Question about dinged brass

Decker9

Decker9

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I had a rifle built and have been trying to get it to do its thing. A few accuracy/inconsistency issues Iv been trying to sort through one by one kinda. I don’t believe this would be my problem, but thought I’d ask and see what others thought.

I’m using new 7 saum ADG brass, my first firings marked my brass the same as the photos here. My second firings, I trimmed to 2.025” (my Nosler book recommends 2.035”) and still got the marks.

Should I be trimming my cases back another .005”-.010” maybe? It’s a newly cut chamber on a new barrel. The marks are quite consistent, as in look the same after each firing.

I appreciate any insight you fellas may have.

 
My guess would be that this damage is occurring upon extraction/ejection, and not during the firing of
the round in the chamber. I have seen this type of damage when the ejector plunger spring is too strong.
Of course, if you have a CRF action, this would not likely be the problem. Dave.
 
My thought would echo Eagleye - is not likely something when firing - appears that a portion of the case mouth being rubbed or struck by something on the trip out of the rifle? Not certain that I can pin it down to more than that - so I have no suggestion for solution ...
 
Thanks guys, this action does have a wicked eject compared to what I’m use to. I will take note and see if I can notice anything next time I’m out here.

Cheers :)
 
May or may not be related to your issue, and might be just my imagination from that picture - but is your case mouths rather severely "rolled over" or perhaps excessive "de-burred" - looking at my reloads - after trimming, case mouth is typically square, full thickness of neck - then I chamfer inside attempting to get perhaps 1/3 or less neck wall thickness removed at the chamfer tool angle - outer edge gets lightest touch to remove burrs. Maybe I do it incorrectly - maybe fooling myself what I think I see in your picture.

My thinking would be that a "knife edged" case mouth would show more deformity, after an errant contact with something, then perhaps on a more blunt or thicker case mouth edge??
 
Here is how you can verify if the damage is during extraction/ejection or not.

As you begin to open the action, and as soon as you can see the fired case,
put pressure on the side of the empty case, holding against ejector pressure
until the bolt is fully back. Then slowly release the case and remove it from
the bolt face. If it now has no marks, you know it is damaged during extraction/
ejection and not during firing. Dave.
 
I agree with eagleeye. Strong ejector spring is making case mouth hit action on the way out.

If you want the ejection, remove the spring and clip a coil with a side cutter.

On my single shot rifle I have removed the ejector spring and plunger. Easier to just take the empty from the rifle.
 
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