The special gun prepared for Rafael was on another ship, but as an intermediary vessel, there were plenty of guns available, any of which could be used by Rafael.
Rafael's gunmanship was not bad either, which actually was not worth any surprise. For someone who had served in the military and continued to work in military-related fields after retiring, it would be abnormal if his gunmanship were poor.
The main show had to wait until the end. Little Donnie had everything Rafael needed well-prepared: Hexogen, C4, and all other necessary equipment.
C4 is a plastic explosive with less power than Hexogen, but it's like a ball of flour that can be freely molded into any shape. With some sticky substances added, it can be conveniently attached like chewing gum, and it's also very safe, making C4 the most frequently used material.