Re: 6.8 or 300 blackout
The barrels are usually proofed at 70k. 58K is very much below that. Let alone 60k. But, this has been hashed probably over 50+ times. So, no real need to get into it again. It would just be redundant.
You still listed the 175gr. But, it doesn't matter.
Anyhow, It's...