The French used the APAV 40 as a DF weapon Afghanistan.Agreed, but most rifle grenades (according what I've read) are not...
That's true for HE grenades, but I guess a fuse detonated HEAP round will not be too useful, they need to be contact detonated...
And as for flechete, I guess it also must be direct fire (as they act as cannister), otherwise it would be shrapnel, not flechete...