243 brass to 260

[quillow]

It's my understanding that it's better to neck up than down, correct? For those that neck up your 243 brass to 260 do you turn the necks when your done? I hear part of the shoulder becomes the neck.

 

[KenO]

Maybe I am out of line suggesting, but 7mm'08 Winchester brass is cheap and you wont even feel anything going through the .260 die. No trimming and ready to load.

 

[RonAKA]

Or, wait for the recently announced Lapua 260 brass.

http://www.lapua.com/upload/tuotteet/new-products/lapua260remleaflet2011.pdf

 

[spclark]

I just received my first 260REM-chambered barrel. Had ordered up 100 Lapua .243 cases in preparation, ran 'em over my Sinclair E24 mandrel.

My gut feeling is that such a small portion of the shoulder becomes part of the new neck (I mean SMALL; a 260 case is exactly the same dimension up to where the shoulder begins as a 243, or a 308 for that matter) that it doesn't matter.

Necking up from 243 tends to stretch what portion of the 243's shoulder becomes neck, while necking down from 7mm or 308 tends to compress the entire neck to greater wall thickness, I think the former is the better way to go... unless you want to wait maybe 'till June for that new Lapua 260 to get into distribution channels.

Or buy some Remington or Norma (if you can find any) in the mean time.

I didn't turn my sized-up necks & for the few rounds I loaded (JLK130VLD bottom row, 142SMK top) I couldn't feel a donut. It woulda been on the outside anyway as I expanded the full neck from the inside.

It was really foggy on New Years Eve when I went to the range to break in the newly-cut chamber (barrel had been a 6.5 Grendel before) so I had to be content with 50 yards. I got nearly bug-hole groups with some 5 round strings... see attached. The black dot is a 3/4" paster for scale; I was shooting off a rest but the fog was so bad I had trouble keeping cross-hairs on my aim-point most of the afternoon.

 

[quillow]

Thanks much for the info. Out of curiosity what did you lube the expander with?

 

[Elkbane]

Others may have different experience, but with mine, I started getting doughnuts on the third firing of necked up .243 Win Lapua brass. They were significant enough that you could feel it while seating bullets, some more than others, and sure enough, it showed up as vertical dispersion on target. While I've read where some folks say you can use an expandron to push the excess material to the outside where it can be turned off, I've had limited success doing that. Once I've had donuts, I've been unable to completely remove them, so now I do whatever I can to avoid getting them.

I got better results sizing down Norma 7mm-08 brass, then turning them to just clean up the necks. I get slightly thicker necks that way than with virgin Norma 260 brass, and the neck wall thickness is absolutely true at 13.5 thousandths. I think which way to go is somewhat dictated by your chamber - mine is a little sloppy in the neck (which BTW I think promotes doughnut development) so I need all the neck thickness I can get. The necked down , turned 7mm-08 brass is the best brass solution I've come up with thus far for my 260, but every rifle is an individual and "YMMV" from mine.

ELkbane

 

[spclark]

I'll be looking for donuts as my experience with the necked-up Lapua brass expands. My thinking is that since I use bushing dies, and generally size only about .10" - .12" of the neck when sizing, should brass move up into the neck any donut ought to be far enough down towards the shoulder to be harmless. We'll see in time I guess but at least I know to be watchful.

I turn other brass so it's no big deal to do these to should it prove necessary.

As for lube, I gave up on Imperial (wax, not margarine!) this past season in favor of very sparingly applied RCBS liquid lube: http://www.midwayusa.com/viewproduct/?productnumber=479231

I was having trouble with my Palma brass & asked a reputable Palma 'smith what he recommended. A small-base die and this stuff was his reply, and it works! So I use this lube now; a little bit worked into a Q-Tip then run into each case neck before going into the press.

 

[260Ravage]

I have had very good results necking down lapua .308 brass. After a couple firings I clean-em up on the ouside. Accuracy is excellent. When I can get my hands on new lapua .260 brass,,I'll go for it,maybe,,, It's hard to argue angainst success.