Home Forums Reloading Big Game Rifles making 260 rem brass from LC 308

I was thinking of using some 7.62x51 lake city brass I have for making 260 rem brass.
however I'm wondering if I might run into some problems with the necks being too thick, I don't know anything about neck turning and not set up for it, although I'm not opposed to the idea if someone can tell me how its done. maybe I wouldn't need to. if anyone has any advice on the topic I would appreciate it, thanks in advance

You'll be fine,assuming a factory rifle..............

yes ruger m77MKII

Don't sweat it.............

Maybe sweat it a little.

I have a factory 7mm08 that produces fired necks 0.315" in diameter. The loaded rounds made from sized down WW 308 have 0.310" necks. Good to go.

But dummies made from Lapua and LC Match 308 brass have loaded neck diameter 0.315", the same as the fired WW. I know there is some springback of the fired brass, but that's too close for my comfort.

Make a few measurements before you mass produce.

Not in a Ruger.............

this isn't match brass, its military brass with the crimp

Rock on............

My Douglas long chambered 260 Rem 98 Mauser barrel chamber is .299" diameter rear of the neck and .298" forward.


Putting 97LC brass through the 260 Rem sizer die and then seating a 140 gr 6.5mm bullet, the cartridge neck measures .297".

It looks like it made it, but not so fast.

Shoot the round and measure the inside diameter of the fired case neck.

The fired 308 cases will take a .263" pin gauge , but not a .264" pin gauge. The bullets are .265".

This is possible to shoot, but not a good idea.
There is just not enough clearance.

I wish.
I have so much LC 308 brass lying around.

The only way to do it is to turn some off the necks, and maybe down into the shoulder a hair to get rid of the doughnut.

Usually quite a bit of difference between factory and custom cut chambers.
I had to turn the necks of .308 cases with my first 7-08. I would imagine that going from .308 to 260 would be even worse.

Seeing if a bullet will slide into the fired case is one way of checking for enough clearance. If it will, you're good to go.

Your probably going to be O.K. The important word here is probably and that should never be good enough nor prudent. Re-read Mathman's post as he gives good advice. Measure a fired case, then load a dummy round from the necked down mil stuff, measure it. If the two measurements are too close don't continue.

Why not just buy 260 brass? It's only a couple dollars more than 7mm-08 brass, I think you'd have a lot less problems that way. Using that 308 brass you're most likely going to have to neck turn since you're dropping down 4 calibers and there's a very good chance you're gonna have thick case necks. You can buy 100 rounds of 260 brass for around the same price you can buy a so-so neck turning tool, something to keep in mind.

Okay, I'm shooting the same rifle. I am using LC Match brass for my .260 brass because it's consistent, good price, and I've gotten good accuracy results. BUT!!!! I tried the "size it down and go" method and ran into chambering problems, as in I had shiny spots on my loaded brass after chambering, aka, time to outside turn the necks. I have a Forster trimmer that I use for turning my 6PPC brass, so I just bought another expander in 6.5mm, another neck turning pilot in 6.5mm, and went to town. I don't recall exactly what the measurements were off the top of my head, but I could get them for you with a little work. Colorado, PM me about this, I have an offer for you.

Good wisdom passed along.. for myself..my factory Ruger barrels and my factory Rem VLS barrel take them with no problem... Donut neck and all...

like Clark's 260 Mauser barrel...it must have a real tight chamber.. I'd just ream out the chamber a hair ..

I don't see accuracy problems with any of mine.. plus I have a few more barrels I have to mount any way in 260 on some Winchester actions..

I've offered to just turn Colorado's necks for him down to match what I have done with mine. He's sending them out to me later this week.

This is the type of commaraderie I like to see on the forums here... this is what it is all about..

Selmer, you're a good man!

Oh, it's not completely without benefit - I just moved to Colorado's home stomping grounds - he has hunting connections for me!

And we went in on a Nosler Seconds shipment together to cut the shipping cost, there's mutual benefit here, plus I actually enjoy turning necks on my Forster trimmer. After a day of being mostly with people I can shut the man cave door, set up the trimmer and pretend I don't hear the kids or my wife when I have the power adapter to the drill running. It's therapeutic self-care!

I've reformed a good bit of surplus 7.62 stuff to .243 and only had to skim turn them for more uniform necks, not because they were too thick to safely use.

Necking .308 to .264 will thicken the necks about 16%. Typical GI .308 necks seems to be about .014" so that should make the new necks about 16.25 thou, or .296-.297" loaded. That will be snug but safe. Such a fit will approximate the tight necked chambers BR shooters like for best accuracy.

Mike the neck diameter of a fired case, it will typically be about 1 thou smaller than the chamber neck. Compare that to the neck diameter of your reformed cases. If you are even a thou smaller than fired diameter you will be good to go without reaming or turning the new necks.

If you're going to work with one thousandth clearance with unturned brass you better measure every single one, and and several points around each of those necks. Case to case variation can easily cover .001" when you aren't looking.

I did a little looking around and it seems like the BR guys don't even run them that close with turned necks.