Review on Hillman Group 556 1 Inch 12 Pack: Heavy-duty Hardware Essential for All Your Projects by Fernando Beck

This is the correct diameter you need for your sighted gas block. You'll need to trim the end off a bit as they're a bit longer (1/4" IIRC). You should always use new pins when removing the front sight block. It's much better to have a dozen for $10 than 2 for 7 $, how other sellers calculate "Taper Pins AR".