Thread: Lapua 308 brass resizing to 260

Hi all,

Would appreciate some feedback on the following:

Have 145 rounds of new Lapua 308 brass and wondering, given the component cost and supply issues, does it make it worth the effort to resize down to 260?
Gave up the 308 over a year ago and am starting load development on the 260 so no chance of confusing the two and I have 100 new Lapua 260 brass as well to start with.

Being a beginner in this I’m hesitant to go down this road if it would be better to sell or swap what I have and stick to the basics.
Also, I like to keep things neat and tidy and mixing headstamps offends my sensibilities some how😬😬

Cheers, Sidetrack

If you have 100 new .260 I wouldn’t bother resizing the .308 but it can be done iv done it with ease and it was .308 lapua down to .260 maybe keep it for later if you end up needing it it’s easy to neck down

Just go for it. There is nothing to it. If its new Lapua brass it will be annealed and soft. Use a high quality lube such as Imperial wax and run it through a 260 Full length die. Yes it will have slightly thicker neck brass but that is really no big deal. If you want to go back to 308 have it annealed and run an expander though it and you are back were you started.

What ^^^ said but I’d also give it a light neck turn to just cut into the shoulder a touch to stop the chance of it developing a donut.

After you have sized it down to 260 anneal the necks. I sized 7.62 to 243 and, at first, did not anneal and the necks cracked.

Sell the 308 brass and buy 6.5mm projectiles

The shoulder heights on all .308 sized cases are all slightly different to stop people chambering smaller calibers in larger chambers ie .708 in .308 etc.

.308 is 1.7118 and .260 is 1.776 if you neck turn it will be easier to do it with a .308 mandrel and then neck size down to .260 and blow the shoulder forward on first firing, with the bullet seated into the lands to get a good form/reduce stretch lower in the case. Usually you full length size new brass before you neck turn it ideally using a full length non bushing die e.g see https://www.accurateshooter.com/tech...urning-basics/

You may (or may not) be able to full length size .308 brass easily down to .260 for neck turning using a .260 full length non bushing die due to the shorter case not bottoming out in the die. I converted a heap of .308 lap to .708 with neck turning as I got some cheap now I just buy norma .708 way less hassle

I have done it. If you start with thick necks like Lapua ( @15 thou) by the time it's at .260 the necks will be around 17 thousands plus.
Then you will need to neck trim. Even if you get away without it, the walls will be uneven and you have turned good saleable brass into something else. If you like we can swap brass. I am thinking of turning my .260 into a .308
By the time I sell the projectiles and brass the barrel change will be free!

Originally Posted by yerimaginaryM8

The shoulder heights on all .308 sized cases are all slightly different to stop people chambering smaller calibers in larger chambers ie .708 in .308 etc.

.308 is 1.7118 and .260 is 1.776 if you neck turn it will be easier to do it with a .308 mandrel and then neck size down to .260 and blow the shoulder forward on first firing, with the bullet seated into the lands to get a good form/reduce stretch lower in the case. Usually you full length size new brass before you neck turn it ideally using a full length non bushing die e.g see https://www.accurateshooter.com/tech...urning-basics/

You may (or may not) be able to full length size .308 brass easily down to .260 for neck turning using a .260 full length non bushing die due to the shorter case not bottoming out in the die. I converted a heap of .308 lap to .708 with neck turning as I got some cheap now I just buy norma .708 way less hassle

Sorry but this is not true. To my knowledge all of the .308 family of cartridges have a length to shoulder of 1.56" (39.62mm). The length to the base of the neck differs due to changes in diameter. A new 7mm-08 case will chamber in a .308 chamber etc.
GPM

Originally Posted by grandpamac

Sorry but this is not true. To my knowledge all of the .308 family of cartridges have a length to shoulder of 1.56" (39.62mm). The length to the base of the neck differs due to changes in diameter. A new 7mm-08 case will chamber in a .308 chamber etc.
GPM

I thought it was the other way round, i.e. lengths were different to prevent chambering larger calibres in small chambers. I much rather fire a 243 round in a 308 rifle than vice-versa!

According to the CIP standards, all the 308 family are the same measurement to the base of the shoulder (1.5598 inches), but the measurement to the top of the shoulder/base of neck varies (which makes sense as all have the same shoulder angle, so shoulder continues further to narrow down to a smaller diameter):
243 1.8043
260 1.7756
7mm08 1.7508
308 1.7118

Originally Posted by Cigar

I thought it was the other way round, i.e. lengths were different to prevent chambering larger calibres in small chambers. I much rather fire a 243 round in a 308 rifle than vice-versa!

Your never going to fire a size up in the wrong chamber anyway due to the diameter

Originally Posted by Cigar

I thought it was the other way round, i.e. lengths were different to prevent chambering larger calibres in small chambers. I much rather fire a 243 round in a 308 rifle than vice-versa!

For some cartridges this is true but not the .308 family. There is enough difference to prevent , say a .260 chambering in a .243. The trouble spot is between .270 and 7mm where the difference is only 0.007'. For this reason the .280 and the 7mmWSM have their shoulders moved forward to prevent chambering. A .270 or a .250 for that matter on the .308 case is unlikely for that reason. Firing a .243 in a .260 only results in embarresmemt and endless leg pulling by all that find out about it.
Regards Grandpamac.

Thanks for the great replies. Good to see the voice in my head speaks to others the same way!!

With regard to the resizing option, I’ve read that there is some advantage to passing the brass through a 7mm08 FL die first. Opinions??

Also, I’m not setup for neck turning. Is it worth it for this onetime exercise or will it be a process that I’ll utilise in future reloading endeavours??

I necked straight down from .308 no neck turn