Gallery Range design has changed little since the beginning of the 20th century. The targets and those operating them are protected in a concrete lined, partially roofed gully called the gallery. A large mound of bullet absorbent material (in Europe earth and grass) protects concrete gallery from bullet strike; this structure is called the mantlet.

As technology progressed, electro-mechanical targets were placed on top of the mantlet to make training more effective and less manpower intensive; these ranges were called Converted Gallery Ranges.  The converted ranges brought an inherent safety problem in that when the new target mechanisms were being maintained, the wardens were in danger of falling into the gallery.  A ballistically safe solution had to be found.

Once the solution was found, it was essential that the processes be required in the Landmarc Assignment Instructions