found a hot one!

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found a hot one!

Postby plant_one » Sat Apr 09, 2016 2:55 pm

so the case feeder is all dialed in, all my dies are set - loaded a dumm 250 FTX up in an empty case, got the hornady taper crimp set for 0.475 to start off.



after setting everything up i went through and resized and punched all the primers out. came across one peice of brass that must have been a rather warm load. i couldnt raise the shellplate all the way up as it was hanging up on the lip of the sizing die.

you can see the ejecter hole, and the extractor rescess from the bolt face. i dont have the primer as i had already cleared them all out with the universal decapper before i decided to resize them and then tumble the primer pockets clean.
Image

the case is buldged to .519 just before the extractor groove on the rim. it almost looks like a belted magnum!
Image



oops - this little fella tipped over before getting into the shellplate and i was clearing a jam in the case feeder.
Image
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Re: found a hot one!

Postby Hoot » Sat Apr 09, 2016 5:01 pm

Good Lord! :o

I wonder if the owner who shot that particular round knows how close he came to a real disaster? There's a range report around here somewhere, where I aborted the test about a third of the way through because pressures were rising too quickly as I worked up the load ladder. Had to pull a lot of loads down and toss everything but the cases. Might have been my experiment with double stab crimping Barnes. One stab in the front and one in the rear driving band grooves. (Too much of a good thing) Anyway, I knew I was going up too fast but stayed the course as long as my courage held up. About the time I stopped, I had rounds that were backing out like that imprinted head, albeit not quite that bad, but darn close. I have never seen a case head so close to failure as that one though, even my aborted load run cases were still salvageable. I can't imagine the condition where a factory 450b load could spike it's pressure that high, aside from an obstructed barrel. Boy, if it could talk... :?

Was that case among the ones you got from MN?

Hoot
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Re: found a hot one!

Postby Hoot » Sat Apr 09, 2016 5:05 pm

In hind sight, it may have been a round that wasn't too hot, but which had lubricant in the chamber.

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Re: found a hot one!

Postby plant_one » Sat Apr 09, 2016 6:02 pm

thats entirely possible too, one of many scenerio's that can cause an over pressure situation.

this was out of the brass i posted pics in that fella's thread in the classifieds so i have no idea of its history. just what i found when getting some prep work done.
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Re: found a hot one!

Postby Hoot » Sat Apr 09, 2016 7:45 pm

Reading the tea leaves on that round. There's no distortion where the web and case wall meet, In semiautos, that's the first place pressure starts to show up. Either it was the first shot down a barrel and chamber that went to the range really lubed up and never cleaned beforehand, or and I have seen this happen; A round failed to extract for whatever reason and a well intentioned person tried to pound it out with a rod, without an assistant holding the charging handle unlocked and pulling backward at the same time. Don't Laugh! I've seen it done with my own eyes. :roll: Some folks do not understand how their actions work. They're not direct or delayed blowback. I'm leaning more toward the second explanation as there are no swipe marks either.

Thanks for an excellent example to ponder; of something one rarely gets the opportunity to observe. Save it for posterity.

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Re: found a hot one!

Postby plant_one » Sat Apr 09, 2016 7:58 pm

theres a fairly good gouge on the case rim from the extractor, like it was trying to pull or somehting.

you're right it does seem strange that theres no case head swipes.

Image


i just noticed these marks around the edge of the case too

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Re: found a hot one!

Postby Hoot » Sat Apr 09, 2016 8:03 pm

Look down inside and see if the inside of the head/web looks like its peened from a rod pounding it.

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Re: found a hot one!

Postby plant_one » Sat Apr 09, 2016 8:12 pm

i cant get a pic but there is a small ring down in there. looks like you might be on the mark with the driving it out with a rod thing.
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Re: found a hot one!

Postby Hoot » Sat Apr 09, 2016 9:11 pm

While it's hard to explain in words and I don't have an image of it, I made a gizmo for stuck rounds from a piece of rectangular brass bar stock. Started out something like 1/2x1/4x8 inches. I rounded one side and taper ground the other down to a flat nosed chisel. It fits between the leading edge of the bolt and the front of the ejection port. It allows me to gently pry the bolt until it's unlocked and it remains stuck in there while I tap the inside of the case with a 1/4" brass rod, long enough to reach in from the muzzle. Couple of taps and the half-round wedge usually falls out, requiring a re-position, or in many cases, that's enough to keep the bolt out of battery for a further tap or two with the rod. Most of the seizures I've encountered were the result of Case Head Growth that either happened after a stout load, but more often and before I began meticulously checking them, was rammed into position using a case that had already exceeded the CHG tolerance of my chamber before I ever loaded it up. I bin sort all my cases now with a micrometer, before storing them after cleaning. Anything more than .5015 goes into the recycle bucket. Fool me multiple times, shame on me. :roll: Depending upon how tough a reload life they had previously, excessive CHG usually coincides with around the 4th-5th reloading. If they are fortunate to always be loaded tame, say plinking ammo, they never get out of tolerance. Ditto on loose primer pockets. At least, That is speculative as I rarely reload cases past 5 times as by then, they have grown too short to be in spec. That is an unfortunate casualty of loading them too tame, believe it or not. So, it's hard to win at that game. Something's gonna give...
By the 4th-5th reloading, I feel that I've gotten my money out of them anyway and no hard feelings. I've had really stout loads go out of CHG tolerance in as little as two loadings. All in all, loose primer pockets are pretty rare, given the distance between the small rifle pocket and the rim. Wish I could say the same for my 6.5 Grendel brass. That got a lot better after switching from Hornady to Lapua brass. Same issue with my 7.62x40 cases. Too little meat between the pocket and the rim. Haven't found a solution for that yet. LC brass used to last the longest, like 3 reloads. Haven't used up all my stash yet, so hard to say whether FC which took the place of LC, will do as well. Got plenty of them also. Both of those cartridges beg for more uumph. The price is short primer pocket life. :|

Hoot

Getting hard waiting for good weather as opposed to tolerable weather, to get caught up on my range reports. Whatever MI gets, subtract 5-10 degrees over here in MN. But then, at least we get misery increasing SW-NW winds for our troubles. Nothing but prairie to our west. ;)
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and then there were twins

Postby plant_one » Sun Apr 10, 2016 3:49 pm

so while doing some further handling stuff today, i found another of these crazy cases. i've now individually inspected the whole lot of them to ensure that there are no more hiding in here.

the 2nd one made it through the sizing die, and the bulge is noticeably smaller

Image

ejector and extractor marks are nearly identical, but the 2nd case i have appears to show a bit of an ejector and extractor swipe to them. notice that the ejector recess mark isn't a full circle like the one on the left which was the original find.
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