My guess is that they are marking up the Remington as a handling charge.  The 220 gr rounds appear to be using Hornady bullets... and I'm guessing Remington brass.  The 180 gr also appear to be using Hornady bullets.  I'd hazard a guess that they are pricing based on their cost of brass and bullets!

I can reload for pennies as compared to this ammo... but I'm sure there are shooters out there who don't reload, and would just assume buy loaded ammo, regardless of the cost!