30 BR neck turning problem

[dunraven]

am prepping 6BR Lapua brass to be used in a 30BR rifle. have noticed small cracks or splits in maybe 90% of the cases, running parallel to the long axis, at the neck/shoulder junction, about 2-3 mm long. They seem to be internal, at least not noticeable until the necks are turned.

Am I stressing the metal by expanding cases from .243 directly to .308?,using a sinclair expander mandrel) I find it hard to believe that all these cases are 'defective'. And, can they still be used?

 

[Preacher]

Seems as thats a lot of stretching all at once.
Try to take em up,not down) in steps of no more than .020 at a time and see if that helps....

 

[AlNyhus]

The latest 6BR Lapua cases are not annealed nearly as much as the older ones were. I used to anneal as a final step before fireforming, but now find I need to anneal as a first step before necking up. I first noticed this with some lots in early 2008 and this cooresponded with the flash holes not being as consistent as in the past.

Still the same great cases..just need a bit more tweaking, is all.

Hope this helps. -Al

 

[AlNyhus]

Try to take em down in steps of no more than .020 at a time and see if that helps....

He's necking up, not down.

 

[expiper]

I blow my 30x47 cases out with the shotgun powder method....and have no case neck problems...they seem better than if I mechanically expand them in one or several steps....I have not made any 30 BR's this way and am only thinking out loud ...how abut you Al Nyhouse...I know you do a boat load of em...and can get em to work pretty well!! grin....Roger

 

[dantiff2]

dunraven-- I also had those split marks on the necks of my Lapua 6br brass ! Some were deep enough to worry me but they fireformed right out. A friend of mine had a couple and he had some split necks, two or three out of one hundred. I'd neck up slowly, maybe in steps.. And a good lube..
Dan

 

[AlNyhus]

Hi Roger. I've blown 'em out using pistol powder packed down with tissue paper and topped by a wax wad. Honestly, I just don't feel I get as nice a result this way. The other thing that bugs me about this method is that the external donut you form when you expand up over a mandrel is now on the inside when you fire 'em that way....so that still needs to be addressed.

After carefully measuring 100's of cases with pin guages graduated in .0002 increments, it's clear that the neck i.d.'s are anything but perfect whether you expand up over a mandrel or blow 'em out. So, I've changed the way I do my 30BR cases over the last couple of seasons to get around this.

Lots of ways to skin a cat, though. The 'early' Lapua 6BR cases were a bit more forgiving that the latest lots, though...you could get away with quite a bit more and they would still fireform nicely.

The 6.5X47 Lapua cases seem to be annealed more like how the earlier 6BR cases were. They sure make a nice .30, don't they?

Good shootin'. -Al

 

[expiper]

Good morning Al...yes the 6.5 cases are like the old time BR's....I dont mind the "step" on the inside because I have gone to "no turn" on just about everything....I must be gettin lazy in my 'old days' ....and with the lil bullts,110-125) and zero to .030" FB they dont "shank" far enuff in the neck to touch it anyhooo....
Hope ur warm and dri ...I cant wait till good weather...I have the groundhogs so "nervous" down this way that none will come out to check for a shadow!!!!ahhaha....Roger