Neck up or down?

[Warpt762x39]

In my research for potential firearms purchases for the (hopefully) near future, I decided that I want a bolt action rifle in .260 Remington.

It will only be for the range and as a personal challenge to squeeze every bit of accuracy out of each of the rifle, ammunition and myself.

I have noticed that .260 ammunition is kind of hard to come by and it is rather pricey. With that piece of information I have decided that the .260 bolt gun I buy will be fed only handloads.

After that decision I have found another small problem. .260 brass isn't all that common. Bullets are easy to find because of the 6.5x55mm Swedish Mauser rounds.

I have learned that the .260 Remington case is the same basic case as the .243 and .308 Winchesters. The new piece of info that I need is in regards to resizing brass.

Is it easier to neck down the .308 brass or neck up the .243 brass?

I can't recall ever reading any information on the pros and cons of necking either up or down. Any info would be greatly appreciated.

On a side note I had been researching a wildcat round with the same basic problem but in .25 caliber. Anybody have info on the .25 Souper?

[mauser]

The actual sizing is really easy, no more effort than sizing a case of the proper caliber.
I'd personally opt for sizing up the .243 brass.
When you size down a .308 case you're making the diameter .044" smaller, when you size up a .243 you're making the diameter .017" bigger, a lot less of a change.
You have to pay attention to the neck thickness when you size down, the extra brass has to go somewhere and that somewhere is the wall thickness of the neck. If the neck wall is too thick it can generate dangerous pressure by holding the bullet too tight when chambered unless your chamber is loose enough to allow for the extra thickness. The neck can be turned or reamed to proper thickness if needed, but that's an extra step thereby making it easier to use .243.

[Tomcat088]

What Mauser is saying is correct, but I do want to bring up one point. Just because something is easier, does NOT mean that it's "better"; it will all depend on your application. Sometimes when you size up you will be losing some consistency in the brass and you will add a bit of stress to it. When you size down, you have plenty of extra brass to work with, as mention. When you turn the necks down, you will have a more consistent neck that doesn't have the same stress in it that necking up can cause. You can always take metal off, but it's not too easy to add it back on. Just something to consider, sorry that it's not a direct answer.

[mauser]

Originally Posted by Tomcat088

What Mauser is saying is correct, but I do want to bring up one point. Just because something is easier, does NOT mean that it's "better"; it will all depend on your application. Sometimes when you size up you will be losing some consistency in the brass and you will add a bit of stress to it. When you size down, you have plenty of extra brass to work with, as mention. When you turn the necks down, you will have a more consistent neck that doesn't have the same stress in it that necking up can cause. You can always take metal off, but it's not too easy to add it back on. Just something to consider, sorry that it's not a direct answer.

Excellent point Tomcat.
I was focused on this part of the OP:

Is it easier to neck down the .308 brass or neck up the .243 brass?

and I glossed right over this part:

It will only be for the range and as a personal challenge to squeeze every bit of accuracy out of each of the rifle, ammunition and myself.

I have noticed that .260 ammunition is kind of hard to come by and it is rather pricey. With that piece of information I have decided that the .260 bolt gun I buy will be fed only handloads.

If the goal is really to squeeze every bit of accuracy of everything then you would be better served by sizing down .308.

If you don't already have the tools to turn or ream the necks I'll suggest that you look seriously at the Forster case trimmer. As well as being an excellent tool for trimming to length, it's also (with the additional attachments and tooling) an excellent tool to ream the inside and/or turn the outside of the necks.
There are other tools on the market to do the same jobs but I can't give you an opinion on any except the Forster. I have one and I like it a lot, I have no desire to try any other.

[hipwr260]

I have had some luck necking down 7mm-08 brass. I had gotten some from a friend who didn't reload so price was't an issue.

[WVBob]

If you want new brass, Midway has it. Norma for $22.99 for 20, Remington $44.99 for 100. I understand wanting to try to "make" your brass. But you will have neck issues any way you go.

