Forming 260 brass from 308... Is neck turning a must?

[jb326]

The title pretty much sums it up... I have read everything from it is absolutely necessary to outside neck turn to it likely not being necessary at all. As I understand it, I can load a round, color the case neck with a Sharpie, and then chamber it to find out if I need to, but I'm a little new to the whole thing as far as brass conversion.

If it is necessary, what is the most economical way to get into neck turning equipment wise?

I would just buy 260 brass, but I have a substantial supply of Federal Gold Medal 308 brass that is free and frequently replenished so it doesn't make sense to not make use of it outside of my 308 needs.

Thanks in advance.

 

[MarinePMI]

Not sure about the .260, but for the 6.5 CM it is. Out of 50, had about 10 that would chamber, the rest (lessons learned) had to have the bullets pulled, primers popped and then neck turned.

 

[Bluejazz]

Form a few, measure the neck wall thickness or load a dummy round and measure to outside diameter.

If it's the same or smaller than a loaded .260 case your good to go without neck turning.

However if the diameter is larger you'll have to remove brass from the neck.

Also the reformed case capacity ( Volume ) may be less that a .260 and should be measured.

You would have to reduce your powder charge as well.

Regards & good shooting,

Steve

Good advice right here.

 

[Bill Larson]

If one does`nt neck turn.The wall thickness of the case neck will vary.Thus making a seated/loaded bullet not concentric with the case body.....

 

[mnhntr]

I use 7mm-08 brass for my 260 and never need to turn the necks but I would bet you will with 308.

 

[jb326]

Thanks guys. So what is going to be my "best" choice in a trimmer, bearing in mind that money is somewhat of an issue.

I've got 400 pcs of brass formed, I guess I need to get trimming... My McRee chassis is somewhere on a big brown truck, an it's going to be time to shoot when it arrives.

 

[jb326]

I measured a few and it looks like my formed cases are running about .295" while loaded Copper Creek rounds are running .290".

I'm loading my Sinclair Intl cart now with trimming gear.

 

[427Cobra]

Well it's your chamber, but 308 brass is .020 too short for 260Rem

 

[jb326]

Well it's your chamber, but 308 brass is .020 too short for 260Rem

How big of an issue is that? Most of the dozen or so cases I measured were running close to 2.025, which is above the minimum trim length in my manuals.

These will be running out of a Shilen barreled 700 and possibly a Tikka T3 Sporter if I'm a good boy.

 

[jcampbellsmith]

Well it's your chamber, but 308 brass is .020 too short for 260Rem

It's not a big deal. Nosler brass comes at 2.010 inches straight out of the box. I typically trim Remington brass to 2.027 inches. Regards JCS

 

[gvanhyning]

Form a few, measure the neck wall thickness or load a dummy round and measure to outside diameter.

If it's the same or smaller than a loaded .260 case your good to go without neck turning.

However if the diameter is larger you'll have to remove brass from the neck.

Also the reformed case capacity ( Volume ) may be less that a .260 and should be measured.

You would have to reduce your powder charge as well.

Regards & good shooting,

Steve

If I were necking down .308 Win to .260 Rem, I would ream the inside of the necks. Necking down that much will typically develop the dreaded donut inside the neck which will affect neck tension.