Wondering when to retire .30-06 brass (sectioned brass photos included)

[243winxb]

Reading can be better at times. Some info on the internet may not be correct. No ones perfect.

 

[Ohio06]

Excellent photos. Thank you. I really appreciate you taking the time to share this--it's very helpful for me. I've been reloading for a few years, and I read a lot, but everything I'm doing is self-taught.

The marks I'm getting are similar to to the ones you showed on the right-most photo. I have seen a faint full circle of the extractor profile very rarely, but the more common marking is a faint half-moon shape.

Here's some of my own personal .308 brass that I tossed. Once they went through the vibratory bowl it was pretty easy to spot the bad ones. I tossed the entire batch of 300 pieces. They had around 11 loadings on them.

 

[1Moose]

Here's some of my own personal .308 brass that I tossed. Once they went through the vibratory bowl it was pretty easy to spot the bad ones. I tossed the entire batch of 300 pieces. They had around 11 loadings on them.

Does the 2nd photo (image of exterior of case) show a case that had ruptured, or is that what severe thinning looks like pre-rupture? Can you share if you saw any signs before your last firing? Thank you for sharing your photos.

 

[Ohio06]

Does the 2nd photo (image of exterior of case) show a case that had ruptured, or is that what severe thinning looks like pre-rupture? Can you share if you saw any signs before your last firing? Thank you for sharing your photos.

That was a case that had been fired. It exhibited a slight black ring where the thinning was upon ejecting the shell. The shell itself did not separate, as it still had a web of expanded material holding on to either side.

Prior to this I had seen no signs of thinning or rupture. With as little as I bump my shoulders I was surprised that I had this much thinning. This was the first instance of separation I had ever seen in any of my rifles. Typically I will crack the necks before anything.

 

[bigedp51]

Your shoulder bump is the equivalent of your head clearance when the cartridge is chambered. And the head clearance is the distance the rear of the case stretches to meet the bolt face. The thumb rule of .001 to .002 shoulder bump is well within the elastic limits of the brass and not have any stretching and thinning of the brass.

The .308 cases below were fired in a brand new Savage bolt action and the full length die was setup to make hard contact with the shell holder. The rifles headspace was not given nor the amount of shoulder bump. Meaning the actual shoulder bump and head clearance was unknown, so the case life listed is ball park. And if the shoulder bump had been held to .001 to .002 these cases would have lasted longer.

As you can see above the quality, hardness and thickness of the case in its base has a lot to do with case life. Example military .308/7.62 cases are made of harder brass and are thicker in the base and will last longer than thinner commercial brands of brass.

Bottom line, the cases in your photo look good, and I have cases over 25 years old that I lost count of how many times they have been fired. These were never annealed and fail with cracked necks with no sign of case head separations.

I use a $100.00 bent paper clip below, a RCBS Case mastering gauge that will show case thinning in .001 of an inch. This gauge is the Swiss Army Knife of gauges and also checks runout, neck thickness and other functions. In the photo below is a sectioned factory loaded Winchester .303 British case that stretched and thinned .009 on its first firing. And the rifles headspace was set below the NO-GO gauge, but the thin Winchester case had thin rims that added to its head clearance.

Your resizing die should be setup to bump the case shoulder .001 to .002 below the red dotted line below. And the closer the shoulder is bumped to the green dotted line the more the case will stretch and thin.

 

[1Moose]

Your shoulder bump is the equivalent of your head clearance when the cartridge is chambered. And the head clearance is the distance the rear of the case stretches to meet the bolt face. The thumb rule of .001 to .002 shoulder bump is well within the elastic limits of the brass and not have any stretching and thinning of the brass.

The .308 cases below were fired in a brand new Savage bolt action and the full length die was setup to make hard contact with the shell holder. The rifles headspace was not given nor the amount of shoulder bump. Meaning the actual shoulder bump and head clearance was unknown, so the case life listed is ball park. And if the shoulder bump had been held to .001 to .002 these cases would have lasted longer.

