7.62mm

[Tenntrapper]

To directly answer the OP's question, you can safely shoot 7.62x51 in a .308.

Expanding on that answer, you CANNOT safely shoot .308 in a 7.62x51 chambered firearm.

Years ago, I had a Spanish fr8. It was chambered in 7.62x51. All I ever shot in it was 308. I don't know why, but the bolt wouldn't close on 7.62x51 ammo. Also, being built from a LG ring Mauser, I wasn't to concerned with pressure. Had it been a fr7, I wouldn't have done it.

 

[Woodman]

Found this in a search for "7.62 Nato vs .308 Winchester".......pretty much confirms the above posts, ( must be so, 'cause I found it on the internet ):

https://www.topbrass-inc.com/blogs/news/308-winchester-vs-7-62-nato-what-s-the-difference