necking up Lapua 6.5-284 to 7mm

[lrgoodger]

Now I remember why I have a fire-forming barrel for my 30BR. It was to eliminate case issues caused by necking up with a mandrel. Necking up 6.5-284 cases to 7mm is a lot less expansion than 6BR to 30BR, so I thought the problems might be less.

I just necked up three 6.5-284 cases to 7mm and there is a visible dishing of the shoulder where it was pushed downward by the pressure of pushing in the mandrel. I measured new cases at 2.163" length and the necked up cases at 2.156" length. Some of that difference is due to widening of the neck reducing its length, but some of it is also due to crushing the shoulder downward. I know it will be blown back out when they are fire-formed in the 284 Shehane chamber, but isn't this just as bad (or worse) as pulling an expander ball back through a neck? I worry that some of them will never straighten out properly no matter how many times they are fired, just as I have read about the expander ball issue. What do you guys think?

I'm leaning toward making a fire-forming barrel for this case too. has anyone done that for necking up 6.5-284 to 7mm?

 

[Quinc]

I just expanded 100 pieces of 6.5x284 to 7mm. Have you tried running it through a body resizing die after you necked them up?

 

[barnesuser28]

i necked up 100 pieces of Lapua 6.5x284 to 284 win and i didnt notice the issue you are having, i made sure to use PLENTY of imperial lube.

 

[Bobr]

400 pieces of Lapua 284-6.5 expanded with a K&M expander no issues. Each case was lubed inside with a Qtip and imp wax

 

[Whitehunter]

Neck up in two steps. Try necking up to .277 and then go up to .284 .

 

[Travelor]

Are you putting plenty of lube on the mandrel when sizing up?

 

[alf]

And a heavy chamfer on the inside of the neck?

 

[lrgoodger]

This batch of Lapua brass has the worst neck tips I have ever seen with regard to dings and nicks in the edge. Chamfering them before expanding is a good suggestion. I had thought of expanding in two steps but have not tried it yet. I'll do a couple more tonight and see if chamfering, plenty of lube and two step expanding make this issue go away.

Thanks guys.

 

[Steve Blair]

I expand in one step for Shehane cases using Ballistol lube and encounter no problems dishing shoulders. I'm on my second 1000 cases. My expander is a Sinclair but any other, like the 21st Century unit, will work as well or better.

 

[Ecomeat]

I have expanded 300 Lapua cases up to 7mm so far and only lost one..... to the collapsed shoulder that you have experienced
I do it in two steps, using a Sinclair 270 expander mandrel as first step, and then the K & M 7mm expander. Plenty of Imperial sizing wax on a Q tip, as many others mention.
The Sinclair 270 expander die, as a "first step", in a Forser Co ax press is so quick and easy to do, and nothing to lose, that it just made sense to try it. For me, the results make it worthwhile.