Home Forums Reloading Big Game Rifles 257 Roberts +P brass vs. regular brass question

Is there any difference that would affect my hand-loads from some reason? And in what way? Too much pressure? My load recipe has been the 90 gr. Barnes X bullet/46.5 grains IMR 4350/Remington 9-1/2 for a Winchester Model 70 FWT. My last batch of brass had been loaded so many times, the necks started cracking after every shot. I bought some new 257 Roberts brass (Winchester) and noticed the headstamp said +P. If I use my old load recipe, will it be too much pressure? Thanks!

I do not think so. I reloaded a similar load using both non +P and newer +P stamped brass no issues. I believe that SAMII upped the pressure for 257 Roberts, hence the +P stamp. Others may know more than I.

Take a few old cases and some of your new, resize, weigh, fill with water, and weigh again. Should give one some idea on whether volume is the same or not.

Many years ago, when the +P .257 pressures were first introduced by SAAMI, I bought some Winchester .257 brass without noticing it was stamped +P. Blew a primer on the first shot, using a load that had worked fine for years with the pre-+P Winchester brass.

Of course, back then I was more prone to pushing limits. But weight the +P brass and it was significantly heavier than the standard Winchester.257 brass. Have always wondered why, since even the +P SAAMI pressure for the .257 is only 58,000 PSI, which is pretty mild.

I do not know if the +P brass is still heavier, because have moved on to other brands.

I've always used non +P brass for my 257, but didn't realize I was getting +P this time. I bought it off of guy I know in an unopened bag of new Winchester brass. The bag was not marked +P. I pulled the bullets from the last 30 rounds of loaded rounds and transferred them over into some new primed +P brass. Hopefully, I'll get t the range this weekend to give them a try.

Dub,
If your primer pockets are staying tight enough, and the necks cracking is the thing limiting your case life in your Roberts, you should really look into annealing your necks on those cases every three loadings or so. They should last a really long time if you do that. It's very easy and there are a couple threads on "ask the Gunwriters " now about how to do it on the super cheap.
I've never used anything but Federal brass with the +P headstamp in my Roberts so I can't give you any comparative experience on that question.
Cheers,
Rex

I have weighed Nosler +P and Remington brass and found no difference in weight.

Rex,

Thanks for the suggestion. I've never tried annealing cases and I've been reloading for close to 40 years. I've never used +P brass either, but this is all I could find. The 257 Roberts brass that I had been loading is several years old. So old, that I don't remember when I purchased it and can't even remember how many times it's been reloaded. I've been a little lax in keeping track of that I'll admit, but I'll bet it's all been reloaded at least 8 times. I'm pretty sure I thought I could get one more loading out of them, but it obviously wasn't meant to be.

I pulled all of the bullets, dumped the powder into a hopper and reloaded the same charge weight and seated the old bullet. I'll hit the range this weekend, weather permitting and see how it works.

I’ve never used anything but Remington brass in my Roberts however I did recover a few Winchester +P range brass at our range last year. Out of curiosity, I took them home and weighed them. They actually weighed less than my “regular” Remington brass. So this begs the question. Has Remington been making +P brass all along without publishing a bunch of hype over it?