Case Head Maqrks

[DustyRusty]

I have a group of LC67 MATCH cases that all have a mark on the case head. I'm aware of extractor and ejector marks but not sure of this one. Any opinions are appreciated. I'm thinking it will work fine but not sure.

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[CINDERS]

Could the bolt group from a Garand do that when striping it from the mag.
The dent wont matter to much, just ensure the bottom edge of the rim is not impinged into the extractor groove and the radius of the rim is not bulged outwards, a small flat diamond file smooth them out if any and it'll be fine.

[oldfoneguy]

Exactly what CINDERS said. Make sure they're flat on the bottom so your bolt will close completely and there's no external bulge on the rim which can affect your extractor. Looks like an angry Garand got to them. That's excellent brass I have 500 rounds of it. Wears like iron, I have loaded it half a dozen times to M2 or M72 spec and it shows no signs of stress. Shoot it and enjoy.

[browningautorifle]

Agreed, looks like it's striking the op rod outside when departing. The mark under the rim is extractor. I don't think any will affect operation even as they are. I've run worse.

[Bruce_in_Oz]

Fired from a serviceable M1?

"Mil-spec" load?

Fed from the clip?

That last one can be important. If the cases are fed from the clip as the bolt closes, the "drag' slightly reduces the speed of forward bolt travel.

HOWEVER, if you are "single loading and inserting the round manually into the chamber, then releasing the op-rod / bolt, that assembly will be moving quite quickly when it contacts the case head and the extractor has to move laterally ans the ejector spring is being compressed. Old John Garand (and the boffins at Springfield) put a LOT of work into fine-tuning the M1 action.

Many years ago, when I was fooling around with these rifles on a regular basis, I understood that a PROPERLY set-up specimen would strip and accurately feed sized EMPTY cases from the clip and cleanly into the chamber. All those odd surfaces inside the rifle body acted on the SHOULDER of the case such that the cases (and bulleted rounds), were perfectly aligned with the chamber. MUCH slicker ad elegant than bashing the bullet over assorted lumps and bumps. If a rifle would not do this, one or more components needed replacement.

I know lots of folk are obliged to do this on some ranges and some think it mangles the ammo less than mag feed.

If the case is of correct dimensions, but with a nicely annealed (softish) shoulder, the ramming action of the extractor and ejector of the fast-moving bolt, can shove the round hard against the chamber shoulder and push the case shoulder BACKWARDS a little. This essentially INCREASES headspace by a couple of 'thou'. That sort of thing may alter primer ignition and put unnecessary additional stress on the rear of the case.

"Single-feeding" a Swedish AG-42B the same way REALLY mangles the rims of the fired brass. Single-fed from the magazine, (with the cartridge actually retained by the mag feed lips), prevents this problem.

Just my two South Pacific Shekel's worth.

[Daan Kemp]

My immediate reaction would be ejector mark. That, of course, would depend in the gun it was fired in. Such a mark indicates quite violent ejection.

[DustyRusty]

Thank you all for sharing your tips.
When I test some loads this spring, I will watch each case for new marks.
This is new .308 ammo and was fired by me from an M1a.

I will examine the bolt for faults and chamber some clean dummy rounds from a full magazine. And check for possible case nicks from the op rod upon ejecting.

Your extractor tips made me think of what a extractor might do to the case head if it couldn't snap up and over into the extractor groove easily.

[browningautorifle]

was fired by me from an M1a

Exact same marks as an M1 rifle. Still no worries for you.

[DustyRusty]

Yup. Same bolt almost as the M1.
Maybe a Shuster adjustable gas plug would be a fun experiment.
On the M1a I can turn off the gas port just to see if the brass is marked by my easy manual oprod movement.

[browningautorifle]

a Shuster adjustable gas plug

I used one and yes it will turn down the pressure. You have to use the same ammo always or re do the gas setting. The M1A turned off will be a bit hard to eject, you have to break the seal. Yes the marks will be gone.