Tweaking some more...
Apparently Raiko and RaikoMX do not entirely share a gun. Raiko does poorly against them, and it is Raiko's gun it uses. So I don't think it is a movement issue exactly. I know RaikoMX's page says it shares the gun, but there might still be some slight differences between them.
Sorry for pushing you down further, but if I can do it I am pretty sure you can do it to. After all you have been doing it longer.
Anyway I want to get to 8th before I start on a gun. Broken record I know, I want to get to 20th... to 15th... to 10th... I'll write a gun eventually!