260 Remington from ???

[CPL Lou]

Since 260 Remington brass costs about $1.10 each, I've been wanting to form some from another case.
Preferably 308 or 7mm-08 brass.
Which would give better results and do I need to do any neck turning (something I don't relish doing) when I'm done resizing ?
Any help would be appreciated !

CPL Lou

[EDG]

Lou
You need to measure the neck of your chamber to find out how large it is first.

Take a fired case and drive a tapered punch or tapered expander ball into it until it is about .030 larger in diameter than a loaded round.
The neck can be trumpet or funnel shaped.

Push this case into your chamber with the bolt and extract it. The chamber neck will have necked down the edge of the trumpet mouth. Measure this diameter for your chamber neck diameter. Repeat about 5 times to make sure you are getting consistent results. Write down the diameter of your chamber neck.

Get a few sample 7.62 cases and neck them down to .260 and seat a bullet in the neck. Measure the neck diameter all around with the seated bullet. To be acceptable it should be at least .003" smaller than the chamber dimension. Check 25 or 30 cases before proceeding to do hundreds. Try the samples in your chamber to make sure your measurements are correct.
If you don't want to turn cases you might offer to swap some brass to someone that can turn them for you.

If you neck down some cases they will need to be annealed to keep them from cracking. If you find that the necked cases are too thick and you want to skip turning consider expanding .243 brass and using it.

If you would like a sample of your brass turned I would be glad to turn a few for you to play with and shoot.

[CPL Lou]

Thanks for the quick reply !
My only worry with necking up 243 brass is that it won't stay concentric.

CPL Lou

[EDG]

Well you have no guarantee it is concentric to begin with.
How ever a long tapered expander tends to expand it evenly.
Bench rest shooters expand a lot of brass and most turn it to get it even.
I expand .222 Rem Mag brass to 6mm to shoot in a 6X47. If I turn it at all I only clean up the thick side and that is only about .0005 taken off to remove brass about half way around the neck.

If you are committed to worrying about concentricity then going the route of cheap brass is the wrong way to do it. If you are really concerned about utmost accuracy and uniform necks then you might want to consider a small lot of Lapua brass to learn with. If it helps you can buy more if not you can form GI brass and neck turn it for much less money but more work.

The guys at the accurateshooter forum beat this subject to death every week.
Some of them go as far as forming the Lapua .308 Palma brass because it uses a small rifle primer and it will withstand higher pressure with the thicker case head.

Thanks for the quick reply !
My only worry with necking up 243 brass is that it won't stay concentric.

CPL Lou

[Idaho Sharpshooter]

What EDG says, plus one. The easiest answer, although not the cheapest, is to just buy some Lapua or Norma 260 brass. It is such good quality, you do not need to buy 300+ like you would with Win/Rem to get a hundred good ones.

[GRUMPA]

I make those from 7.62 LC brass (308) and go through a lot of them at times. A person can use what I call domestic brass, like FC, Win, R-P etc with the understanding that either turning or reaming the neck is required.

I've done so many over the years about the only thing I would point out is that the chamber itself isn't always to spec. Here's the S.A.A.M.I. spec drawing and notice the .297 diameter for the neck, not all chambers are the same. Seems when they ream the chambers diameters can and will be all over the place.

Link to the drawing in my VS page: http://castboolits.gunloads.com/show...m-308-LC-brass

[Texas by God]

I make .358 Win from .308 in one stroke with old CH dies. .243 to .260 should be a breeze. I would anneal them then load. Best, Thomas.

[Solothurn]

Making .260 brass from Winchester 7mm-08 brass worked great for me, without neck-turning or annealing. I haven't tried anything else.

[robg]

243 sounds the way to go 6mm to6.5mm less likely to thick necks rather than squeezing 7mm down

[reed1911]

I use 7-08 as well with no issues. I have a bunch of 7-08 brass if you need some. New, Winchester, 50 count bags 27.00 + S/H.

[CPL Lou]

Thanks for all the input guys !
I'm going to try a little of both 7mm-08's and some 243's.
I have a few cases of each on hand now courtesy of a friend.
I'll measure my outside neck diameters with a bullet seated in them and compare them to my Lapua handloads.
Lapua brass costs about $1.20 a case...EXPENSIVE !
What I'm trying to do is find a reliable supply of cases that I can convert. A couple of months ago 260 brass was made of unobtainium.
Don't want to run out of cases again !
Thanks again folks !!

