Necking 308 to 260Rem. procedure?

[Lightload]

What's the procedure for making good 260 brass out of good 308 brass. What I''m thinking about specifically is turning and/or reaming the necks. Do you neck turn first, then size then ream.....size then neck turn then ream???? I can see different sequences that may work well but what sequence or procedure so you guys use?

 

[OldManTA]

Put the 308 brass in a FL 260 Rem. die after lubricating with Imperial wax or similar and form the brass. Most of the 260 rounds I shoot now started out as 308 Win brand brass. If you want to turn the OD's or ream the ID's that is up to you but do it after firing a time or two.
Tom Alves

 

[mshelton]

If you have access to a 7-08 FL die you might consider running them through that first then the 260 one, I've had better luck stepping necks down as gradually as possible but ymmv.

 

[ebb]

Start with 243 brass and you don't have to worry about the necks ever. Size in a 260 die and CUT OAL as 243 will make longer brass than 260 (too long, ask how I know). I don't understand the poster that said to turn necks after fired twice. If the necks are too big they are too big from the beginning, and in a tight chamber will way over pressure a gun.

 

[mshelton]

The turn twice thing might have been meant to clean them up, I've always done that.

Virgin brass, rough cut then finish cut, fire, then another finish cut. May not be necessary but I feel it helps with any irregularities.

 

[Romulus]

I go from .308 to 7-08 and then down to 260 Rem. I then fireform with cotton pellet projectiles from Brownnell's and (forgot you're not going to AI lol) then neck turn. I can't remember if I annealed before fireforming or after neck turning. I'll have to check some records when i get home.

Please follow up with your chosen procedure and results!

 

[mshelton]

If you're buying 308 brass you might want to look at the Palma Lapua 308 brass, has a small primer pocket in stead of the large.

 

[barefooter56]

Lightload,
To take .308 down to .260 Try using a standard Redding .260 FL Die set. Take the seater plug out of the seating die and use it as your form #1 die then run it through the full length die. Check the neck wall thickness before you size the brass down. Then check it again after the .260 case is formed. Unless you know what the neck diameter of your chamber is and the formula to find what the neck wall thickness should be you may want to turn the neck of the.260 brass to the neck wall thickness the .308 was IF it thickens up. Use a ball end micrometer for this NOT CALIPERS. Necking up from .243 would be easier but you may need to run your brass through a Redding body die set up touching the shell holder to knock the shoulder back so the cartridge will chamber. The expander ball in the .260 will pull the neck and shoulder up in many cases which is why you may have to do this step. Replacing the steel expander ball with a carbide unit may help this also. Use a L.E Wilson cartridge case gauge to check your work. Or you can sell the .308 brass and get the LAPUA .260 BRASS and be done . If the .308 brass is not new you may have to anneal it before necking down. If you do have to neck turn . New brass is best to turn. Once fired is most you can have on a cartridge case and still get a good result neck turning. The Redding standard dies are the only ones to use for this that will work that I know of because the standard seating die mimic's their Form dies.
Example of the formula to find what your neck wall thickness should be if you know the neck dimensions of your chamber is :
.292 neck diameter in the chamber minus (-) .001 = .291
.291 - .264 ( bullet diameter) = .027
.027 divided by 2 = .0135 is the MAXIMUM neck wall thickness that will fit in the chamber. suggest you turn the neck wall thickness to .001 under this (.0125) to give the case neck a little more room to expand to release the bullet as a safety to prevent excessive pressure.
Hope this helps,
Take care,
Phil Hoham
Berger Bullet Tech

 

[Lightload]

Great info! Thanks guys!

I don't have access to .243 brass but I can see where it would be easy to work with.

The 308 brass I have access to is once-fired (bolt gun) Federal. After popping the primers out and tossing the cases in the tumbler for a bit, they come out absolutely pristine. I'll try using the 308 brass I have first but buying the SR primed Papua brass is on my short list.

Found out a couple days ago that there's a five or six month wait for my barrel so a lot of prep work I was going to do will be on hold for awhile.

Thanks again for the replies!

George

 

[Clint M]

Do you have any factory 260 brass at all to compare your formed brass to ? A step down as mentioned either using your seating die with seater plug removed or 7mm-08 is helpful, and will reduce problems, effort etc. The main thing to worry about is finished neck diameter with loaded bullet if there is not sufficient room between the outside neck of case and chamber it can "pinch" the bullet causing pressure to spike. If your using a factory chamber you may not have to turn necks, but I would check, double check and check again after forming with loaded bullet in dummy round, and after firing. As posted above use a good case lube I prefer Royal Case and Die Lube, but Imperial is a close second, you can google/search using a fired case in your gun to get an idea of the neck diameter of your chamber....make sure you measure neck diameter from case mouth back to shoulder (don't just measure in one place)... I hope this helps I have formed 260,7mm-08 from 308 without problems I try to start with good 308 brass when putting the time and work into doing it.

