Step #1
Draw a rectangle, circle & a shape for the grip as shown.
Step #2
Enhance the grip.
Step #3
Draw a shape between the neck and grip as shown.
Step #4
Enhance the rear sight.
Step #5
Enhance the front side.
Step #6
Enhance the front side as shown.
Step #7
Draw the bolt & receiver.
Step #8
Draw the trigger guard.
Step #9
Draw the trigger.
Step #10
Make necessary improvements to complete the drawing.