There is several possibilities
Try wiping between shots most of us do but with APP I can get a second and third without any great strain.
# 1 the only differance between SST's and Shock Waves is the sabot,the SST has a sabot that is about like a MMP 12 the Shock Wave is in between the 12 and the 24 so if the Shock Wave dont fit try the MMP HPH24 if that is to thick try the Harvester Chrush Rib. Lee