Dear Ganderite - I’m scratching my head.

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Dear Ganderite - I’m scratching my head.

Hello Sir. I love your informative posts and look forward to reading all the time. You should have your own column on here. I’d like your input on something that happened and I can’t get my head around it.

Worked up several loads for a 6mm AI. Known and safe charges. Powder, brass, primer and bullet lots are consistent. Kept detailed notes through everything. Fired two rounds a couple days ago and measured them up just because. It’s what I do. Base to datum measured 0.004” longer than all other cases I’ve measured up until now. Normal measurement is 1.7705” and I’ve been bumping to 1.7685” +\-. I’ve FL resized these cases and measured them up. All dimensions are within previously established tolerances. They are stiff as you know what to chamber. Checked them against other sized brass. Same dies. Same lube. Same shell holder. Trim length is fine. Still have 0.005” before I would need to trim.

How is this even possible? I’m at a loss. Can’t find anything dimensionally wrong with this brass and it just doesn’t want to chamber easily. Like I say, I’d love some insight.

Thanks for your time.

Joe



I have no idea.

Brass needs annealing?

Oil in chamber or lube on case?

But I bet a Gun Nut will chime in here with a good explanation...
 
swollen at the web after pushing the shoulder back, needs small base dies in order to size the body of the case down enough to fit into the chamber
 
I'm not clear if they are now reloaded and difficult to chamber or empty after sizing.

Brass flowing and the neck becoming too thick after several loading and trimming cycles? Should be able to measure the diameter of the neck when loaded and compare to others that chamber okay. Coating with sharpie would show this too.
 
What point using for a datum point ...? the mouth of the case or the shoulder

Loaded round or empty brass ... trying to chamber ?

Is press over caming?

if pres is overcaming , and a empty case. I would find a pop can and cut a little circle the size of the case rim and re size the brass with the little circle in the shell holder with the case on top

If that works .. find a file and trim the top of the shell holder
 
Well I was the fellow who messaged Ganderite originally and figured I’d report back with what was discovered. I took a couple things for granted when I started loading for this cartridge. In answering a couple queries from responses previous, head to datum measurement were all head to shoulder. These were fired cases and empty while discovering the issue. By detailed record keeping, I have been measuring case necks, head to shoulder, web diameter, just below the shoulder, overall length. And here’s where my error manifested itself.

I had started with used brass. Got it for nothing and had no idea how many firings were on it already. I had no new brass to compare to. Recorded my measurements and continued to do so throughout my loading and firing cycles. I’m on my 10th loading of these cases. I went and purchased some new cases for comparison and my used cases that I started with all measured 0.004” larger than a new case at the web. The problem cases are showing 0.0045” larger than starting diameter so I was walking the line with chambering/no chambering the whole time. I tried seating primers in the problem cases and the pockets are loose as a two dollar you know what. So head expansion is my culprit.

I’ll be pulling the bullets in the loaded rounds and starting my load work up in this rifle all over again as my baseline for monitoring the cases was flawed from the get go. Silly error I know but I’d rather err on the side of caution. This particular charge is obviously to hot regardless of new or old cases I’d surmise. This brass owes me nothing so its no biggie to junk it.

As a side question, could this brass have been work hardened before I ever touched it and wasn’t springing back a bit like it should? Or with these loads being on the toastier side of things, it flashed hard and hot enough that it “instantly” work hardened sort of scenario? This is the first time I’ve experienced something of this nature so I’d like to learn from it if I could as well as save my face from damages.

Thank you for the responses as well guys. And my name is Curtis but thank you Ganderite for respecting a persons privacy.
 
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10 plus loading with a hot load. and the primer pockets are opening up

The Brass does not owe you anything

I have heard of 20 plus on a mild rifle load, and where the person stopped keeping count
 
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