Resizing cases .243 to .260

[DevilDawg]

I was just given 50 new Lapua .243 cases which I want to resize to .260 Remington. My initial plan was to just neck size these cases, but after thinking about it I'm wondering if I need to run them thru a F/L .260 die after neck sizing? Another thought would be to neck size, then load a squib load to fire form them in my .260 chamber.

All thoughts and opinions are appreciated.

 

[JD338]

You should be able to neck size up, load and shoot. Both the 243 Win and the 260 Rem are based off the parent case, 308 Win.
No need for squib loads. Just go with your starting load and work up.

JD338

 

[Luns4d]

I use the Lapua 243 cases in my 260 and haven't needed to FL size. Great brass, you should be able to get 10 or more reloads from them if you don't shoot them too hot.

 

[fredj338]

I also use Lapua brass for my .260ai. I size in a Redding FL die because it has a tapered expander & it's pretty straight forward.

 

[LoneStar]

I much prefer to use .308 WCF Lapua brass in my .260. This gives thicker necks for less radial clearance and potentially better accuracy. Necking up .243 brass results in thinner necks. Using .308 cases means the expander does not need to be tapered.


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[wingnut]

I've had plenty of W-W brass in 243 so I just necked up in a 260 die. I've never needed to worry about thick necks or neck turning. YMMV!

 

[fredj338]

I much prefer to use .308 WCF Lapua brass in my .260. This gives thicker necks for less radial clearance and potentially better accuracy. Necking up .243 brass results in thinner necks. Using .308 cases means the expander does not need to be tapered.
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I've tried necking .308 down but the necks are way too thick in my chamber. 7-08 will work, but no advantge there. I like the Lapua brass but identical loads shoot just about the same if I switch to RP260 brass.

 

[FOTIS]

Size them up to 6.5 mm it is only 1/2" mm up.

 

[ranger140892]

Yep, size em up, and trim em. I've done it with Winchester brass.

 

[LoneStar]

I've tried necking .308 down but the necks are way too thick in my chamber.....I like the Lapua brass but identical loads shoot just about the same if I switch to RP260 brass.

I guess it depends on your accuracy requirements and your chamber. The thicker necks from the .308 cases are a perfect fit in my chamber, fired necks are just 0.001" larger than when loaded. The necks are unifirm in thickness too, unlike the WW and RP caes I've tured, which have necks with poor concentricity. If you are happy with 1 moa accuracy then I doubt it matters, but for consistent 1/2 moa aggregates it does.


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[Cassity260]

The last brass I bought was Win 243...It sized just as easily as Rem 260 brass. + $2.00 /100 cheaper and no shipping.

After sizing you just have to trim to length 2.025" to get them all even.

AC