300 black out cracked case necks

[Demoman]

Bought some apex ammo 300 black never used them before had three cracked case necks it is loaded in star line brass seemed kind of hot but new caliper to me will try something different but. It is a new barrel chamber issue gauged go or reading too much into it

 

[steven grammont]

Do you speak English?

 

[whacko]

Starline brass has a good reputation.....so....

That chamber may be too big.

 

[rewster]

Bought some apex ammo 300 black never used them before had three cracked case necks it is loaded in star line brass seemed kind of hot but new caliper to me will try something different but. It is a new barrel chamber issue gauged go or reading too much into it

Did you ever THINK that using punctuation would assist the reader ??!!

 

[Demoman]

Did you ever THINK that using punctuation would assist the reader ??!!

Never did. Comes out as the ramblings in my head. Will try better.

 

[Devils Paintbrush]

You might be able to make some of your own to see if you can mimic dimensions.






View: https://youtu.be/1a55BWiEmSU?si=jIhc4mCD4Zp8qaan

 

[BTSDOG]

The way the primer is cratered in pic 2, leads me to believe there is an overpressure issue here. I never heard of Apex ammo. is it remanufactured ? i would buy some brand name ammo, fire a few and compare cases.

 

[Mesatchornug]

The way the primer is cratered in pic 2, leads me to believe there is an overpressure issue here. I never heard of Apex ammo. is it remanufactured ? i would buy some brand name ammo, fire a few and compare cases.

Apex is targetsports house brand

 

[50wt]

Is it normal to see roll marks on the inside of the neck from the cannelure ? Thin neck wall or super heavy crimp maybe.

 

[akma]

Look for a shiny ring around the case near the base. That would show if headspace is excessive.
I have splits like that when the brass has been work hardened. Also I've had some Norinco 223 stuff from way back that was notorious for splitting like that.

 

[42!]

You might be able to make some of your own to see if you can mimic dimensions.

View attachment 945271

View attachment 945272


View: https://youtu.be/1a55BWiEmSU?si=jIhc4mCD4Zp8qaan

Could you just measure one of the fired cases? The idea is that the case expands to the chamber size when fired. I know brass will flex back a little, but if it still measures over spec, then the chamber is definitely over spec.