Burn on case

[Roger_Roger]

What causes the burn back on the shell cases?

[skeeterboud]

one cause I know of--- low powder charge which does not fully swell case to fill chamber upon firing .. so, gun powder leaks out into chamber, etc.... if you are reloading, I'd say you were far from max loads

[Mike D]

Typically not fully sealing in the chamber.

If on a semi auto like an AR the bolt may be unlocking an opening too soon.


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[Cajun Blake]

Skeeter is spot on

the loaded cartridge case is the gas seal in the chamber. If it expands quickly and fully under high pressure, there is no gas leakage to leave burns. If it doesn't expand (low pressure), powder, gas, and soot get between the case and chamber wall.

It’s important to clean the chamber otherwise powder residue build-up will cause sticky cases

[Roger_Roger]

Skeeter...factory ammo but cheap. Mike.. AR platform and ejects way forward. Blake...got it and will give it a good cleaning..... Tkx for all the quick info.

[Mike D]

Skeeter...factory ammo but cheap. Mike.. AR platform and ejects way forward. Blake...got it and will give it a good cleaning..... Tkx for all the quick info.

Those look like 6.5 Grendel cases to me. They are typically overgassed which would explain your cases being pitched well forward of your shooting position.

Try an adjustable gas block. Close it off completely and open it 1/4 turn at a time until it ejects reliably, holds the bolt open on last round and then add a 1/4 turn. You should se a noticeable difference.


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[Roger_Roger]

Try an adjustable gas block. Close it off completely and open it 1/4 turn at a time until it ejects reliably, holds the bolt open on last round and then add a 1/4 turn. You should se a noticeable difference.

This is a 224 Valkyrie shooting 75 gn American Eagle TMJ. Rifle length gas system, cant adjust this one so whats the next step? I'm not an AR guru but sure like make it a shooter, two will touch then a flyer.

[Mike D]

Burn on case

This is a 224 Valkyrie shooting 75 gn American Eagle TMJ. Rifle length gas system, cant adjust this one so whats the next step? I'm not an AR guru but sure like make it a shooter, two will touch then a flyer.

Replace your gas block with an adjustable one. Pitching brass well forward of your shooting position is a pretty good sign you are getting too much gas. They should throw to between 2-3:00 in relation to your shooting position.

A side benefit is it will shoot a little softer as well.


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[cblackall]

Not sure if you’re shooting suppressed, but that will gum up cases in a hurry. If not, the other replies are spot on.