Neck up...or neck down?

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foxbat

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I have a Tikka Varminter in 260Rem that shoots very well ( Don't all Tikka's!)

I want to use Lapua brass...

Is it better to buy .243Win. and neck up...
Or use .308Win. and neck down.

I realize that necking up leaves a 'donut' of brass at the junction of the neck and shoulder, and I would like to avoid having to turn my brass.
Is there any big deal about leaving the donut in place and simply shoot it as is?

Comments?
 
Been a few years since I've done much of that sort of case forming but I always liked to expand the necks rather than squeeze them down.

Start with them thin and you won't have to worry about the necks thickening as soon It just always went smoother for me that way. I'm sure that there are plenty of people on here with more experience than I that will chime in.
 
I assume you are building this as a precision rifle?

If so....why would you not want to neck turn your brass? I currently have 300 Lapua .308 cases awaiting neck turning before I run them into a 260 die for an upcoming build.

If these are for hunting rounds I don't think the donut will affect how hard the deer falls. As long as the rifle is shooting to your expectations (MOA, Sub MOA) then all is good.
 
If you fire form the .243 brass in your .260 chamber, then run it through a sizing die with a .294" bushing, (Lapua .243 necks are .015" thick) and bump the shoulder .002", you should be able to avoid the donut. If the donut appears, neck turn the brass to leaving 80% of the thickness (.012"), and cut .02" into the shoulder. This will mean getting a .288" bushing.
 
All I do is run my .243 Lapua brass through a Hornady New Dimension 6.5 neck size die and you're ready to rock. It will be a little cheaper than buying a bushing die and it works just as good.
 
243 to 260

I just necked up some 243 to 260 this afternoon it was brand new Win brass ,used Imperial Wax in the neck and case lube pad on the body and voila ,it worked like a charm. No dents or splits . BTW I use RCBS f/l size die .
 
necking up...

prevents reaming. You might consider steping up gradually. Like the 308 to 243... I had to use a 7-08 first.
 
Same - I'd neck up, F/L die, and fireform. If you're really picky or need the best accuracy possible, then you can measure neck thicknesses, turn if needed and so on. It's about 21 thou up with the .243 brass as opposed to necking down app 44 thou with the .308 - less work stressing and less brass to push around.
 
I neck down. I want to neck turn so I can control the thickness of my brass. I want a neck of 14 to 15 thou thick that is also concentric (not usually possible when necking up). I want to put the shoulder exactly where my chamber desires it without worrying about the donut - if your chamber is per SAAMI spec, you will have to push your shoulder back and you will get heavy brass in the base of your neck.

I want to just cut the base of the neck to reduce any chance of brass build up early in the case life cycle.

For the little time it takes, I want my competition brass to be as good as I can make it.

Oh by the way, if you run your 260R hot, you will be neck turning after a few firings so you may as well get used to it.

For hunting, I would just get some Rem brass and put meat in the freezer.

Jerry
 
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