This isn't necessarily a reloading question but I thought someone here might have advice. I reload .223 and .308 perfectly with cases undamaged. I am noticing about 30-50% of cases have shoulder dents after firing in an AR15 and an AR10. I suspected that the cases were being damaged by hitting the case deflecter upon ejection. Can anyone confirm this? Regardless, how do I fix this? I have adjustable gas blocks on both rifles. Should I adjust them to put less force on bolt resetting? Appreciate anyone's help!
Shoulder dents in AR15 and AR10 cases
- Thread starter rawhitney
- Start date
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Put some lipstick on the deflector, then fire a round. Look at the case and check for lipstick. Might want to do it more than once to be sure, since you mentioned it only happens 30-50% of the time.
If it is the deflector, there are rubber bumpers you can glue on to help protect the brass.
If it is the deflector, there are rubber bumpers you can glue on to help protect the brass.
Nez, does it happen because of a a buffer/buffer spring not a match for the system?
cohunt
Well-Known Member
Use the fuzzy side of self stick velcro-- you can get it in lots of colors to match your upper--- it's common, especially in ar10
Is this a really light load?
This was my thought as well.Was the brass cleaned for the photo? If fired brass has soot back to here (your photo) , slow burn rate powders & necks not sealing on firing, would be my guess.
Little to no neck tension plays a part also.
Is a suppressor being used?
I've seen Dents like that from too light of a charge or necks not sealing properly, and gases being pushed onto the shoulder.
victor3ranger
Well-Known Member
Hmmm sure looks like hydraulic dents from a sizing die with too much lube.
It's possible that the brass is striking the deflector on the way out and if that's the case I would lean towards it being over gassed, not really a big deal if it is.
It's possible that the brass is striking the deflector on the way out and if that's the case I would lean towards it being over gassed, not really a big deal if it is.
Zen Archery
Well-Known Member
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- Dec 27, 2012
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Normal. Go to Velcro note above!
Yep, either the necks are not sealing during firing, or you have lube left on the shoulder that is cooking off and causing the dents. If it were hitting the shell deflector, the dent would be horizontal, not vertical.
How many times have those been loaded and are you annealing between firings (or after every other firing)?
How many times have those been loaded and are you annealing between firings (or after every other firing)?
Stammster2
Well-Known Member
Those are hydraulic, not mechanical dents. Sizing die excess lube is my bet.
