Game has projectile mass for MK258 shot marked down as 0.1 kg or 100 grams. The mass should be 0.23 kg according to General Dynamics and Nammo (the producers of the ammunition). Projectile velocity in-game is accurate. Here’s the link to my source: https://www.gd-ots.com/wp-content/uploads/2020/01/30x173mm-Ammunition-Suite.pdf
If this is a balancing thing because doubling the projectile mass might cause the round to be too powerful then I understand.