The main point that the anti-evolution side continually miss is that the
point of most experiments where flies are subjected to hard radiation is to damage genes not to produce beneficial mutations.
Hard radiation can produce deleterious mutations which can be subsequently identified in later generations, Wieschaus and Volhard's seminal screen looked at mutants showing in the F3 progeny of a mutagenised population in order to identify embryonic lethals and genes whose mutation lead to the disruption of normal patterns of cuticle development. I'm not sure if radiation was actually used for this screen, chemical mutagenesis seems more common in the literature.
Given that these experiments are not designed to look for beneficial mutations or to produce new species I do wonder why creationists et, al. continually bring them up as having 'failed' to do so.
TTFN,
WK