RG-42 is a ww2 era design that relies on natural fragmentation. it has no PFF, it has rolled steel sheet fragmentation liner with no indentations or anything that would aid in separation of fragments. that thing has pre-cut steel cubes, Spike uses tungsten cubes, steel balls or cylinders (soviet designs) are often used too. natural fragmentation results in wide range of fragment sizes, with either too small (and braking on air, causing no significan injury) or too big (produced in small number and missing intended fragment). RG-42 and to lesser degree RGD-5 fragments are just pieces of steel sheet, so few tens of meters away it’s just angry glitter, because it brakes on air rapidly due to nonaerodynamic shape