I have ~500 speer nickle plated primed I purchased years ago I would be willing to part with a few if you just need to get by until you can purchase some brass.

 

[Erik Cortina]

What's the procedure for making good 260 brass out of good 308 brass. What I''m thinking about specifically is turning and/or reaming the necks. Do you neck turn first, then size then ream.....size then neck turn then ream???? I can see different sequences that may work well but what sequence or procedure so you guys use?

I'm going to tell you the best way to end up with .260 brass out of .308 brass.

Take all your .308 brass and sell it, use money to order new Lapua .260 brass.

 

[BradY]

308 palma cases make great 260 cases. They really handle pressure well and last for ages. CCI450's are best primers I found for lighting up that size powder column.

Start with new 308 palma or annealed used cases. Neck to 7-08 in a non bushing style FL die. Then do the same from 7-08 to 260. You will need to turn your necks down and trim as well. Did this for 260 improved cases and they were unbelievably good. If I was going to do a 6.5mm again and want to use small primer cases I would just do a normal 6.5x47L though.

 

[ta406]

I just anneal, then use a standard RCBS 7mm-08 neck die with the expander ball removed, then run them through my Redding 260 FL bushing die. Pretty simple actually. I don't have to turn the necks in my chamber. This is using WRA 67 brass. But like others have mentioned, keep an eye on loaded neck diameter.

 

[tipper999]

7mm-08 neck die or FL die / expander ball if you don't it will roll the neck in to much, then through a 260 die neck or FL / expander ball, there is no need to size the body if it is new Brass. The necks will be a little short, Fire-Form a little hot & will be good to go. I had GREAT results with Palma Brass, the necks are a little thick but they work really good.

 

[tipper999]

What's the procedure for making good 260 brass out of good 308 brass. What I''m thinking about specifically is turning and/or reaming the necks. Do you neck turn first, then size then ream.....size then neck turn then ream???? I can see different sequences that may work well but what sequence or procedure so you guys use?

I'm going to tell you the best way to end up with .260 brass out of .308 brass.

Take all your .308 brass and sell it, use money to order new Lapua .260 brass.

Sorry you are right & lazy , it is fun to work the BRASS a little

 

[Erik Cortina]

What's the procedure for making good 260 brass out of good 308 brass. What I''m thinking about specifically is turning and/or reaming the necks. Do you neck turn first, then size then ream.....size then neck turn then ream???? I can see different sequences that may work well but what sequence or procedure so you guys use?

I'm going to tell you the best way to end up with .260 brass out of .308 brass.

Take all your .308 brass and sell it, use money to order new Lapua .260 brass.

Sorry you are right & lazy , it is fun to work the BRASS a little

In that case make the brass out of 30-06!

 

[tipper999]

What's the procedure for making good 260 brass out of good 308 brass. What I''m thinking about specifically is turning and/or reaming the necks. Do you neck turn first, then size then ream.....size then neck turn then ream???? I can see different sequences that may work well but what sequence or procedure so you guys use?

I'm going to tell you the best way to end up with .260 brass out of .308 brass.

Take all your .308 brass and sell it, use money to order new Lapua .260 brass.

Sorry you are right & lazy , it is fun to work the BRASS a little

In that case make the brass out of 30-06!

that is just stupid

 

[Erik Cortina]

What's the procedure for making good 260 brass out of good 308 brass. What I''m thinking about specifically is turning and/or reaming the necks. Do you neck turn first, then size then ream.....size then neck turn then ream???? I can see different sequences that may work well but what sequence or procedure so you guys use?

I'm going to tell you the best way to end up with .260 brass out of .308 brass.

Take all your .308 brass and sell it, use money to order new Lapua .260 brass.

Sorry you are right & lazy , it is fun to work the BRASS a little

In that case make the brass out of 30-06!

that is just stupid

But making .260 brass out of .308 when .260 is plentiful is smart?... I see.

 

[ShootDots]

Erik, if a shooter is inclined to make .260 brass out of .308 brass would only make sense IF the reloader wants to use Lapua Palma brass. That brass can really hold pressure and you can make substantial gains in velocity over "regular" .260 brass. If it is worth it to a reloader to do that, it is a valid reason to go that route. However, if they are going to stay with regular L/R primer brass, then that makes no sense..

 

[Erik Cortina]

Erik, if a shooter is inclined to make .260 brass out of .308 brass would only make sense IF the reloader wants to use Lapua Palma brass. That brass can really hold pressure and you can make substantial gains in velocity over "regular" .260 brass. If it is worth it to a reloader to do that, it is a valid reason to go that route. However, if they are going to stay with regular L/R primer brass, then that makes no sense..

I agree with you Ben, but it's still a lot of work. It would be easier to build a .260 AI and run it at .260 speeds and brass would last forever! Have you ever heard of a .260 AI Ben?