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Cases Separating after firing.

H

hypno02

Not Politically Correct
Banned !
Minuteman
Jul 23, 2006
1,426
469
South Dakota
#1
Hey guys. My losok 700 with an ER shaw barrel is giving me separated cases after shooting.

They're breaking off where they always do, about 1/3" from the rim of the case.

I'm shooting 178 amax's in front of 44.5gr r-15 through this .308. I've had 2 separate so far and most of the others have severe cracks. (near separations)

I'm using winchester brass, FL sizing, and this hasn't been more than it's 10th loading.

To me this looks like a scenario requiring new brass, your input?

Thanks,
Dom
 
#3
Re: Cases Separating after firing.

With 10 loadings I'd retire the brass, especially with ANY case head separations in the current lot of brass. You might try adjusting your sizing die on the new lot of brass, so that you are only bumping the shoulder back a couple thousandths on each firing. If the brass exhibits a shiny ring just ahead of the web, that's a sign of incipient case head seperation. Hope this helps.
 
#5
Re: Cases Separating after firing.

Headspace it is definitely right to be checked. If you're FL sizing everytime and you have a max headspace condition you're working the brass a LOT.

I don't know the numbers offhand for a 308, but the headspace variance that's allowed in a 30-06 is 14 thou of axial tolerance. That's a ton of work on the brass.
 
#6
Re: Cases Separating after firing.

So in other words, if I'm FL sizing, and the headspace is 'bigger', and I get a new lot of brass, maybe I should try strictly neck sizing next go around? Fire forming?
 
#7
Re: Cases Separating after firing.

If your chamber dimension are near the large size (diameters)and then your full length sizing them back down the brass has to go somewhere. It will grow in length that gets trimmed off. The brass gets thinner right in front of the solid head, eventually fails. Have had a few rifles where neck sizing was the only alternative...
 
#9
Re: Cases Separating after firing.


potential causes:

1. overworking the brass. do you know the proper way to set up a resizing die?

2.ignition erosion. Take a paper clip,etc. and bend it into the shape of an allen wrench. Hold the long end and use the other end to feel for a groove in the cases down in front of the web. But surely it would take more than 10 firings....

3. and yeah- headspace on the rifle...
 
#10
Re: Cases Separating after firing.

what's a losok 700? If the barrel is Shaw's I would think it would be a standard chamber or smaller. Who built the rifle? Did they check the headspace when they installed the barrel? How long are the fired cases? I know that's not a measure of the headspace but he may not have the tools to set up the FL sizing die. If the case length is 2.15 then we know one thing for certain....
JH
 
#11
Re: Cases Separating after firing.

It was built by Mark Lammers of LOSOK custom arms.

This rifle has 3k+ rounds through it so I don't believe headspace is an issue, as it was just recently checked.

What would be a better alternative guys:

1. Adjusting the FL die
or
2. Just neck sizing, using the FL die

Thanks for all the help so far
 
#12
Re: Cases Separating after firing.

I'd adjust the FL die and only use it when the cases begin to show significant resistance to chambering after neck sizing and loading. That may take 3 or 4 reloadings when neck sizing only. Get a Lee Collet Neck sizing die...polish the mandrel a bit, and you'll get much more life. My experience. About every 6 or so FL sizing, you should consider annealing the neck and shoulder. I have a .243 that, if you FL size (with a neck bushing) and just bump the shoulder back .001 or .002 will stretch cases so you have to trim every other firing and will separate cases after 6 loadings. Using the Lee Collet sizer the cases just don't grow in length after 5 or 6 reloadings.
 
#13
Re: Cases Separating after firing.

"I'm using winchester brass, FL sizing, and this hasn't been more than it's 10th loading. To me this looks like a scenario requiring new brass, your input?"

Rifle headspace is irrelivant to a hand loader who knows what he's doing. Setting the shoulders back too far will always result in eventual head seperations.

You have been lucky so far, don't push it. Head sepertations are potentially serious, toss all the cases in that lot, they are spent. You have been lucky so far, don't push it.
 
#14
Re: Cases Separating after firing.

"I'm using winchester brass, FL sizing, and this hasn't been more than it's 10th loading. To me this looks like a scenario requiring new brass, your input?"

Rifle headspace is irrelivant to a hand loader who knows what he's doing. Setting the shoulders back too far will always result in eventual head seperations.

Ten cycles isn't doing too bad but you have been lucky so far, don't push it. Head sepertations are potentially serious, toss all the cases in that lot, they are spent. You have been lucky so far, don't push it.
 
#15
Re: Cases Separating after firing.

If your chamber is generous and you FL resize, you are pulling the brass away from the case head each cycle. If you can use the brass for this rifle only, neck size, collet is fine, but you will need new brass. One bright spot is that collet sizing should improve your group size.
 
#17
Re: Cases Separating after firing.

I noticed when I began lubricating the brass when I am FLSing that it helps lower the stress on the brass.
Imperial sizing wax and Necos Moly on the neck did the job for me.
What FLS die are you using?
 
#18
Re: Cases Separating after firing.

I use a Forster "bump" die on 308. It is set up for just a slight amount of shoulder set back. I use it until the brass causes the bolt to "click" (not open smoothly), then I FL size with a FL die that is adjusted to size only slightly more than the Forster bump die.
 
#20
Re: Cases Separating after firing.

Best way to regulate shoulder bump is with a set of competition shell holders. It can also be done with shims, but you'll find out that as the brass work hardenes the amount of "bump" will change. It's easier to corret using the shellholders.

You'll also need a tool to measure shoulder length.
 
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