[Tomcat088]

If you're going to use Norma Brass, I've heard LOTS of people that are annealing the .260. You may or may not want to do it. Norma brass is great, but it's also known for not exactly being the most durable or tough; that's why alot of people anneal it. Anyway, just something to think about.

[Bama Man]

The 260 Remington is also known as the 6.5 A-square and it would have been designated that if Remington had not submitted the 260 Remington also.
It was originally a necked down .308 and became a very popular wildcat cartridge until Remington made it their own and SAMMI went along with Remington, other than A-square.
As far as necking: keep it to safe spots where the police or parents can't find you. oh, wait, wrong kind of necking, I have a 256 Newton that again is a wildcat cartridge, and can be formed from 30-06 cases.
HOWEVER; I have been advised by the man that built the rifle,who is an older wildcatter, that it is more preferable to produce the cartridge from 25-06
cases instead, as the brass needs to go somewhere, and it is better to stretch the kneck than to squeeze it down and ream it.
Just my 2 cents, and what I was told. I'd stretch out the .243. and, check Graf and Son for brass, they often have great sales on brass, but even if they don't, I have never seen them oversold in what I bought.
My Newton is like your building, a fun bench rest machine, built for accuracy.
My Newton is a 1500 Smith-Wesson, scoped out with a single power 4X32
Leopold.
Unfortunately, it actually was a gift to my wife by my gunsmith friend, But she lets me go out and play with it.

[Tomcat088]

Originally Posted by Bama Man

The 260 Remington is also known as the 6.5 A-square and it would have been designated that if Remington had not submitted the 260 Remington also.
It was originally a necked down .308 and became a very popular wildcat cartridge until Remington made it their own and SAMMI went along with Remington, other than A-square.
As far as necking: keep it to safe spots where the police or parents can't find you. oh, wait, wrong kind of necking, I have a 256 Newton that again is a wildcat cartridge, and can be formed from 30-06 cases.
HOWEVER; I have been advised by the man that built the rifle,who is an older wildcatter, that it is more preferable to produce the cartridge from 25-06
cases instead, as the brass needs to go somewhere, and it is better to stretch the kneck than to squeeze it down and ream it.
Just my 2 cents, and what I was told. I'd stretch out the .243. and, check Graf and Son for brass, they often have great sales on brass, but even if they don't, I have never seen them oversold in what I bought.
My Newton is like your building, a fun bench rest machine, built for accuracy.
My Newton is a 1500 Smith-Wesson, scoped out with a single power 4X32
Leopold.
Unfortunately, it actually was a gift to my wife by my gunsmith friend, But she lets me go out and play with it.

I just wanted to point out one thing. There is a difference between reaming the necks and turning them. When you turn the necks, you are at times taking off a pretty significant amount of brass.

[Bama Man]

Originally Posted by Warpt762x39

In my research for potential firearms purchases for the (hopefully) near future, I decided that I want a bolt action rifle in .260 Remington.

It will only be for the range and as a personal challenge to squeeze every bit of accuracy out of each of the rifle, ammunition and myself.

I have noticed that .260 ammunition is kind of hard to come by and it is rather pricey. With that piece of information I have decided that the .260 bolt gun I buy will be fed only handloads.

After that decision I have found another small problem. .260 brass isn't all that common. Bullets are easy to find because of the 6.5x55mm Swedish Mauser rounds.

I have learned that the .260 Remington case is the same basic case as the .243 and .308 Winchesters. The new piece of info that I need is in regards to resizing brass.

Is it easier to neck down the .308 brass or neck up the .243 brass?

I can't recall ever reading any information on the pros and cons of necking either up or down. Any info would be greatly appreciated.

On a side note I had been researching a wildcat round with the same basic problem but in .25 caliber. Anybody have info on the .25 Souper?

The .25 "souper" you have heard of is probably the 250 Humdinger, found in the book, Cartridges of the World.
It is a .243 necked to .257, with minimum body taper and a 45 degree shoulder angle which is similar to an Ackley shoulder.
The case is easily made by necking to .257 and fire forming.