As you can see above the quality, hardness and thickness of the case in its base has a lot to do with case life. Example military .308/7.62 cases are made of harder brass and are thicker in the base and will last longer than thinner commercial brands of brass.

Bottom line, the cases in your photo look good, and I have cases over 25 years old that I lost count of how many times they have been fired. These were never annealed and fail with cracked necks with no sign of case head separations.

I use a $100.00 bent paper clip below, a RCBS Case mastering gauge that will show case thinning in .001 of an inch. This gauge is the Swiss Army Knife of gauges and also checks runout, neck thickness and other functions. In the photo below is a sectioned factory loaded Winchester .303 British case that stretched and thinned .009 on its first firing. And the rifles headspace was set below the NO-GO gauge, but the thin Winchester case had thin rims that added to its head clearance.

Your resizing die should be setup to bump the case shoulder .001 to .002 below the red dotted line below. And the closer the shoulder is bumped to the green dotted line the more the case will stretch and thin.

Excellent photos and images. With the new headspace gauges (just received), I'll be able to ensure I'm not setting the shoulders back any more than .002. This weekend, with a newly purchased headspace gauge, I was a bit surprised by how little die rotation in the press created a pretty large bump. <DELETED A BIT OF CONFUSING CONTENT I ORIGINALLY HAD HERE FOR FUTURE CLARITY.> I'll measure some previously loaded cartridges tonight to see how over-bumped I've been sizing the cases. Thank you.

 

[bigedp51]

Excellent photos and images. With the new headspace gauges (just received), I'll be able to ensure I'm not setting the shoulders back any more than .002. This weekend, with a newly purchased headspace gauge, I was a bit surprised by how little die rotation in the press created a pretty large bump. I suspect that I over adjusted a bit with the "sharpee-covered-bullet" technique. I'll measure some previously loaded cartridges tonight to see how over-bumped I've been sizing the cases. Thank you.

A picture is worth a thousands words and saves my two dyslexic typing fingers from becoming exhausted.

 

[1Moose]

Thanks to all of you who shared your insights, experience, and images. In case you're interested, I just measured how much I had been bumping the shoulders on my cases, and despite my best estimations/efforts I was bumping fired cases from 2.047 inches (with my gauge) to on average 2.043 inches (an occasional case measuring 2.0425). Aided by the recently-purchased headspace gauge, I had reset my sizing die to bump back to 2.045 inches (with a rare case showing 2.0445).

Early in my reloading with these cases, I know I was bumping shoulders farther than 0.004 as I simply followed the die instructions and they would rattle around in the case gauge. With my new routine, I hope to get more life and better performance.

Tip for others still learning about reloading (like me): For anyone looking to measure shoulder bump, be sure to de-prime your cases first, or simply seat the fired primer deep enough that they don't interfere with your "before" measurements. I know it's easy to troubleshoot this, but I'm offering it just in case it helps someone else save a few minutes time. It made me do a couple minutes of head-scratching.

 

[dougduey]

338 belted. View attachment 88471 The outside of the case should have a shiny thin line starting around almost all of the case. Here is a 223 separation starting in the body of the case. View attachment 88472

243winxb
Am I getting the beginning of case separation in the photos below?? It's 1x fired Nosler brass in my 338 Lapua. The second photo is Nosler brass 3x fired in my 7 STW. If so, I assume I should throw those cases away.

 

[1Moose]

dougduey, Others know far more about this than me, so I'll let them weigh in on what the images show or don't show.

Something that might be helpful. While I sectioned some cases (shown in original photos of post) with a die grinder, others generously shared the good advice to bend a paper clip and run it up the inside of the case. If you feel it catch in a particular spot on the case, that's a sign of thinning. I hadn't used that technique before, but I intend to in the future. And I'll cut one open if I ever get that catch from the paperclip to see how pronounced the thinning became.

