Thread: Low velocity and pressure Howa 223

I recently picked up a Howa 223, put a few loads together and finally got out to test earlier today. I picked the 73gr ELD-M as it seems to shoot well for many people, and 2208 as it’s what I had on hand.
I consulted ADI data and setup a profile in GRT which suggested I’d be hitting max pressure around 2750 fps at 24gr of powder in a 20 inch barrel. I loaded a couple of charges for reference, at 23, 23.5 and 24 gr at a COAL of 58.5mm However, on testing, all velocities were about 150fps short of where they should be, with 24gr barely pushing 2600 fps. They shot well enough for my purposes, but the low velocity is puzzling.
If there is a linear relationship between pressure and velocity, does this mean I can keep increasing my charge weight toward my expected velocity? Are some barrels just slow? (I’ve used this same batch of powder in another load that was ok, so don’t think it’s that).