Ball and Chain — J.R. Roberts

THROUGH RAIN, SLEET, SNOW, OR A HAIL OF BULLETS...
On his way to Oregon, Clint Adams takes on a side job as a mailman. Normally he wouldn't agree to such a task, but it is for his friend and barber, Ned Smith.

Clint soon discovers that this small favor for a friend is going to be big trouble. The parcel to be delivered to Hinterland is a piece of art by Ned, who has quite a following -- of gunmen. But those pursuing the Gunsmith will soon learn that lead doesn't paint a pretty picture...