Imprecation isn't that hard, I'm average at pvp and I got it done in 1 match. Besides if you can't land this step with imprecation and hate the gun you'll hate the first curse, first curse is a beast but only for those who can land headshots. Easy way to solo this, use nightstalker, vortex nade, black hole, envenomed, lock down and keen scout. Use smoke and nades to slow and weaken then follow up with the headshot, makes it simple. Save shadow shot for groups and clean up multiple kills. Most say to do Clash or rumble, I did it on skirmish, just found it easy.