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Discussion Starter #1
I have been going to some reduced match to get my feet and jumped on in yesterday. Other than M16 qualification I never shot over 300m. I shot it with my AR.

I shot 691 6x.

Standing 169
Siting rapid fire was 186 3x
Prone rapid fire was 189 3x
Prone slow fire was 147

I'm not one to make up excuses but I noticed that were a lot of other shooters that did so here is mine.
This is my first time shooting at 600 yards and I was doing OK. I had shot mostly 8s and 9s and a couple of 10s. Then a case broke off in the chainber. I thought that my day was over but my spotter grabbed a cleaning rod and help me get it cleared. I got back in to position but I went to sheet after that and shot 5s and 6s.

But the main thing is some of the most fun I've ever had with a rifle. I will be back next month.
 

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Case head separation can happen, usually with reloads. Limit your match ammo to second firing of the brass only. You also will need to check you brass when reloading. If this is new brass/ammo, you should have a look at your headspace as well. I don't see this as much with ARs but I guess it can happen. I see it more often w/ 7.62 brass.

Before your match and maybe between courses you may want to swab out the chamber with a dry mop just to ensure a clean chamber.

Bruce
 

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Yup saw that happen to guy this last Sat at a full XTC in Racine Wi. Same thing neck broke off in the chamber and he had to come off the line to reshoot his string. Didn't get how many reloads he had put through it but first time I have seen that with AR. I limit my reloads to 2 for match use then third is for practice or local comp , reduced course.
 

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Discussion Starter #7
Those are good numbers. What was your load?
My loads were all SMK
200 yds
69 gn
CCI 41
21.2 H335

300 yds
77 gn
WSR primers
23.5 H335

80 gn
WSR primers
23 N140
 

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case head separation

I first met case head separation about 20 years ago, when I bought a used FedOrd M14. It was built by a gunsmith student at the college. I learned to check my fired cases inside with a paper clip and to recognize incipient case head separation on the outside of the case by the thin, bright ring that appears about 3/8 inch from the base of the case. Some might call it a pressure ring.

It is likely attributable to a chamber that has max headspace AND resizing the cases too short, perhaps by screwing the sizer die all the way to the shell holder, as some manufacturers recommend.

This is where that case length gage comes in handy: compare the length of your fired cases to the length of your resized cases. During resizing, move the shoulder only several thousandths, just enough to permit the bolt to close on the empty case with only spring force.

Also, when adjusting the sizer die, mark the shoulder with a sharpie. When the shoulder of the die rubs the ink on the sloped shoulder of the case, then you are close. Check case lengths again in the gage and in the chamber.

Turning the sizer die 5 degrees changes the height by only .001". The length of the arc on the circumference of the die subtended by 5 degrees is only .038", slightly more than a thirty-second of an inch, almost a millimeter. Make delicate adjustments and recheck your settings. Wasting a few cases now will save many cases in the future.

Highpower rifle competition is a very challenging and rewarding pursuit. Good luck.
 

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Discussion Starter #9
Here's a pic of my failed case. About all the pics I've seen of case head separation right at the rim of the case. This one broke about 1/3 of the way down. It was the cases 3rd firing. Would y'all consider the case head separation? I didn't feel anything abnormal when fired and the round hit the 9 ring. I didn't notice it until I tried to load my next round.
 

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Classic case head separation. The fix is in the posts above.
I quit checking every case with a bent wire and only check the ones I can see a ring in after tumbling.
Some of those will make another cycle and with brass situation of late...
 

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case separation

USMC Armorer who built my M1A NM told me with virgin LC Match cases load them 6 times. With once fired LC Match cases load them 5 times. Then discard. I have never had a case separation while keeping this rule.
 
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