I noticed that out of 250 pieces of 6.5x47 brass about 10 look like the pic below, which look to be case head separation issue. Only time I've ever had case head separation was with a 1xLC brass shot out of an AR-14 where the case actually separated. Primer pockets have always went out 1st before there was a case head issue I guess for 308/260.6.5CM and 223. With the 6.5x47 the primer pockets just do not get loose. I've stop counting how many firings I had on these cases but it has to be over 25 so I'm not complaining and i will be retiring all 250. Shoulders have been bumped 0.002 every other firing and the cases have been SB annealed few times. On 9 of the cases you can barely feel anything with fingernail but one almost feels like it has been cut with a saw from the outside lol. I shined some light in the case and filled it with water and it does not look like case head has been actually separated. Just looks weird form the outside. This is probably a dumb question but doesn't the case head separate from the inside? How can the outside of the case look like pic 2 and 3 but not be separated?
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Case Head separation Question
- Thread starter LA260
- Start date
I had something similar on a set of brass. The only way to truly tell is cut one, cross section. See how much of the web is left. Mine actually turned out to be fine and the line was from some other repetitive force on the case.
25 firings, you've got your money's worth
25 firings, you've got your money's worth
No, not exactly.
Think of it as a piece of clay being held by your two hands and being slowly pulled apart. The middle get thinner and thinner until it so thin it breaks apart. This is kinda what's happening to the brass, however, the pressure from firing pushes material to the outside surface against the chamber. So as the brass case is being pulled apart, where the thin part is observable in on the inside. rather than the outside.
This is why it's a good idea to inspect the inside of brass with some kind of feeler tool. I use a large paperclip that I've straightened out and put a little 90° bend on the tip and run in over the inside to feel for any depression forming in that area above the case head. This way I can detect a problem before any visible cracks or that telltale separation line you see on the outside of your cases.
As the brass is pulling apart, it's not pulling apart uniformly. So, around the diameter where it's coming apart there are places where is completely separated (and often will allow gases to come through), but stays together in sections of that diameter to keep in from being a complete separation. Take one of those and fire it again and it WILL totally separate.
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I retired a batch of cases with a bunch of firings recently
About a third got culled because of loose primer pockets but then I got a separation and retired them all.
Cut a case and see what you have.
I’ll put up with a lots but separations are a pain in the ass.
About a third got culled because of loose primer pockets but then I got a separation and retired them all.
Cut a case and see what you have.
I’ll put up with a lots but separations are a pain in the ass.
The only two ways I know of to check the condition is, like what was said earlier, use a feeler tool for the inside, or what I have done, is take one of the worse looking ones and cut in half vertically to be able to see a good cross section of the case web at the bottom.
Honestly, it's more than likely just time to pitch them. Case separation is a huge pain and can be dangerous in certain cases. Not worth all the effort and chance to squeeze one or two.more rotations out.
Honestly, it's more than likely just time to pitch them. Case separation is a huge pain and can be dangerous in certain cases. Not worth all the effort and chance to squeeze one or two.more rotations out.
You can use a bore scope to see inside. I have a hawk eye borescope and you can see the crack. I'm going through the same thing on my Dasher brass (Lapua). It has 15-16 firings and everyone said that's about all you can expect. I have the same line on the outside and I cull those when I see them. Primer pockets are fine. I final order new brass this week and will trash all the old stuff.
Here's some pics you might find of interest:
This first one is a case I found laying around for a long time where it's separating and you can see where some gasses have leaked (I guess just kept this as a reminder) and the one I cut out doesn't have any separration, but is just to show my little paperclip tool and how it relates.
The next two pics are the inside of that same case as the one at the top of the previous picture.
Thanks everyone for your thoughts. I went ahead and cut the worst baffected brass see what the inside looks like and it's not pretty. On a positive note there is no donut that I can't see so at least I don't have to worry about that.
And a random retired Hornady 6.5CM case that's been fired 8 times from a AR 10 with 38.3 Varget and 123gr AMAX/eld and has been resized 0.003 every single time.shows no signs of case head seperation. Weird.
And a random retired Hornady 6.5CM case that's been fired 8 times from a AR 10 with 38.3 Varget and 123gr AMAX/eld and has been resized 0.003 every single time.shows no signs of case head seperation. Weird.
Out of curiosity what is the initial case growth with new brass in that rifle?
After that many firings that brass owes you nothing.
After that many firings that brass owes you nothing.
Agreed about the brass. No complains.
Virgin Lapua measured 1.464. after 1st firing it was 1.469 and it settled at 1.4715 after 2nd or 3rd firing
That’s why I asked.
I’m guessing first firings stretched the cases a bit and created. a bit of a weak spot and repeated loads wit a reasonable bump very slowly worked on that stretch point.
OP, if your initial growth was..002ish like I set my chambers your brass might have surpassed my last lot of 260 cases.
You could jam the first firing or do a false shoulder and get the brass to fail at the primer pockets first possibly.
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I bump it back to 1.469-1.470. I just got another barrel from a different Smith and the dimensions are pretty similar if not bigger. Haven't shot it yet but a 1.469 resized case from the old barrel Chambers without any issues in the new barrel so at a minimum the virgin case will grow 0.005
I’d really consider a hard jam or false shoulder if it’s much over .005 If you want maximum case life.
