Receivers and methods for forming such receivers

A receiver (130) comprising:

• an interior space (136) comprising a longitudinal central axis (112) and a receiving end (138);
• a first set (117) of first structures (120a);
• and
• a second set (119) of second structures (120b), wherein:
• the first structures (120a) extend within the interior space (136) of the receiver (130) in a direction normal to the longitudinal central axis (112) of the interior space (136);
• the second structures (120b) extend within the interior space (136) of the receiver (130) in a direction normal to the longitudinal central axis (112) of the interior space (136);
• the first set (117) of the first structures (120a) and the second set (119) of the second structures (120b) are each half as long along the longitudinal central axis (112) of the receiver (130) as the interior space (136);
• the first set (117) of the first structures (120a) and the second set (119) of the second structures (120b) do not overlap along the longitudinal central axis (112) of the receiver (130);
• the first set (117) of the first structures (120a) is positioned closer to the receiving end (138) of the interior space (136) than the second set (119) of the second structures (120b);
• the first set (117) of the first structures (120a) has a first axial compliance coefficient along the longitudinal central axis (112) of the interior space (136);
• the second set (119) of the second structures (120b) has a second axial compliance coefficient along the longitudinal central axis (112) of the interior space (136);
• and
• the first axial compliance coefficient of the first set (117) of the first structures (120a) is greater than the second axial compliance coefficient of the second set (119) of the second structures (120b).