5.56 Case Gauge Problem ?

rewster

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Occasionally I will get a Lake City 5.56 case, after full length sizing & trimming, where the head will not go all the way into the gauge. Left pic shows it sticking up and right pic shows "normal".

DSC_4832.jpgDSC_4833.jpg


All of the brass has been trimmed to 1.749 - 1.750. Is it a minor shoulder problem with not quite enough setback ? Why is it only 1 in 20 or 25 come out this way ?

I did take about 20 of the ones that stick out, loaded them and shot them out of my AR with no problems. Any help would be appreciated.
 
Feel around the edge of the rim, sometimes there can be a burr from the extractor (fired from an overgassed gun maybe?). If you find that, lightly hit it with a file and then see if it gauges correctly.
 
Feel around the edge of the rim, sometimes there can be a burr from the extractor (fired from an overgassed gun maybe?). If you find that, lightly hit it with a file and then see if it gauges correctly.

I tried that on a couple but there were no significant burrs. On one I used a file a lot and still made no progress in getting to drop any farther at all.
 
I have had some LC cases where the rim was a little larger than normal. When dropped in a case gauge the rim held the case up just like your photo.

Here's a thought. Gauge all of the unfired rounds I take to the range next trip to make sure the rims are OK. Send um down range and segregate them. Go through the normal case prep procedure and see if any have "over sized" rims then.
 
Is there gunk/tumblining media, etc inside the gauge? Sometimes this causes the rim to stick out like you show. If it does, I will wipe the inside of the gauge and try again.
 
Feel around the edge of the rim, sometimes there can be a burr from the extractor (fired from an overgassed gun maybe?). If you find that, lightly hit it with a file and then see if it gauges correctly.

This. I see it more with my Garand than with my AR, but I've seen it with both.

You can turn the brass around on a rimless cartridge like these, and lined up properly, it should fit into the case gauge (just the rim..). If the rim fits in this backwards fashion, then the problem isn't a burr on the rim. If the rim doesn't fit, then it's at least part of the problem.

You could also lightly smoke (or sharpie) the case and rim, then drop it into the case gauge. Maybe even tap it in a little but to see if it will go, or rotate it a little. Then bring it back out and see where the smoke or sharpie markings have been rubbed off to get some more clues. Or get the calipers out and measure the case at several points and compare against the spec.

In my limited experience, every time I've seen this it's been coupled with a mark from the extractor that, when filed down lightly, allows the case to slip easily into the gauge.

Good luck, and let us know what you find!
Greg
 
Is there gunk/tumblining media, etc inside the gauge? Sometimes this causes the rim to stick out like you show. If it does, I will wipe the inside of the gauge and try again.


No gunk in the gauge. Twenty cases will drop in and #21 sticks out !
 
This. I see it more with my Garand than with my AR, but I've seen it with both.

You can turn the brass around on a rimless cartridge like these, and lined up properly, it should fit into the case gauge (just the rim..). If the rim fits in this backwards fashion, then the problem isn't a burr on the rim. If the rim doesn't fit, then it's at least part of the problem.

You could also lightly smoke (or sharpie) the case and rim, then drop it into the case gauge. Maybe even tap it in a little but to see if it will go, or rotate it a little. Then bring it back out and see where the smoke or sharpie markings have been rubbed off to get some more clues. Or get the calipers out and measure the case at several points and compare against the spec.

In my limited experience, every time I've seen this it's been coupled with a mark from the extractor that, when filed down lightly, allows the case to slip easily into the gauge.

Good luck, and let us know what you find!
Greg

Correct on the Garand rounds. I became a little paranoid with the 5.56 and decided to gauge my 30-06 rounds. Out of about 200 only 2 would not gauge. The rim stuck out. I filed down the extractor marks and they fell right into the gauge.

I tried the sharpie on the rim and banged it into the gauge. The black mark came off almost evenly on the entire rim !
 
Stick the rim in the case gauge first. If it goes into the case gauge then something other than the rim is the cause.

Well, that eliminates the "shoulder" theory. They do not go in rim first.

Since I've already loaded and shot about 20 of them with no ill effects, does anyone see a problem with using them as they are ?

- - - Updated - - -

Awesome idea.

My FNC batters the crap out of the rims to the point where the cases won't gage.

Do you still reload them ?
 
I had a Lyman case gauge that would sometimes do the same thing with LC and PPU brass, one out of 20 or 30 would stick up like yours. I also have a Dillon gauge and the ones that would get stuck in the Lyman drop right in the Dillon.
 
I've been taking my time processing a bucket of PPU brass. I will occasionally run into a casing that won't fit into the shell holder on the trimmer or the shell holder on my Lee priming tool. The Lee shell holder is tighter than the trimmer which has a Hornady shell holder. I've amassed perhaps 2 dozen cases so far that don't fit at all. I ran a couple through a small base die with not much improvement. I've had a Lee Bulge Buster set on my shelf for a while and I have a 380 ACP Carbide Factory Crimp Die so I figured I'd try a couple of the PPU 5.56x45 brass through it. It didn't take much effort to run a shell through dry but I chose to lightly lube the rest with Lee's lube. The 223/5.56 brass shares a shell holder with 380 ACP so why not experiment? The cases that refused to be forced into either or both shell holders now fall in as easy as all the other brass did after bulge busting them. I don't know where the break even point of buying the Bulge Buster kit and a .380 Carbide Factory Crimp Die is worth it for the brass you'll save but if you already have both Lee tools it is a way to reclaim some brass from the scrap box. It seems the carbide die resizes the rim as well as so maybe it'll fix the issue the OP has experienced too.
 
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