Lapua Brass Cases - for .260 Remington - or - 7mm-08 Remington Application
Wanting to use Lapua cases in either a .260 Remington - or - 7mm-08 Remington application.
From your experience, would it be best to neck up .243 Winchester Lapua brass cases - or - neck down .308 Winchester Lapua brass cases ?
From your experience, what process and tools are required for each ?
A trip through a FL size die should convert the 308 to either with no problem. You may want to size in a 308 die first. Check the neck thickness and trim length afterward.
Blowing out from .243 using shotgun powder will result in the longest and most uniform necks, as well as the thinner than from .308 brass. If you have a custom chamber this could work.... it's also a pita.
Necking up using a mandrel will result in the most non-uniform and thinnest necks.
Necking down from .308 using a die(s) will give thickest neck brass. Necks will form crooked using a single pass through a 260/7-08 die but will be adequate for any factory app. Necking down using a stepped neck bushing will yield straight necks but is quite expensive. Necking down from 308 will generally result in a donut.
All are "doable" but I'd probably choose to neck down the .308 brass if it's a factory rifle. I suggest you get your new die and just cram the cases thru it, one pass and you're shooting. 99% of the world will be made happy by this procedure.
I've tried it both ways and prefer using .243 brass. (assuming there is no possiblity of a .260 round being loaded in a .243) If you've a factory rifle probably either way would work but my first go at this sort of thing was with a custom barreled rifle in 7-08and .308 brass had to be neck turned while .243 didn't.
I was able to load full power loads from the get go with the resized brass and I guess I'm in the 99% because I found the accuracy to be more than very good.
I know you asked about Lapua, but Norma makes 7-08 brass. I don't use it because I'm not wealthy enough.
Nosler makes .260 Rem brass as well.
I am in process of buying a Browning A-Bolt titanium offered in 7mm-08. Plans are to shoot "as is" for the time being, but possibly custom rebarrel to .260 Remington or .260 Remington AI in the future. Weird huh ?
Years ago I bought a set of Redding forming dies for reforming 30 caliber mag cases to 7mm Remington mag and they worked pretty slick.
I have not checked yet, but there most likely is a forming die set for application of .308 Winchester to either a .260 Remington - or - 7mm-08 Remington offered by Redding.
Although others have suggested just using a full length die, my past experience forming magnum cases has not produced satisfactory results, but most likely was something I was - or - was not doing during forming process.
I would cull out a handful of 308 cases with high thickness variance, and neck turn trial & error for settings that produce a good thickness after downsizing. If you turn up onto the neck shoulder a bit & with downsizing, there won't be any doughnut. You can also leave your false shoulder for fireforming headspace. I would improve a 260, as there is plenty that can be in stock form.
I suppose now you have your pick of small or large primer in 308 brass. But I'd stay with large for this capacity..
I load 243 and 260 for my granddaughter. The 260 came first and I prefered to neck up 243 brass to 260. 308 was a little shorter than 260 min trim length and it made the neck pretty thick. She now has a 243 also, so I no longer resize either. I keep all brass sized to the headstamp to minimize the chance of her shooting a 243 bullet in her 260 or try and load a 260 in her 243.