Overview
This will prolly get patched soon but its a really fun build to do a couple of viewers and i worked on it on stream (twitch.tv/mGodz13)
How to do it
Basically how this works is by having your Umbra emptied out by holding down a channeled spell, I preffer using Lightning Bolt but you can use the umbra lazer thing or the fire spray
and so while your umbra is emptied keep your finger holding on the lightning bolt at all times and press down on shift to activate attack without actually clicking on an enemy then hold down left click on the direction you want to shoot.
I chose mace because it gave the most damage from the 1 handed weapons (i have not tested 2 handed weapons with it im not sure if it would work with pistol)
P.S. this also works with Melee weapons but is harder to hit things and becomes quite useless
P.S.S XBOW doesnt work with this exploit/glitch
The clip bellow shows how the build in action
[link]