Boowits no go BOOM.

[Carlos Hathcock]

I may have figured this out but guess I'm looking for some confirmation here. Only thing I changed in this last set was I accidentally over bumped shoulders. Everything else was unchanged. Almost half my loads failed to fire. Solid primer strikes.

My un fired cases measured -.007" to -.0075" shoulder bump vs the fired cases. Tested the primers from the same lot (hammer test), all fired.

My theory is there's just enough slop on the case / bolt fit to allow for some primers to go with others not. My primers typically seat around .008" deep in the pocket, which has never been as issue with this brass or previous. With that depth and slop I'm guessing I was right on the edge of go or no go. What say you?

 

[meketrefe]

They look like well seated and the protrusion good enough but it is not easy to say by the pics and large match primers tend to be
a harder cup that normally need a good hit so you are right those 8-9 thousands could make the difference between the primer
igniting or not.
In this case an easy fix is to remove the bullets and create a false shoulder by using a larger mandrel like a 7.62 and then the 6mm
but stop short only neck sizing. Then put the powder and bullet back in.
might need to anneal to avoid splitting the neck and be careful de-priming a live primer (very slowly).
Another alternative is to stick a small band of aluminum duck tape on one side of the shoulder and hand feed them for a 2nd try.
After remove the tape and will create an uneven space in the shoulder but will preserve headspace and will not have an impact
on a future load as it will fireform itself in the next load.
just make sure the aluminum thinkness is enough and comes out with the case otherwise pick it from the chamber with some tweezers.
I would just put the tape on a clean plastic sufrace and cut a little piece with the razor.
Good luck.

 

[meketrefe]

BTW.... I like your hat. Nice tangent ogive! lol

 

[Carlos Hathcock]

Thanks boss. Will do.

Oh, and the hat is the first prototype from Sierra. Its their new "Sierra Ass King" line.

 

[tony]

If your loads are NOT max loads you could pull the bullets a bit then re-seat them to just engage the rifling. Doing this will hold the case against the bolt face. After firing the shoulder will also be back where it belongs. I have done this and it worked fine but my loads were in the middle of the loading data min/max range.