Re: 7MM08 brass from Lapua 260
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: shoot4fun</div><div class="ubbcode-body">Why will Lapua 260 brass need neck turned? I know guys that made 260 Rem brass from Lapua 243 and had to turn to keep out the donut but it appears that the 260 to 7MM08 change is only about expanding the neck and all other dimensions are equal.
The R-P 260 brass I used for testing did not require it. It all came in just under trim length with no donuts after one firing.
My load is published data from the Hodgdon web site data center and test loads were fired at ambient temp of 92 degrees with high humidity. There are no pressure signs I could see.
I do realize that Lapua brass may give me slightly less case capacity and increase pressure some but I would compare capacity before loading.</div></div>
When you neck up, you turn shoulder material, which is thicker, into neck material. When you neck up you usually have to turn off the doughnut at the base of the neck.
<span style="color: #3333FF">Edit:
The cases of the .260/7mm-08 are no different. It's a question of how much, not if.</span>
Necking down makes the whole neck get thicker. You don't always have to turn down necks from a downsized case. If you have a tight neck in your chamber you need to.
<span style="color: #3333FF">EditII:
If at any point you have too tight of a neck in your chamber you will get a pressure spike. As you noted the 47.2 gr. of H4350 is max. All it takes is a little pressure spike over that to loosen up primer pockets. Check your necks and your loose primer pockets may go away.
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-good luck.
