Is there any difference between brass cases for the 257 Roberts and the new +P loads? Can I use old brass for the new +P loadings? If there is a difference, how do the manufacturers mark the cases?

I doubt there is any difference. That would require a different manufacturing process. I am sure they use the same process for the drawing steps of all the X X57 brass.

MC: Based on the lots that I have, it depends on whose brass you are dealing with. The regular W-W SUPER brass, and the earlier SUPER SPEED, is 10 to 15 grains lighter that the newer brass with +P in the headstamp. FC and FRONTIER +P marked brass is about the same weight as the similarly marked W-W brass. So is R-P brass, though it is not marked as +P. I have not yet loaded any of my older Winchester brass, so can say nothing about its perfomance. I have found that I can use the heavier +P brass and the R-P brass with the same loads.

Cheers, Al

Mort,

I have two 257 Roberts rifles and use Winchester +P brass for them. My load is 45 grains of H-4350 with 100 grain Nosler Partitions. It shoots very well in my rifles
As always, work up to the load that is safe in your rifle starting at about 42 grains.

Don

quote:

Originally posted by Mort Canard:
Can I use old brass for the new +P loadings?

I sure do.....I use WW cases and load them to max pressures.

I have Winchester brass that is not marked Plus P and some that is marked Plus P. I load either with a Plus P loading.
Like, when is Winchester brass not Winchester brass? (Substitute Remington, Federal whatever brand floats your boat.) If Winchester is tied up running big batches of say 30-06 or .270s or one of the short magnums, they might contract with Remington or Federal to make up that batch of say .243 Win. or maybe 7x57 Mauser. Just because the headstamp says Winchester doesn't mean Winchester made that brass.
Even if Winchester made the brass, there could be a significant difference in weight as not all the cases in a particular box were all made from the same dies.
Paul B.

Thanks Folks! I will start with one of the starter loads from the powder mfg. and work up.

I neck up the Winchester 257 Roberts brass for my 6.5 x 57 Mauser... and they work just great.. being loaded up to some high pressures at times...

I noticed using Rem 257 Brass, that I get neck splits a lot more frequent than on the winchester brass...

On the subject of brass.
I've always used Remington brass, since my Step Dad always used Rem brass. But, my oldest son shoots High Power Rifle competition, the Camp Perry stuff. He uses Winchester because he says it's much better than Remington. So, when I bought the pair of 257 Roberts rifles, I decided to try the Win +P brass. I gotta say I like it. It seems harder than the Rem brass, and better formed. The only issue I had with it was one flash hole was off center, so I used that case for a dummy round with a bullet installed. I use dummy rounds for setting up the Wilson seaters.
I like the Win brass and will buy more of it.
By the way, Natchez has Win brass at a good price; that's where I bought the 257 brass.

Don