Most people think that low brass shells are lower pressure, and it simply isn't true, unfortunately.
The only ways to know if a load is low pressure are 1) to load it from a tested recipe, or 2) send 3 to 5 loaded shells to Tom Armbrust or someone who has calibrated pressure equipment, or 3) to be provided the pressure by the manufacturer -- or to get results providing item 2 or 3 from a trusted source.
Factories save $ by using as few grains (weight) of powder as they can, while making loads that meet SAAMI standards. This usually (but not always) translates to fast burning powders, produce near-max pressures.