That looks like a two diameter bullet. What part is sized .311?Yes, the T/L version got plain based.
It shoots great..........Just can't hot rod it.
I shoot the plain base version out of my Tikka , 30-06 Springfield.
8.2 grs. of Amer. Select with a large pistol primer.
Will put three rounds in a ragged hole at 50 yards all day long.
Ben
You get 2000 fps with accuracy with a bore riding bullet? I have read that bore riders didn't do well at high speed. I have no experience, just read a lot.