The grenade launcher is the same (or almost exactly the same) as it was in COD4. 155 to 25 damage with a 300 inch range. Only about 1.8m of its 7.5m blast radius is lethal. In comparison, about 4.5m of a Frag/Semtex's 6.5m radius is lethal.
With the damage boost from Danger Close, the lethal radius is increased to 3.3m. Blast Shield cancels out Danger Close, so the lethal radius is back down to 1.8m. Without Danger Close, anything less than a direct hit against a Blast Shield would not be lethal to a guy at full health.