Old 6.5’08 handloads

[QStott]

Due to some life changes I recently moved all my reloading stuff and firearms to my fathers house. Today I was snooping around and found some 6.5’08 panther reloads from 2006.

Some background first. During that tIme, my best shooting buddy and I were heavily involved in high power long range matches. (600, 800, and 1000 yds). Both of us had Remington 700‘s chambered with the same reamer and they worked great with 142 smks.

This reamer had a snug neck and a long throat. It’s almost the same as a .260 Remington. I used Laupa .308 brass, necked it down and turned the necks. It was a winning load. I found 165 rounds I had loaded with N150 today and saw some corrosion around the neck of a few. The bullets were moly coated. Upon closer inspection I began to find split necks in about 1/3 of the loaded rounds. These had been fired three times and loaded the fourth time.

I called him to see if he had any old loads with a similar problem. He said the had found some .223 rounds loaded for service rifle matches in similar shape. He pulled them apart. The were loaded with a VV powder also, bit not N150. His cases were Winchester.

The cases have green corrosion , mostly at the shoulder and neck where the splits are. When he pulled his bullets (about 300 of them) he said the powder was “clumpy”. Mine were stored in plastic ammo boxes in an insulated shop, but not really climate controlled. It was just a few with corrosion, but several necks had split running down into the shoulder.

I’d like to know what caused it. They didn’t split when I loaded them. I had fired 35 rounds out of the batch and the fired cases looked fine.

Anyone run across anything like this? I’m wondering about all kinds of thing. Moly? Ammonia contamination? Moisture? Chemical reaction in the powder?b

Thanks!

 

[RegionRat]

MoS2 is susceptible to humidity in air and is a known Lewis Acid forming material when wet.
I don't believe it was your root cause, but in the presence of liquid water it may play a role.

Without typing out a complete list of all the things that can cause brass necks to corrode and crack in storage, the bottom line is going to end up being exposure to chemicals.

Anything like gun cleaners that contain ammonia for copper removal are a risk since they are typically found in your chamber or nearby your ammo or guns, and therefore is on the suspect list.

Anything used to clean up dies and was not completely removed, is suspect.

Anything like tumbler or brass cleaning additives or polishes might also contain chemicals similar to ammonia that open the door to the problem are on that suspect list.

When the cartridge brass is under stress, as in the elastic grip around the neck over the bullet, it becomes especially vulnerable compared to non-stressed brass when in the presence of alkali contamination.

The two cases in the photos may or may not be cracking and corroding due to a single cause.

There is also the possibility of external contamination after the fact.

The initial work hardening state is difficult to know, but since these are wildcats, the neck annealing state may have played a role as well. This does not explain the verdigris but higher energy states (hardened metal) tends to get attacked first.

Take a hard look at anything chemical in your processes, especially if you plan for long term storage. And don't forget to look at gun chambers, dies, gages, and tools, with the same critical eyes.

ETA: The clumpy powder is also a bad sign. That can happen all by itself, or may be due to contamination after the fact. If there is any leftover powder stored, it is time to check it. If there are more rounds, it may be time to disassemble some to make your decision about breaking them all down easier to swallow.

 

[QStott]

I plan to break them all down. I’m especially interested in the condition of the powder inside. These cases would have been tumbled in corn cob media. It is possible I used a small amount if Lyman’s case cleaner in the media. My process was to lube and size cases after tumbling, then wash them with dawn dish detergent and air dry. It’s been so long now I don’t remember for certain. At some point I started tumbling wet with steel pins, a touch of dawn detergent and a tiny amount of lemon shine. These cases may have been cleaned that way, but I don’t think so.

The rifle has only been cleaned with either Hoppe’s or Kroil. There has been less than 1000 rounds fired in the rifle and they have all been moly coated bullets. I have one ot two products on my cleaning bench with ammonia, but don’t think they would have been in contact. My cleaning - gunsmithing bench is separate from the reloading bench.

The chamber Is fairly tight with this reamer. So no excessive case resizing was used. However, I did form these cases from .308 cases. I’ve never felt comfortable using .308 headstamped brass in this caliber. I have two other .308 caliber rifles. I trust myself, but if my descendants might not know the difference if I was not around.

I will check my notes and see if they show any other hints. My gut feeling is a chemical reaction pertaining to either the moly or powder.

Thanks for the reply.

 

[RegionRat]

Sometimes, it was the forensic work of very good chemists to determine the cause.
Without those talented chemists and the sophistication of very good labs, we would never have been able to determine the root cause of incidents like yours. It may or may not be found and sometimes there was more than one thing going on in combination to get the reaction. Good Luck and play it safe.