Necking down .308Win....or not?

roysclockgun · Dec 13, 2011

Hello Group,
I have been stumbling around, learning about hand loading since the 1960s, and somehow, I never ran into this problem.

In loading for my wife's 7mm-08 I full length resized some .308Win. to 7mm. The 7mm-08 fired brass had been reloadong fine, but when I tried to seat the 7mm bullets into the resized .308Win cases,I got a bulge in the neck, which was enough to cause the cartridges not to chamber. My bullets measured .284", or 7.21mm, so nothing wrong with the bullets.

I then miked the walls of the neck. Wow! The sized 7mm-08 brass miked .0013" to .0014". The necked down .308Win. measured .0018" to .0019". This would indicate the need for a neck turning tool and one more piece of work to do.

I considering just buying 100 new 7mm-08 cases and forget the trouble of necking down .308Win. Brass. Once we get the wife's rifle zeroed in, I doubt that she will fire more than 50 rds. per year. I would not need the neck turning tool for any other caliber that I am loading.

Funny thing is, I have necked down a lot of 30-06 cases to make .270Win. brass. I also neck 30-30 brass down to 6mm! Never had any trouble with rounds not chambering, and'or bulges in the neck.

Anything else that you can recommend would be appreciated.

TIA
Steven in DeLand, FL

Guest · Dec 14, 2011

Well, the easy thing to do would be to buy a bag of 100 7mm-08 cases and be done with it. But, it might be interesting to turn the necks on your 308 cases. I'd probably just go easy.

As to why it happened, I'd be curious to know what brand of 308 brass you were necking down and how the neck thickness compares to any -06 or 30-30 brass, as well as how the necked down .277 and .243 necks compared to this problem brass. It might just be a tight chamber.

Oldtrader3 · Dec 14, 2011

I think that your neck thickness issue is pretty common. You sized down .024 inches in diameter and that extra material has to go somewhere. I would have been surprised if the case necks had not required reaming or turning.

roysclockgun · Dec 14, 2011

The too thick neck walls occured on Win., R-P and FC brass.

New problem! I acted hastily because I wanted to get loading *fast*! "Act in haste, regret at your leisure!" I had never used Lee loading dies in the past and they were on a table at the local gunshow, in the 7mm-08 that I needed. The decapping pins appear to be not replaceable in the decapping shaft. Again, in haste, I grabbed a 7.62x51mm case that had a Berdan primer and quickly broke off the decapping pin. I have plenty of extra pins for my other brand dies. These Lee's shafts appear not have replaceable pins. Is this the case? Do I now need to buy the shaft, with decapping pin sweated in?
Best,
Steven

longwinters · Dec 14, 2011

I've resized Lapua 30-06 brass to 280 and never had any problems. No neck turning etc...ever. I have also resized 30-30 to 7-30 Waters...and no problems. The 30-30 brass will have a ring a little above the shoulder, but it shoots out on the 1st shot afterwards. I have necked down 308 Lapua to 7m-08 and while having no problems seating bullets, my Sako did not like any loads I tried....so I just buy 7m-08 brass for it.

Long