When I first started using my Sinclair concentricity gauge, I had a "What the heck is that line!" reaction. I wondered how I had missed the tell-tale sign of case thinning until so late in my case prep (the very last step, even!). It turned out that the ball-style support platform that you rotate the case on was putting an absolutely perfect cosmetic line around the case (in two places, granted). If you're using that gauge, it could be worth confirming that's not part of what you're seeing in addition to giving the paper clip method a try. If you do and can report back, that'd be awesome.

 

[Buck Buster]

Your shoulder bump is the equivalent of your head clearance when the cartridge is chambered. And the head clearance is the distance the rear of the case stretches to meet the bolt face. The thumb rule of .001 to .002 shoulder bump is well within the elastic limits of the brass and not have any stretching and thinning of the brass.

The .308 cases below were fired in a brand new Savage bolt action and the full length die was setup to make hard contact with the shell holder. The rifles headspace was not given nor the amount of shoulder bump. Meaning the actual shoulder bump and head clearance was unknown, so the case life listed is ball park. And if the shoulder bump had been held to .001 to .002 these cases would have lasted longer.

As you can see above the quality, hardness and thickness of the case in its base has a lot to do with case life. Example military .308/7.62 cases are made of harder brass and are thicker in the base and will last longer than thinner commercial brands of brass.

Bottom line, the cases in your photo look good, and I have cases over 25 years old that I lost count of how many times they have been fired. These were never annealed and fail with cracked necks with no sign of case head separations.

I use a $100.00 bent paper clip below, a RCBS Case mastering gauge that will show case thinning in .001 of an inch. This gauge is the Swiss Army Knife of gauges and also checks runout, neck thickness and other functions. In the photo below is a sectioned factory loaded Winchester .303 British case that stretched and thinned .009 on its first firing. And the rifles headspace was set below the NO-GO gauge, but the thin Winchester case had thin rims that added to its head clearance.

Your resizing die should be setup to bump the case shoulder .001 to .002 below the red dotted line below. And the closer the shoulder is bumped to the green dotted line the more the case will stretch and thin.

Only thing I have ever noticed was a split neck now and then. Most of my brass was military 30-06 brass. Had to take the primer crimp off with a pocket reamer, some of them cases are well over 50 years old. I helped my father when I was 10 or 11 knock the primers out with a hand punch. I remember my father breaking the primer punch in the resizing die at least twice. He bought a punch that was made to be used by hand to pound them out. I am going to be 66 next month, they will last me the rest of my life and probably will last a long time into my sons life. They are only used for hunting rounds. But I believe some of them have had to been loaded 20 times or more. Good luck hunting and be safe.

 

[243winxb]

Am I getting the beginning of case separation in the photos below

Both look like normal die marks.

Belted magnums- seen a 7mm Rem mag that was neck sized only, till a fl sizing was needed to close the bolt.

When the head clearance/cartridge headspace is set by the shoulder, the case body in front of the belt becomes unsupported, in the chamber on firing. So i feel its best to fl size every loading. Bumping the shoulder back about .005" Many fl dies will do this using a single stage press, with the shell holder making contact with the bottom of the fl die. Not so on some progressive units.

Just my opinion. Others may be different. http://www.larrywillis.com see collet die. I never needed one for 7 & 300 mags.

 

[dougduey]

Both look like normal die marks.

Belted magnums- seen a 7mm Rem mag that was neck sized only, till a fl sizing was needed to close the bolt. View attachment 88703

When the head clearance/cartridge headspace is set by the shoulder, the case body in front of the belt becomes unsupported, in the chamber on firing. So i feel its best to fl size every loading. Bumping the shoulder back about .005" Many fl dies will do this using a single stage press, with the shell holder making contact with the bottom of the fl die. Not so on some progressive units.

Just my opinion. Others may be different. http://www.larrywillis.com see collet die. I never needed one for 7 & 300 mags.

Thanks for the info. I thought it was a normal die mark, but I wanted to make sure. I've never had case separation and don't ever want to. Usually the primer pockets are loose and the brass discarded before I even get split necks.