300 BLK reloading adventure

[Control for Smilers]

Any particular head stamps doing this? how many reloads before this starts happening?

 

[rbstern]

And have you trimmed the brass with an appropriate trimmer/length gauge?

 

[C'mon man!]

Have you measured the shoulders on these cases and compared them to cases that fired fine? Do you think it could just be a firing pin issue, maybe needs broken down and cleaned?

 

[1006]

Measuring the shoulders is my next step…I do not trim the 300BLK, the Ruger chamber is generous.

I did disassemble the bolt and firing pin, and cleaned, as well as measured firing pin protrusion from the bolt face.

 

[rosewood]

The chamber may be rough gripping the brass and not allowing it to slide back to fireform maybe??

Could you be running to low of pressures in it? Primers backing out is sometimes caused by low pressure, not enough to drive the case back against the breech face to re-seat the primer after firing.

If you determine you have a headspace issue, that is something Ruger needs to fix. Do you know anyone that has 300BLK go/no-go gauges to check it?

Rosewood

 

[1006]

Although this discussion went in the direction of possible headspace issues, the root of my problem turned out to be hard primers. I have found a number of converted 556 cases to be out of spec, with the shoulder pushed back too far.

I have edited my posts to reflect the actual outcome.

 

[1006]

And all of my misfires eventually fired when re-cocking the gun a second time, those misfires produced the brass with backed out primers.


Live and learn…..thank you all.

 

[rosewood]

All I have ever used in my AR and my CVA Scout in 300BLK is converted brass. Maybe the person that converted that brass either cut it too short or the gun it was fired from had very minimal headspace and they pushed the shoulder way back.

Rosewood

 

[Control for Smilers]

There might be a quick answer that should have jumped out at me sooner. After sorting the fired brass with backed out primers, all the backed out primers are on 5.56 or 223 converted brass. The shoulder does measure slightly lower. The factory 300Blk brass seems to work fine.

That is the answer i was looking for. Anneal maybe?

 

[1006]

That might work, but I believe I will just toss them out, and stick with 300BLK Factory brass from here on out.