39 shot per meter (spm) size
The gun itself exploded because the well bore
was not filled with fluid at the time of detonation.
The blue object is a plastic coated rod coupling. Above it, in the half pipe, is a similar coupling which has had its coating worn off due to the friction of rotation in the midst of produced sand.
A worn rod coupling will allow the rod to rotate off centre, perhaps even against the wall of the tubing. Both pieces of tubing (3rd and 6th from left) display this type of damage, called "wire marks"
The other type of damage shown here is to stators (the stationary housing of a rotating progressive cavity pump) The constant rotation accompanied by sand in production can line and gouge the interior of the stator. A dramatic example is shown 2nd from left where pyrite from the formation has entered the stator and the friction has ground away the elastomer lining and deeply grooved the interior metal wall of the stator and produced pyrite balls