We could be more helpful if you would provide more specific question. Projectile examples in help can be a good start as DanStro suggested (2.1.3 RIGID PROJECTILE IMPACTING ERODING PLATE, 2.1.4 ERODING PROJECTILE IMPACTING ERODING PLATE for Abaqus 6.10-1). However, here is few steps how to do it:
1. Create parts either in Abaqus either with other software and then import in Abaqus.
2. Create an assembly in a way that bullet is in a position right before the impact.
3. Define boundary conditions: probably wall or other structure had constrained nodes, and for bullet CREATE PREDEFINED FIELD - impact velocity.
4. Define contact. General contact is much better for impact problems and much easier to model than contact pairs.
5. Of course you will also need appropriate material properties.
Do you expect bullet penetrating through the material? If so, I would suggest you to read this
. However finding appropriate material properties do describe damage of the material will be pain. You can find some properties for aluminum, steel and titan with uncle Google, but anyway these parameters must be tuned for your specific problem.
Good luck and let as know about your progress.