https://forum.accurateshooter.com/threads/strange-dent-in-fired-case.4016999/
Slow powder, non- mag primers, low neck tension, add to soot problems.
Black soot on cases head scratcher for me???
- Thread starter hweissert
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Slow powder, non- mag primers, low neck tension, add to soot problems.
Bob Wright
Well-Known Member
If your chamber is inspected by the Smith, then the above is where I would go.
Also for the guys who bushing neck size, my Redding die only necks about 80% and the area at the neck/shoulder junction is larger by some factor. My premise is, quicker sealing near the neck shoulder is one positive piece in many factors. Mandrel sizers work great too, so it leaves the other problems in the discussion
However you go about it, the neck must slam open into the chamber, primer must be igniting a larger portion of the powder, neck tension must resist the forward movement against primer detonation, resulting in the brass to seal in the chamber neck.
FWIW, I only get soot to the area on the neck where the bushing die stops sizing, at that 80% line. I only have .004 neck clearance for a clean bullet release.
Annealing certainly does complete the fire forming process, especially on the belted mags with .020 shoulder space on first firing. In your case, if headspace is not consistent after firing, that is also a problem, as you are setting your dies to a moving target. All fired cases at the shoulder datum line should be within .0005- not more than .001.
Well got it figured out. Turns out he'd gotten a new reamer that he just had in reserve for when the current one was worn out. The packages got mixed up when he chambered it and it was cut with the new reamer. Beings he thought was old one, it wasn't mic'd to check for spec prior to chambering. When he pulled it out of the Trey and realized it was actually cut on the new, he checked both. Old reamer and normal speck is .317 on the neck. New reamer wasn't finish ground at the manufacturer and was left at .3235. Therefore, the next was 5.5 thousandths larger than spec. Good news is I'm getting a new barrel on them and didn't have a disaster in the process of shooting it. Bad news is now I gotta wait for barrel to get here. Thanks for all the comments and replies.
Bob Wright
Well-Known Member
Holy moley!
Old aerospace saying from machinist to engineer:
"It's not exactly like the print, but I think you'll like it!"
Old aerospace saying from machinist to engineer:
"It's not exactly like the print, but I think you'll like it!"
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Or, "Measure it with a mic, mark it with chalk, and cut it with an axe". Lol
I thought I'd of caught that in the brass. But, I guess it never could blow the neck out enough to get a odd reading. I guess when I went up on powder, and have zero other pressure signs and even 2gr over max, it was just sealing off the shoulder to stop the blow back and not ever expanding the neck enough for me to get an abnormal reading on mic or caliper
longestrange
Well-Known Member
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Can you tell us who made the reamer?
I didn't ask that. But will see if I can find out. I did personally see the measurements from the mic and caliper so know it is indeed 5.5 thousandths bigger
Rflshootr
Well-Known Member
I have a wild guess, but I'll keep that to myself until we hear back.
capona
Well-Known Member
Everyone's looking to the right, and that train came out of nowhere on the left.
For sure!!!
Thanks for the link. In my case I think I have it all covered. RL16, CCI 450, .002" under loaded size. FLS non bushing type. I ordered a .2400" mandrel today to try 3 thou neck tension.
slikmrc
Well-Known Member
Good to hear what should have happened did due to the chamber issue. Kind of amazing the rifle shot as good as it did with the problem. Glad you found the problem, stinks your out a rifle for a while.
Hotolds442
Well-Known Member
That scrap barrel would make a nice candidate for a 28 Nosler build.....
