264 x 257
6.5 x 57
264 x 57
and they ALL are the same cartridge.
Hope this helps.
Reply with quote #4
I've own a 6mmRem, 6mmAI' and a .257Bob and all shot well with the right loads. I can't think of a single reason why a 6.5x57 or better yet 6.5x57AI wouldn't make a great flat shooting deer rifle but you'd need a minimum 24" barrel length to get the AI version up close to full potential. Now with a 26" Shilen in their magnum sporter contour .650 at the muzzle it should make a sweet deer stand / bean field rifle. Please do let us know how it turns out when you build yours.
Reply with quote #5
Here is some load info for the improved version...
If you like being able to get cheap ammo, grafs listed
6.5 mauser by PRVI for 16.99 a box.
Are you building on a commercial action or military?
Reply with quote #6
I had to dig out my Hornady manual to look this all over, but here is the scoop.
1) the 6.5x57 is European cartridge based off the 7x57, but with a slightly different shoulder angle (18 degrees, 55 minutes).
2) the .257 Roberts retains the same shoulder angle (20 degrees, 45 minutes) as it's parent cartridge, the 7x57.
Therefore, the 6.5-257 Roberts and the 6.5x57 are NOT the same. Th 6.5-257 and the 6.5-7x57 (note the difference from the 6.5x57) would be the same.
3) While the 6mm remington is based off the 7x57, it has a much different shoulder angle (26degrees) and so it, too, would be different.
In essence, you can call the 6.5- 257 Roberts and a straight neck down of the 7x57 as the same cartridge, but NOT as most of the combinations mentioned. Assuming they are the same will lead to mistakes and frustrations, with the possibility of injury to the shooter - though probably remote.
Reply with quote #7
6.5x57 either ai or straight. run your 7x57 brass thru a 6.5x57 fl die and your done. sounds like a good build. 6.5x55 swed. is also a popular choice for people building on a small ring mauser. many shoot the original barrel. if your building on a large ring mauser you may also consider a 6.5x284.