A: Sheetrock - sure. Concrete - ehh probably not. If it is in fact concrete then you should look for masonry drill bits.
A: The magazine handles nails that are 20˚ angle.
A: Yes you can but make sure you go slow
A: While the bits are not exclusively used with DEWALT, on that you would need to contact the manufacturer of the drill to verify.
A: The drill bits included in DWA1184 are round shank bits. These bits are compatible with a regular drill chuck.
A: Most common sizes are doubled up