Is there a difference in the +P brass? Is it necessary for decent hunting loads?

As I understand it, the +P Roberts brass has a little thicker walls. It is recomended that you use a little less powder beacust the capacity is less. I use + p Winchester brass in my Roberts, and using the data from the barnes 100 grain X Bullet with 100 grain tripple shock. I get great results...tj3006

While I've never cut one apart I doubt there is any difference between a +P case and a new manufacture 257R case. The older 257Roberts ammo was loaded to lower pressure(close to 50000 I think!) because many guns were built on the older style surplus actions. The +p was loaded to higher pressure (60000+ same as the 6mm)for use in the new manufacture rifles.

The new 257 and +P cases I have yield the same capacity. I load both to around 60,000.

I've never checked to see if there is a real necessity for +P brass but I do use the same Win brass as TJ with very good results.

quote:

Originally posted by ramrod340:
While I've never cut one apart I doubt there is any difference between a +P case and a new manufacture 257R case. The older 257Roberts ammo was loaded to lower pressure(close to 50000 I think!) because many guns were built on the older style surplus actions. The +p was loaded to higher pressure (60000+ same as the 6mm)for use in the new manufacture rifles.

The new 257 and +P cases I have yield the same capacity. I load both to around 60,000.

As I understand it, there are several cartridges in the world that have traditionally been underloaded due to the existence of weaker rifles so chambered, (ie., .30/'06, 7X57mm) but the .257 Roberts is NOT one of them. There has never been a weak factory-made .257 Roberts, and I am not aware that SAAMI has ever reduced the pressure specs for any round in order to accomodate some gunsmith who may have been guilty of chambering a weak action for any particular cartridge.

In other words, there is no real reason why a factory would underload the .257 Roberts, but they did, for no known reason!! Additionally, there is absolutely no need for any "special +P case" for this round, any more than there would be a need for a +P case in 6mm Rem., 7X57mm, or 8X57mm. The 57mm Mauser case family is as strong as any on the market.

As Elle indicates, the "underloading" of .257 Roberts ammunition remains an unsolved mystery. Perhaps it was done since it shares the same case with two cartridges (7x57 and 8x57) that ARE kept at lower pressures due to being chambered in some weaker guns. And maybe that's the reason that the .244/6mm Remington used a very slightly modified shoulder angle with the same basic case, so that it would be standardized at a higher pressure? Make no particular sense, but then it was thought up by humanoids.

The "+P" mark on the brass is merely to distinguish the load as it comes from the factory from "non +P" ammunition. The brass is identical other than the headstamp.

El D,

Thanks for the heads up. I do believe that I've incorrectly associated SAAMI with the ammo manufactures election to cover their A$$ as a joint effort. As Mike Venturino says in the Nosler book the +P is the manufactures attempt to load to higher pressure.

I don't have a listing of SAAMI standard pressures. What I have is Loadtech listed max pressure. What I was told by the Loadtech Rep. when I allowed them to included two of my wildcats was that the program used SAAMI standards and used parent cases for non standard wildcats. They list 54,000psi for the 257 Roberts. Nosler references 58,000psi for the +P so I assumed they were different standards. Loadtech shows 65,000 for the 6mm Rem. but 51,000 for the 7x57. I had assumed this was the standard for the old mil round and simply overrode the pressure.

Loadtech also shows 60,000 for the 280, 30-06 and 65,000 for the 270. Since the 280 was always underloaded this made sense.

Is there somewhere online that I can see the SAAMI psi standard pressures? All this has raised concerns as to exactly how accurate the pressure data I have been using is.

But, back to the original question I still do not believe you need +P brass to load the 257 to it's potential.

Hodgdon's manual recommends a 10% decrease in powder charge if you use +P .257 Roberts brass. I think that Winchester now makes only the +P brass for this cartridge -- at least that's the only kind I've seen from Winchester.

Remington makes the conventional non +P brass in .257 Roberts, and that's what I use. I load it to any level up to the max. (I did, unfortunately, get a bag of the Winchester +P stuff before I understood about the difference. That brass lies unused on my shelf.)

http://www.shootingsoftware.com/ftp/psicuparticle2.pdf
This article lists 54,000 for the 257 and 65,000 for the 6mm. For you Loadtech users the rest of these appear to match except for the 8mm mag.

Can anyone verify Nosler's listing of 58,000 for the 257+p.

quote:

Is there somewhere online that I can see the SAAMI psi standard pressures? All this has raised concerns as to exactly how accurate the pressure data I have been using is

Our friend Steve comes through once more.

http://stevespages.com/saamipressure.html

quote:

Our friend Steve comes through once more

Thank's to Steve and Ol Joe.
Per this article http://www.frfrogspad.com/miscellk.htm
They list a SAAMI standard for both the 257 (54,000psi) and +P (58,000psi). So I'm back to having no clue as to which drove which between the manufacturers and SAAMI. I also don't know if factory ammo for the 257 was loaded even lower than 54,000. Or if in the case of the 280 when everyone makes comments about it being underloaded compared to the 270 was it the difference between the SAAMI 65,000 and 60,000 psi or was the ammo loaded lower than the 60,000.

The W-W SUPER +P 257 brass that I have is 10 to 15 grains heavier than the older Winchester (SUPERSPEED, W-W SUPER) non-+P brass. This brings it up into the same weight range as my R-P brass, none of which is marked as +P. If I remember correctly, Winchester introduced the +P 257 loads at about the same time that they added the 6mm Rem to their product line. (The W-W SUPER 6mm Rem brass that I have is in the same weight range as their 257 +P brass.)

Cheers, Al

gee wiz all my roberts brass has LC63 stamped on it and works great

I bought 100 remington 257 brass last year & lost 80% of them in the pre firing neck sizing.. called remington & they sent me a check for 1/2 my cost.I threw the whole lot in the trash can. I have never had a problem with winchester brass my normal load is 45.0 gr of h4350 & i doubt that is more than a 90% case fill..I have been as high as 48 gr of h4350 with a 117 gr bullet with no pressure signs but I got scared & accuracy went to hell.

It is my understanding that the 257 was downloaded not because of weak actioned guns, but rather because bullets of the period, especially spitzers under .30 calibre, were not that accurate. Ultimately it was decided that a round nosed bullet at reduced velocity was best, so that's how it happened.

The real mystery is -how did it ever reach production in a length less than 3" with long throated chambers? Excluding the old Remingtons, almost all rifles had box magazines of sufficient length to correct this fault. One only needs to look at how they added a block for the shorter round, witness FN or Winchester.