Open a sketch on the flat end of the pin, and sketch a circle.
Select the circle and the outer circular edge of the barrel, and add a Coradial relation.
Click Extruded Boss/Base
on the
Features toolbar. Select Blind
in End Condition, set Depth
to 3, then click
OK 
.
To add a dome to the head of the pin, click Dome 
on the Features toolbar.
Select the flat face of the pin for Faces
to Dome 
, and set Distance
to 3. Observe the preview
of the dome. Click OK . This completes the pin.
Click Edit Component
on the Assembly toolbar
to exit edit mode.
Save the assembly.
If a dialog box asks you to save the document and the referenced models, click Yes.
