It has been a while, but I ran some Berger Varmint blts in my 223s on prairie dogs in the late 90s.
The varmint blts characteristically had larger openings at the tip - presumably to promote expansion.
Compared to polymer tipped varmint bullets they didn't expand as well, but they were VERY accurate - to the point of using them in some varmint matches too.
Compared to the 52 gn Sierra Match Kings the Berger Varmint pills did expand somewhat better, but (again) the polymer tipped pills were the "bees knees!"
A 60 grain blt out of a 223 would likely be too slow to really work well. BUT! Out of a 6BR, a 60 gn blt is light and speeds could easily be above 3500 fps (1067 mps). Terminal performance might be explosive - similar to the big hollow points on the TNT bullets.
I'd guess accuracy would potentially be their strong suit. I'm thinking expansion on critters (especially under 200 meters) would be more than adequate; worth a try for sure!! (I wouldn't mind trying them in
my 6BR, as a matter of fact!)
See what you think of 'em, and report back!