Hard to know. Different Component = Different Pressure. Compare the 300 gr N110 load data for Hornady & Sierra bullets. Big difference. Out of a 4" barrel, 1200fps sounds better to me if the accurace is good.
http://www.lapua.com/en/products/rel.../relodata/6/21 Seems like your 21gr load has 1 of the pressure signs listed here. #16
http://www.shootersforum.com/handloa...ure-signs.html