brass mouth markings


October 1, 2012, 01:36 PM
Hi, folks. I am shooting a DPMS LR308b and have been shooting it for over a year. On my last trip to the range I shot some Winchester FMJ/147 grn and got some curious marks around my case mouths. They look like an imprint of lands and grooves. I know this is impossible, wondering if anybody here has ever witnessed anything similar, and what may be going on. By the way they shot to moa.

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October 1, 2012, 01:40 PM
Do you have any method of measuring a fired case for length?

MAX OAL of a .308 case is 2.015".

If they are longer then that, you could be getting into the rifling leade.

To check that you need a .308" bullet that hasn't been loaded or fired yet.
(Not the bullet in a loaded round)

It should slip inside the fired case mouth with no resistance if the case mouth is free to expand normally in the chamber.

It is also possible you just have a dirty chamber and hard carbon fouling is marking the cases.


October 1, 2012, 04:00 PM
i bet its the factory crimp looks like a castel

October 4, 2012, 09:32 AM
If you were getting land/groove imprints on your case mouths, you'd not be with us.

October 4, 2012, 10:31 AM
I assume you are talking about these :

If so, im betting Jeeptim is on the right track.

October 4, 2012, 02:02 PM
Some crimp dies use a collet, such that the die squeezes the collet onto the very end of the case neck.. This leaves a distinctive marking, as the collet fjingers press a dent in the neck, while at the gap inbetween the collet fingers there is no dent.

As noted, it looks like the ramparts on a castle tower.... or like a rook chess piece.

Most LFCDs for rifle calipers are collet dies.... and several commercial ammo manufacturers use a similar collet crimp process.

not to worry.... you should still be able to reload the brass.

October 4, 2012, 05:04 PM
Factory crimp. Not to worry. Some even serrate the inside of the mouth before crimping. Try cast in that rifle, it's a hoot and WAY less expensive.

October 9, 2012, 10:05 PM
Thanks guys, your advise has eased my mind. They shoot great and they reload just fine also. I think the factory crimp is the issue, as well as a dirty chamber. Thanks again

October 9, 2012, 10:08 PM
Popper, how do you load lead and not have a cycling problem. What with the reduced speeds.

October 9, 2012, 10:19 PM
Does it look like this (

December 11, 2012, 01:00 PM
Finally bought some more of this ammo. Yes "Walkalong" they look just like that.
If I had looked at the last batch closer I would have known it is a factory crimp and there is nothing to worry about. This stuff shoots real well as least from my rig.
Thanks guys

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