And powder selection!!Answers to your question will vary depending on barrel length and chamber dimensions.
What's you're load info on the 140's@ that velocityI'd say 3,000+ area for 120s. I shoot 140's at 2850/2900 out of a 26inch.
That makes sense.30" Bartlien, 140 ELDMs
48 grains of RL-26
3000 fps+
That makes sense.
I'm running 47gr Rl26 22" barrel for 2740fps