Are these (3) the same or are there really some differnces between the (3)? If so, what are they no mater how slight?

Thanks.

Wouldn't stake my life on it, but believe these triplets are all identical...




Hank

They're the same but different....


As far as performance and case capacity there is very little difference.

As for interchangability, I wouldn't count on any of them interchanging. Most of these are a variation on a Paul Mauser's original 6.5x57 with different shoulder angels an such.

Good thing you didn't stake your life on it Hank!

I own a 6.5 x 57. You can neck down 7mm brass with no problems and it chambers in my Winchester.

However when I resize a case in my RCBS 6.5 x 57 die set it will not rechamber the round. There is a variation in the shoulder angle.

To get it to chamber, I have to resize it in a 257 Roberts die and then neck size it back up to 6.5 mm. Then it chambers like a new Cadillac. So I think my gunsmith ended up really making me a 6.5 x 257 instead.

I have sent my die back to RCBS with 5 cases that were shot in the rifle and they are modifying my die to fit my rifle at no charge, which is pretty generous of them I think.

It is my favorite round tho. So it requires a little extra attention. I always noticed the best women always required a little extra attention also but always was worth the effort.

Good luck if you are looking at one.

cheers and good shooting
seafire

No, they are not the same.



The 6.5-257 and the 6.5-7mm are the same. The 6.5x57 has a slightly shallower shoulder that is a bit more forward than the others. In proper chambers, the 6.5x57 should not chamber in the others, but the converse would work, but would not be advised because of excess headspace.



I have an actual 6.5x57, and it is a bit tricky to make brass for using Roberts brass - too much headspace. Necking down 7x57 brass works perfect because the wider case neck of the 7x57 leaves a small "shoulder" at the proper location to set headspacing for the fire-forming process.

I am sure it is minute but which has the greater case capacity?

Thanks.

6.5x57.

I'll post a pic of a 257, 6.5x55, 6.5x57, and 7x57 when I get home.

The primary difference, as stated earlier, is in the shoulder angle. For practical purposes I doubt you'll notice any difference. The ballistics are pretty much the same for all three. Best wishes.

Cal - Montreal

I plan to build one and "AI" it. I was thinking of using the 7mm mauser necked down to 6.5 because of the availibility of 7mm mauser brass.

So would I want a 6.5x57mm AI or 6.5-257 AI?

Thanks.

C-ROY,
As I understand it, the 257 Roberts was based off the 7mm Mauser and 6.5x57 Mauser was based off the 8mm Mauser. If you don't have a custom AI reamer and need to purchase one, make up a dummy round using the brass and bullet you desire and send it to Dave Kiff @ Pacific Tool & Gauge. Talk to him first about what you want to do. He manufactures top quality reamers at a reasonable cost.

Ol' John

Here's a pic:



From left to right:
1. 260 Bobcat (aka 6.5-250)
2. 260 Rem.
3. 6.5x55 Swedish Mauser
4. 257 Roberts
5. 6.5-257
6. 6.5x57 Mauser
7. 7x57 Mauser
8. 8x57 Mauser

It is fairly easy to see how the shoulder is a bit more forward on the 6.5x57 than either the 6.5-257 or 7x57. Note also that it's shoulder is not as far forward as the 8x57's shoulder, hence making it unlikely, IMHO, that the 6.5x57 is based on the 8x57 case. I suspect that it is it's own case design, perhaps inspired by it's two larger cousins, but not a direct descendent of either. Anyway...

BTW, if you want an improved version of the 6.5-257, I'd just go ahead and get a 6.5-284 instead. JMO...

I have a 6.5X257AI or the 260AAR.(All Around Rifle)
Mine is a Sako L579 with the magazine lengthened a bit. It has a Douglas tube, I believe a #1(light) it finished at 23ins. The gun complete with 6X Lyman scope, loaded, & sling weighs 7 5/8lbs.
You can expect :
120gr bullets--3200fps.
129gr --3000fps.
140gr.--2900fps.

My wife and I have shot a number of deer and a couple of antelope with it. Mostly with the Speer 140gr. Always exits. Pedro

PS____Has 1-9 twist.