Charge time and it was already inaccurate before they made fusion rifles less accurate. But mainly charge time. If you put accelerated coils you have to get rid of either perfect balance or send it and the stability/accuracy/range go way down. It's really just...meh... although it sounds like it should be a beast. Also, praetorians and minotaurs in the raid have void shields so solar really makes no sense to use. Praedyth's Revenge is so much better. Btw, I have had it maxed for several months.