Long story short, bought 50 mixed headstamp .257 Roberts brass at a gunshow a while back. Tossed it in the brass drawer and forgot about it until today. I separated the brands and ran them through the FL RCBS resizer. Out of the 20 Winchester, I “lost” three due to the brass separating at the tip of the neck. Now I am no reloading pro but I do know the pointy part of the bullet goes up, so I know a little.....but I have never had brass issues like this before.

I thought I might have a rough spot on my expander ball but I checked it and it appears ok. As part of my reloading ritual I sparingly smear a little lube inside the neck with a Q-tip so the expander is not going through “dry”

Any ideas? Dies out of adjustment? Crappy brass?

your brass also has the band above the base. I always took that to be the beginnings of case head separation. Could be wrong but I think that brass may ave been reloaded a few times ?

It might need annealing. I've seen them crack in line with the neck, but not that ring. I guess anything is possible.

That is a possibility as I don’t know how many times it was fired.

I gave them the paperclip test and didn’t feel a stretch groove and I seated a primer in one to see if it would fall in or If it needed some pressure to seat (it did).

I’m thinking that ring is a sizing ring

In all my years of reloading, I have never seen a neck split like that.

I am seeing a possible irregularity

Took a closer look at the remaining Win brass and then opened a brand new bag of Win .257 brass and looked at a new one

On the “old” brass there seems to be a ridge just below the tip of the neck, I don’t see this ridge on the new one. Don't know if this has a bearing or not.

From left to right, old, old, new.

Doubt it will be but check brass length, I have never experienced that

Try to size some 'other' brass and see if you get the same issue (as in not part of that mixed purchase). If you do, it's an equipment issue - if you don't, it's a brass issue. Personally, I'd toss the entire batch as there is no way to be 100% sure what the issue is and it's not worth the risk. But that's just me, I'm risk adverse when it comes to loading.

You must have a minimum measurement of bullet diameter inside the case mouth. So, you need .257" of bullet length inside the mouth. I would trim those back quite a bit and see what happens on the next firing.

Yep, trim em. I have accidentally trimmed cases way too much, but it didn’t hurt accuracy.

Based on recent past experiences with Winchester brass it’s just plain ole crappy brass. Use the ones that work and toss the ones that don’t. I have seen Winchester White box factory ammo split on first firing.... not the neck either the body of the case!

FTWshooter,

Is the headstamp of the problem brass 257 Roberts? Or is it stamped something else? It almost looks like the brass was formed from a different round into 257 Roberts. If it's different, it appears that the shoulder of the previous brass is now in the neck and this is the spot where it's separating. I have seen this before. But it could be just crappy or over used brass.

The shiny ring at the base is from the sizing die stopping there. That is common when sizing and does not indicate that it's a case head separation issue (but it certainly can, if it stretches).

Thanks everyone for their replies. I went ahead and loaded the remaining Winchester brass, it shot ok but had a slight sticky bolt on some of them when chambering (all the brass measured 2.33) so I went ahead and chucked them in the range brass bucket after shooting them. Which was really hard to do because 257 brass isn’t easy to come by!

I have two bags (100 rds) of factory new Winchester to use, Winchester used to be good brass but I have recently read recent articles and reviews that state maaaaybe they are not as good as they used to be. I am too cheap to buy Nosler brass, so I will probably go back to necked down 275 Hornady.

Chris: they were definitely stamped WW Super .257 Roberts. In retrospect I wish I would have saved one of the cases to check the other dimensions of the case, maybe somebody used it for 6mm previously?

Serves me right for buying brass from someone I don’t know, I just got giddy finding Roberts brass in the first place!

You can also neck down 7x57 Mauser brass to form 257 Roberts. I've done this many times.

Oh definitely, I like necking down 7x57 instead of necking up 6mm brass. I like using Hornady brass, it is just that for some reason Hornady does not call their brass 7x57 they refer to it as 275 Rigby ....sounds cooler I guess lol

Out of curiosity have you used Privi brass for this? I see they carry 7x57 at a decent price but have not formed from them before.

I’m betting someone tried their hand at neck turning that brass and took it down too thin.

Privy brass is something to get you out of a bind. If you're wanting top consistency in your ammo (and it seems you do) skip Privi. I would rather neck up, or neck down some higher quality brass before using Privi.

To me that ridge at the end looks like an old factory crimp. Wonder if it is hanging on that?

Like others suggest a good trim and maybe anneal would go a long ways.

275 Rigby is the British name for the 7X57, Imperial measurements ya know. Same cartridge though

I might have some 7x57 and some 257 Roberts brass laying around, neither of which I have the firearms for anymore. I'll take a look in the next few days and if I can find it you can have it. (You'll need to figure out a way to get it, I'm in Houston...)