I was FL resizing .338-06 cases and noticed that some of them didn't have any resistance when I drew them down and out of the die. Other cases had the normal resistance I am used to feeling when resizing cases - resistance at the top, and resistance as the case neck is drawn down and onto the neck expander. The loose cases didn't have ANY resistance when they came back down and onto the neck expander.

All of the cases are Winchester and recently tumbled. I do not lube the inside of the case necks when I resize. These cases have all been fired out of the same rifle since new, and none of them have ever been trimmed. I normally do not keep track of how many times a case has been loaded and fired, so some cases in this batch have been fired more than others.

I started to separate the "loose" cases, and when I was done, I measured their case lengths. Here's how they came out:
Loose cases: 2.480 - 2.488"
"Normal" cases: 2.475 - 2.480"

I also measured some known once-fired cases and new brass (resized to .338-06, but not fired). Here's how they compare:
Once-fired cases: 2.470-2.472"
New cases: 2.472"


I would suspect that the "loose" cases have been reloaded and fired more times, since they are longer. Even the longest cases, however, are still below the maximum case length for the .338-06 (2.494"). Are the "loose" cases shot-out? If there is no resistance when the case is drawn over the neck expander, will there be enough neck tension to hold a bullet consistently? I am thinking of pitching the "loose" cases, since.30-06 brass is cheap to replace anyway. I have never seen this before, though, and I wanted to see if anyone else would care to comment.

Not sure about the length issues; but in terms of neck tension, I would seat a bullet in the cases where you don't feel the expander ball dragging on the up stroke - see if the bullets seat with some tension. After seating in the case, can you put the tip of the bullet against the edge of a wooden table and push the bullet in any deeper with just your thumbs? This is kind of a field test for adequate neck tension. And once the bullet is seated, what is the difference in outside neck diameter between the cases that had resistance on the expander ball and those that didn't?

I took some outside neck diameter measurements....

New unfired cases: Before seating a bullet, .359-.360". After seating a bullet, .364".
Tight cases: before, .360-.361". After, .365".
Loose cases: before, .360". After, .363".


It would seem that the necks are a little thinner in the "loose" cases.

Roskoe, could his headspace be just a touch long, giving Dan too much flow into the neck? Thus thinning it out? Normally my necks get thicker, not thinner. I also think Dan should trim.

I use a Redding die to bump down the neck. Then I use a Sinclair mandrel to size the inside diameter,in my opinion this gives excellent inside neck diameter, and consistent neck tension. Tom.

Dan In Alaska:

I think your "loose" cases are your old old ones. It may be a good idea to keep track of how many times your cases are fired. Good luck.

If they are getting loose, its more than likely from work hardening of the brass. Try annealing the necks.

BINGO!!!!

I've seen this many times before includeing with the .338-06. I don't like annealing case necks so those thathave loosetension go to the scrap pile.... (soon they will crack)

I ALWAYS keeps my lots of brass seperate and shoot them as groups keeping track of how many times they have been fired ect....

DM

A bit of headspace could certainly accelerate neck thickening. I kinda got the impression that the trend was going the other way, though. Actually, you will get into less trouble with necks a little on the thin side than those a little too thick. You haven't also had issues with cracked necks on this lot of brass as well?

This is what I am thinking. The loose ones have been fired more times. I used to keep track of how many times each case was fired. I did it for years, but never ran into any issues, so I stopped doing it. I thought I was being too anal. I guess I will go back to being anal with my next batch of brass.

After all this, I am VERY curious as to how many times these "loose" cases have been fired and reloaded. I may start an experiment with a batch of 10 new cases. Each time I head to the range, I will fire them and keep them separate. I wonder how long they will last?



Nope. No cracked necks, or ANY cracks for that matter.



Another interesting realization is that none of these cases have ever been trimmed. The "loose" ones seem to be wearing out before they get long enough to require trimming. I like this, as trimming cases is one of my least favorite things to do.