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kdvarmint
04-26-2013, 02:11 PM
Can someone tell me what this is. If I'm right, I got problems. Have 11 loads thru this brass. Just noticed these "rings" close to the base on several cases. 308 win. lapua brass.

Al Nyhus
04-26-2013, 04:10 PM
How much are you setting the shoulder back when you resize? -Al

kansasvet
04-26-2013, 04:10 PM
Looks like you are very close to case head seperation.
Put one in the shellholder in your press, push the top of the case to one side with your finger, if what I suspect is right it shoud snap off at the line in the photo rather easily.

kdvarmint
04-26-2013, 04:54 PM
Looks like you are very close to case head seperation.
Put one in the shellholder in your press, push the top of the case to one side with your finger, if what I suspect is right it shoud snap off at the line in the photo rather easily.

d@#^! I was afraid of that. Snap! Started using a new lot of powder, thought pressures seemed higher. Might have caught it sooner if I was the one shooting. Back to load development.

Thanks.

John Kielly
04-26-2013, 05:18 PM
Load variations might accelerate the issue, but I, like Al Nyhus suggests, would be looking at how far the shoulder is being bumped back during case prep. It only needs to be sized/bumped j-u-s-t enough for the case to chamber with no, or barely any felt resistance as the bolt closes. It's damn hard to get case separation when the brass is snug in the chamber.

XBBR Shooter
04-26-2013, 06:01 PM
These rings and the separations that will follow, are the result of headspace, not high pressure.

Seek the crush - negative headspace is your friend.

Al Nyhus
04-26-2013, 06:50 PM
kdvarmint:

Again, I ask the question: "How far are you pushing the shoulders back during resizing?"

If your answer is "I don't know." and/or "I don't have the tools to check it.", that's fine. :cool: We can go from there.

Good shootin'. -Al

kdvarmint
04-26-2013, 07:08 PM
kdvarmint:

Again, I ask the question: "How far are you pushing the shoulders back during resizing?"

If your answer is "I don't know." and/or "I don't have the tools to check it.", that's fine. :cool: We can go from there.

Good shootin'. -Al

I don't have a bushing to check the 308. I was starting to get "snug" bolt closing last year while only neck sizing. Bought a body die and adjusted it to where the bolt just closed easily. I thought my pressures were a little high last year but never had any issues. The primers on these cases are definitely flatter than on the ones from loads I had left over from last year. I can also see some marking from the ejecter pin hole in the bolt face on the brass case. Same load I've been shooting for the past two years. The only immediate change is lot of powder.

Thanks.

John Kielly
04-26-2013, 08:25 PM
.... but, if you have the case floating in the chamber, the primer will fire & back out of the case to the depth of the free space, then when the powder ignites, the case will belt back & cause the primer to flatten sort of like a mushroom & you end up with something like excessive pressure signs. In those circumstances, there's no reasons why an ejector rod wouldn't show some degree of mark on the base of the case. Every time it does that, you'll get case stretch in front of the head equivalent to the free chamber length. Maybe the new powder has an influence, but if you got varying degrees of the same signs with your old powder lot when you changed was your case prep, I know which horse I would be backing.

Been there, done that, got 200 useless primed cases to prove it.

kdvarmint
04-26-2013, 09:10 PM
if you got varying degrees of the same signs with your old powder lot when you changed was your case prep

Not sure I comprehend that statement.

I haven't changed case prep for 300 rounds before this. What you say about the head space makes sense. Could be coincidence the brass got stressed to the failure point at the powder lot change. I have never seen this before, and thought separation is what it was. Just wanted to get input from those with more experience. I do appreciate the opinions and thoughts.

Al Nyhus
04-26-2013, 09:25 PM
Get yourself one of these Hornady Headspace guage kits and then you'll know where you're at.

