SenSen55, Take off the Celestial Nighthawk and try again???

Okay- but for real, it might be your read-writes got screwy. It sounds like it might be running into an animation error thinking you have simultaneously fired both your first and last shot. Check the read-writes first and see if there is anything to compare it to or just start clicking and see what works. Be mindful that it's the gun's read-writes or you're gonna have issues with the rest of your avi, especially if it's quest.
If the read-writes don't fix it or make it worse, re-start the project and make sure the animation files are where they need to be. There might be one missing for the 'rest of the bullets' and that become an animation creation thing that you can look up on Youtube. (Aka; this long af now- the rest is on Youtube.)

i can only get it to fire one shot

Spam Spam, all you gotta do to install is drop the spades prefab onto your avatar then position the hip, left hand and the right hand components to fit correctly to your avatar then move those components under their respective places in the avatars armature (hip component under hips, etc.) just make sure you have vrcfury installed or it wont work properly

there a tutorial or?