260 brass necked up for 7-08

Trm82

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Feb 24, 2014
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Location
Alberta ,Canada
Hey guys can I neck up 260 and use it for
7-08 ? I'm trying to help my brother-in-law out and load his 7-08 for him but because there's no large rifle primers anywhere and I'm not willing to share my stash I found some 260 srp Pettersen brass I thought we could go that route since I know where there is fed 205 m primers available.

I looked at the brass dimensions
and it looks like we should be able to but I thought I would check here just to confirm before he purchases
 
My recommendation would be to use a 270 mandrel, and then a 282 mandrel to bring the next size up
 
A friend took pictures of the ignition of primers, the type of flash, the length of the flash, etc. and the pictures were posted in Precision shooting magazine some years ago.

CCI 450s are the hottest, they also have thick cups which you will have to have. Tula Magnum primers may be hotter than the CCI 450's and have a very different flame type.

I have made 7/08's out of New 243 Winchester brass. The key is to put a very, very heavy chamfer on the inside of the neck, and I use Redding long tapered expander mandrels. Necking up in one step from 243 to 7/08 would be a disaster, and if you anneal first, the shoulder is apt to collapse.

I played with lubes, Lee Sizing wax in the toothpaste type of tube is much better than Imperial. Pro blend makes a Pre-assembly lube used for lubing ball bearing sets during assembly that is exceptional also.

Annealing after necking up may help in case of life if is an issue.

I would urge you to go any route and NOT use small primer brass if you hunt in the extremes of Cold, I have been down this route, hang fires are a real ****er.

Federal 205's M(Match) have the thinnest cups of any primer, perhaps a tie with Winchester, they also have the coolest flame, so they are a no go.

TRM82, factory ammo seems like your best option since there are no large rifle primers available to you with a federal 205 being a total Failure for two reasons.
 
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