Fired case:
http://img.photobucket.com/albums/v467/tenxal/anneal13162.jpg (http://smg.photobucket.com/user/tenxal/media/anneal13162.jpg.html)

Same case checked after being sized. You can see that the shoulder has been moved back a bit less than .002:
http://img.photobucket.com/albums/v467/tenxal/anneal53161.jpg (http://smg.photobucket.com/user/tenxal/media/anneal53161.jpg.html)

Make sure and remove the primers before checking, as they will skew the measurement .002-.003. You can buy the body (red piece) seperately and the individual inserts (silver piece) or the body and complete set of inserts for small money.

Lastly, don't rely on 'feel' alone. If the die and the chamber aren't matched well, you can be setting the shoulder back a l-o-n-g way (.007-.009) before bolt closure 'feels' okay...due to the die not sizing the diameter of the shoulder enough.

Hope this helps. -Al

kdvarmint
04-26-2013, 10:07 PM
Got it. I'm curious now to see how far I'm off. Thanks for the advise.

alinwa
04-27-2013, 12:18 AM
kdvarmint, please listen carefully to the advice you've been given and allow me to stress one point if I may...... this is not a pressure issue! This issue will not be addressed by backing the load down. I'm NOT saying you shouldn't back the load down, I'm just saying that the ring is a definite, irrefutable sign of something else..... excess headspace. IMO this is excess headspace caused by over-sizing. Al Nyhus is really tracking like a boss here, PLEASE take the time to understand what he (and the others) are saying :)

And thank you for your last post. I believe you WILL find it, and if you've the time, take a hacksaw and split the bottom of a case. Take a chunk out of the side and look to SEE the inside of that shiney, grainy ring.

You've come to the right place for advice. THANK YOU for listening to it. :)

al

kdvarmint
04-27-2013, 05:27 AM
alinwa, I feel confident you guys are hitting the nail on the head. It makes logical sense. A head space gauge kit is in order before I go further.
Again, thanks.
kd.

Larry Elliott
04-28-2013, 11:47 PM
The advice given for adjusting FL and body dies by their makers to screw the die tight down onto the shell holder is mostly wrong and will lead to excessively short cases and excessively short case life. One reason that neck sizing was such a great idea back before we had all the nifty measuring equipment available now was that cases didn't get their shoulders pushed back. I've seen FL sized rimmed rifle cases fail on the second firing in ex-military rifles with "generous" chambers. Placing a sized unfired round next to a case with only a partial separation showed that the shoulders had been moved back about 1/8" or more on sizing. An absolute guarantee to give head separations.

With a properly adjusted FL or body die your cases will fail from expanded primer pockets before you have a head separation. Also, if you don't have one of the Hornady/Stoney Point headspace tools, and are adjusting the die by the feel of the bolt closing, the bolt has to be stripped first (spring loaded ejector removed along with the firing pin and spring). The bolt should close with some feel on a properly sized case, something you'd never notice without a stripped bolt. By the time the bolt closes easily, you've got the case WAY too short for a long and happy life.

Dick Grosbier
04-29-2013, 08:24 AM
If I'm right, I got problems. Have 11 loads thru this brass. Just noticed these "rings" close to the base

Well you are right you "got problems" those are cases that are very near ready to separate. You are pushing the shoulder back too far, this causes the cases to stretch each time you fire and the head will separate shortly. It has been my experience you cannot push shoulder back much more than 1 or maybe 1.5 thousandths without problems.
Been there , done that, in the middle of a match even, and I was winning at time. Case head came out in bolt but had to remove barrel to get main portion of case out.
Dick

kdvarmint
05-04-2013, 09:48 PM
Well I got the Hornady Head Space Guage Kit and did some measuring and sizing. Turns out I was bumping the shoulder back .008. Adjusted the die till the bolt closed smoothly. Bumping .002 now. The gun is a factory varmint for any who wondered. Got 12 loads out of the old brass. Have 1 lot of 50 with only a few loads through em and got 100 more new cases. One more important lesson learned. Thanks all for the help.

kd.

alinwa
05-05-2013, 02:29 AM
nicely done
:)
al