Necked down cases still getting dented shoulders w/ firing

[roob]

Guys,

I have some .308 brass necked down to 7mm-08. I did it, a few cases had crumpled shoulders but it wasn't a big deal, I put it down to the thick necks caused but the necking down or a bit too little lube or whatever. Shot them all and they were fine.

After shooting them I neck sized them and got a few crumples again. Again figured not a big deal as only shot once so won't have stretched heaps to thin out the necks yet.

I've done the second shoot and 3rd neck sizing with these now and still getting a couple of crumbles. It's never big, only ever the same small size but 3 times?

Should it be clear by now or have I weakened the shoulders or something?

Thanks.

[bunnybuster]

Could be accumulated lube inside the dies,give 'er a good cleanout with solvent before using next time but don't forget to lube the cases or

they WILL stick,bintheredonethat,

Be Safe BB

[tom604]

^^^^^^^^ what bunnybuster said, the little dent are caused by too much lube but if you use too little they stick. try using graphite powder in the neck as well

[yoshie]

Have you trimmed to length?

[roob]

Hi guys,

Lube on the inside of the neck is done with a nylon brush, just one push up and down.

Outside is done on the lube mats, rolled back and forth for the body and normally just finger contact with the necks. Maybe I didn't do enough on the neck itself.

[roob]

Have you trimmed to length?

Yep, trimmed after each shoot.

Though bugger all came off.

[Shotfox]

Sounds like to much lube.. What type of lube are you using ? The re-sizing die tollerances are very small and it does not take much lube to dent the neck. I would strip the die to check and see that nothing is obstructing the resizing process and the die is clean. But it sound like to much lube.

[Lorgar]

By necking the cases down you will have effectively thickened the necks which will be adding extra friction/pressure contributing to crumpling the shoulder.

When I swapped my .308 for a 7mm I also necked down all my brass, about 400 cases, and got 1 crumpled shoulder for maybe every 25 cases? I don't neck turn and they're only thinning through firing, stretching and trimming. Mine are now 2-3 times fired since and I only have a couple left that didn't resize properly on the last go.

Check your lube as suggested, but I'd also suggest the problem will improve itself with firing as the necks thin.

[Seconds]

If you're neck sizing only don't bother with rolling the cases on the lube mat for the body.

Just do the neck

[roob]

Sounds like to much lube.. What type of lube are you using ?

The regular RCBS one that comes in their kits.

[Shotfox]

Sounds like to much lube.. What type of lube are you using ?

The regular RCBS one that comes in their kits.

I see. What i use is "inox" spray non food grade. Firstly I spray a little on a microfibre cloth and wipe the cases lightly - that's it - works a treat, inexpensive and you can buy it anywhere, bunnings is the cheapest and can be used to clean your gun as well. What i found with roll on lube is that it tends to thicken over time and as it gets old resulting in the problem you have now.. Try a diffrent method and see how ya go i guess.

[roob]

Cool guys, thanks.

I have a few loaded with dented shoulders at the moment so will see how they go on the next trip and sizing.