I bought some new10mm Starline nickel plated brass from Midway about 6 months ago. Last week I shot 100 rounds. The cases were not significantly bulged and the primers didn't look deformed, so I don't think I was over pressure. I also weighed each charge individually. When depriming and sizing, I noticed one case had a tear down the side. I have seen this before with 38/257 and 9mm brass that has been shot many times, but never with new brass. I figure it might be from a flaw in the material.
(http://pic20.picturetrail.com/VOL1362/13695381/24585439/410046762.jpg)
There are also numerous scrapes or lines around the base (circles in red). They go around the entire base. If there was only one or two scrapes I would figure it was the extractor, but this was new brass fired once. I am wondering what could make this scrape marks, and if it could weaken the case if done near the mouth. The scrapes are deep and show the brass color under the nickel plating. I can think of a few possibilities: Magazine feed lips; Uplula loader; sharp edge on slide; ejector; and extractor. I am not sure how the ejector could do it all the way around, but I put it down anyways.
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My glock had some rough edges on the extractor that would rough up the brass pretty good when i got it, i took it apart and filed the edges then polished it. Much better now.
So this case is a once fired case. You noticed nothing out of the ordinary when you fired the round, only after you recovered the brass and attempted to proceed with reloading?
Did you see any other cases like this?
Do you have any unfired brass left from the same lot?
Examine that and see if there are any deformities.
Make up a dummy round or very carefully load one of you other brand new brass rounds into a magazine with a sharpy mark on the top. Feed and eject that round and see if the marks are made after cycling. If so get some cheater classes and look at the slide, chamber, magazine... what ever would be in that quadrant on the case.
If it was just one case I would guess a bad apple got through maybe.
Quote from: The Earl o Sammich on September 17 2014 03:19:39 PM MDT
So this case is a once fired case. You noticed nothing out of the ordinary when you fired the round, only after you recovered the brass and attempted to proceed with reloading?
Yes it is 1x fired. I noticed it while sizing. It went through the sizing die too easy.
Did you see any other cases like this?
No, not split cases, but all of them had scrapes around the base .
Do you have any unfired brass left from the same lot?
Not any that aren't loaded. I have some unfired loaded ammo that has the same brass
Examine that and see if there are any deformities.
Make up a dummy round or very carefully load one of you other brand new brass rounds into a magazine with a sharpy mark on the top. Feed and eject that round and see if the marks are made after cycling. If so get some cheater classes and look at the slide, chamber, magazine... what ever would be in that quadrant on the case.
I will try that
If it was just one case I would guess a bad apple got through maybe.
Do you have any other brass you have fired from that gun that you have not processed?
Maybe check it and see if you have any of the scraping.
Also, You mention that you found it after it went into the sizing die...just to rule it out, check your sizing die and see if it has any grit or shavings in it and clean it real well.
Auto's bang up brass pretty good on they way into and out of the chamber. Hand cycling doesn't simulate this very well.
Split case on one loading is most likely either a bad charge or a bad case.
I had the same thing happen using factory loads of pro grade ammo, sent the 50rnds of spent cases that ruptured 9 of them along with 50 unshot rounds back to prograde . They recalled all 10mm loads p, it's been 2 months & still nothing. At least there was no damage to my G20, I guess even starline has bad brass??
If you have a good micrometer, measure the case head. I would be curios to know.
Some brass can be brittle, at certain stages in the stamping production the brass undergoes annealing to keep it softer and more malleable. That particular piece may not have been annealed properly leaving it brittle from the stamping process.
Yes, it is possible that something caused the annealing flames to flicker as that brass passed through...something could have blocked the heat of the flame from heating it evenly. The brass is suppose to be rotating in the flame for an even heating.
Think about a large operation and many thousands of brass being made, did it miss the annealing process. ::)
Also that is a nickel electroplated brass, that too can change the malleability of the brass...
Split brass happen, I have found many first time fired brass split, some guns, like the HK-MP-5 10mm have fluted chambers and are really tough on brass.
Is it anything to worry about? ??? Short answer is No! If you have a bunch that are splitting it my be a quality control issue.
Now here is something else to think about. Nickel is fairly hard and can scratch steel dies, it ruined my steel 357mag sizer many years ago. Solution - New carbide sizer dies... :D
Quote from: sqlbullet on September 19 2014 07:50:51 AM MDT
If you have a good micrometer, measure the case head. I would be curios to know.
Too late. I already pushed it all the way through a sizing die to get rid of the bulge. It was the first piece I used in case it didn't work I wouldn't damage my other brass.
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