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Old March 30, 2009, 10:38 PM   #1
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Mini-14 dented cases, need help!


Well I just took out my brand new mini-14 to the range and have good news and bad news. The good news is that after sighting-in the buckmaster 4x40 fixed power (got it for $99 at Natchezz close-out, what a deal) I shot two consecutive 1.75 inch 3 shot groups. I know, this is not tackdriver groups, but for a mini-14 with UMC ammo, I was very happy. I am sure with some hand loads, I can get that to 1.5 inches. Anyway, the bad news. The very last round of the 20-round mag got pinched as the bolt cycled with the bullet facing the throat and the primer end of the shell sticking out. (see photo of cartridge with dent) Also, as I was picking up the brass, I noticed that about half of them were dented-in at the mouth (also see photo). Anybody know what is causing the dents and the misfeed? Can the brass be reloaded? Thanks in advance for any info.

Last edited by PTS1; March 30, 2009 at 10:45 PM.
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Old March 31, 2009, 12:48 AM   #2
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The dents are from violent ejections. The misfeed can only be addressed with the rifle in hand.

The deformed case mouths are reloadable still. They may suffer a slight loss of case life, but will still work just fine. The reloader just needs to be careful while sizing. If the expander hangs up on those case mouths; it can damage some dies, and will ruin the case.
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Old March 31, 2009, 10:28 AM   #3
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Sometimes I will stick a needle nose pliers inside the case mouth and gently OPEN it so that the jaws spread apart and round out the case mouth somewhat.

I don't try to repair the dent, I just want to make the dent in the mouth less dented so there is less chance of the sizing die hanging up.
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Old March 31, 2009, 11:14 AM   #4
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The dents occur because the ejector starts the case spining when the mouth clears the receivers, and the spinning brass hit something before it clears the gun. You can usually find where it hits the gun from the brass marks left behind. If you can afford the spare part, you can play with cutting turns off the ejector spring to reduce the force of the spin. There will come a point, if you weaken it too much, that it has trouble kicking the case out at all, so I would save this fiddling until you have your hand load established. You may end up tuning that spring to just the one load and accepting dents on some others. I would not try to affect the spin by messing with the extractor claw plunger spring as you may disable extraction unexpectedly.

As to the cases, rather than needle nose pliers, get round nose pliers. They won't put a crease anywhere in the case mouth. Sinclair makes a die body for their expanding and outside neck turning mandrels that can be used to straighten the inside of a case mouth. To avoid shortening case life, you probably will have to anneal these case necks every third loading or so until you get the dent cause addressed.

As to the feed, it can happen if the magazine is not all the way up. Check the magazine catch holds it where it should? Also, try just not filling the magazine. Load it two rounds short of its capacity. Some magazine springs jam up too hard for best function when full.
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Old March 31, 2009, 01:39 PM   #5
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You can buy aftermarket gas tubes to reduce this or get an adjustable gas regulator. The little gas tubes come in different inside diameters and change how much gas is released to operate the system.
I believe Brownell's sell them in a set of different diameters.
The adjustable gas block is more expensive but really neat. You can actually shut it off for single shot operation or go full open to shoot any type of ammo or any setting in between to reduce the force of ejection.
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Old March 31, 2009, 01:56 PM   #6
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Old March 31, 2009, 02:24 PM   #7
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Old April 1, 2009, 04:31 PM   #8
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use a bullet

I foolishly sold my Mini-14 a few years ago. Mine dated back to 1988 or so. It was one of the first in SS.

anyway, even then the cases would get mangled that way.

I just assumed it was the nature of the beast, and didn't tamper with the gun.

If the cases weren't squashed bad, I'd CAREFULLY re-size them, sometimes smearing a bit of lube in the case mouth and slowly pressing it into the die.

For the bad ones, I had an old piece of 2 x 4 about 6 inches long. I had drilled a hole in a little smaller than a 7mm bullet and pressed a jacketed 7mm into it noe up. I'd gently press the open case mouth down on this to flare out the squashed part. ( I suppose 5mm would work just as well). and then finish the re-sizing.

BTW, I do agree with frankenmauser that you need to insepct the cases as this does shorten their life IMHO
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