CPL Lou

[John Boy]

Parent case

	.308 Winchester
Bullet diameter	.264 in (6.7 mm)
Neck diameter	.2969 in (7.54 mm)
Shoulder diameter	.4539 in (11.53 mm)
Base diameter	.4705 in (11.95 mm)
Rim diameter	.4728 in (12.01 mm)
Rim thickness	.0539 in (1.37 mm)
Case length	2.035 in (51.7 mm)
Overall length	2.800 in (71.1 mm)

[tygar]

I form a lot of cases & forming up is usually easier (usually no need to turn necks).

The only problem with going up I have found is if your cases turn out to be shorter. e.g. 375H&H to 450 Watts, so use 416RM.

With the short cases never had the problem.

If you have good brass to start necking up should not change the concentricity of the brass when necked up.

Personally I would try 243 - up, & 308 - down, even if you have to do some turning, you will know you have round necks. Then see what works the best for your gun.

Don't know about 7-08, but it's closer to 6.5 than 308, so that also sounds like a plan & maybe no turning.

But I would guess 243 or 308 is cheaper, brand to brand than the 7-08, but who knows.

[Mk42gunner]

I have never made .260 Remington brass, but I have made a bunch of 6.5-06 brass from new WW .30-06 cases. One pass through the RCBS sizer die (with appropriate lube) and I was good to go.

I necked down .30-06 instead of expanding .25-06 in case someone else got hold of it and tried to chamber it in the smaller caliber. I can hear it now "But it says .25-06 on it!"

That is one reason I do like milsurp brass for cartridge modifictions, no headstamp to argue about.

Robert

[357Mag]

CPL Lou -Howdy !If you want consistent neck wall thickness, and intend to still have a .011" thick neck wall; you might have to go w/ use of .358 Win cases necked-down to .264" calibre. In that way, you can start off w/ necks that have some extra margin in their thickness, to permit neck turningdown to the desired neck wall thickness.With regards, 357Mag

[runfiverun]

most of the 358 win brass I have measured lately is just 308 win head stamped 358.
if you neck it down you end up with a 308 case and the same thickness.

if I am looking for good brass from domestic brands I do sort through it and weight sort.
then neck down.
I want to be able to remove material for better fitment.
when you size up the material doesn't expand perfectly it has thick and thin spots.
most guy's then turn off the high spots to even things out. [for better neck tension ya' know]
this then makes the brass even less capable of supporting the bullet in a straight line with the center of the barrel.

unfortunately without measuring the rifle I don't even know what I'm looking for, I'm just making stuff.

[country gent]

Cases tend to get thinner necking up and thicker necking down. Ive made .243 from .308 and got snug to tight necks and had to neck turn it. On a wildcatt I made up necking down 300 wsm to 6.5mm I had to neck ream and turn for best results but this case actually was shortened to where part of the original shoulder was neck when formed. On my 357 herrets the necks actually get about .001 thinner in wall thickness going from 30 cal to 357. There is only so much brass in a case to work with and sizing up the extra size has to come from some where and sizing down it has to go somewhere. Look at the thickness of a rubber band and then stretch it and watch the thickness. When resizing brass flows in a pattern due to stresses, memory, and force. Also I recomend checking concentricity of the brass before starting since if its not concentric to start with its probably not going to get any better reforming it. If possible check at the neck and in the body close to the case head both.

[CPL Lou]

After consulting with SWMBO, it looks like I'll be investing in some case neck turning tools and a case annealing tool.
I was hoping to avoid doing this, but it will make my supply of 260 Rem brass a little more secure.

Thanks for all the information you folks shared with me concerning this project!

CPL Lou

[Texas by God]

Academy sells .243 Monarch (Privi-Partizan) ammo for about $14/20. Buy a box, put on your eye and ear protection and shoot them out of your .260 into a close backstop. Voila-great .260 brass at a great price. We used to make .250 Sav from 22-250 and .35 Whelen from 30-06 this way back in them days. Kinda fun shooting KEYHOLE groups at ten yards!

[Idaho Sharpshooter]

Is it that much more expensive?