If the space around the bolt is fine, then the bolt should be good until you find a proper M7 set screw.
The advice is to make the bolt the ground lug one, meaning if the missing set screw is on the power or speakers, move the set screw of same size from the ground over to the other terminal, and then use the M7 bolt for the ground wire tightening.
That way, if the ground 'bolt' is accidentally grounded to the chassis of the car or the amp, or whatnot, it does not matter...no current will flow as it is already at ground potential.
Again, if they are all m7 connections, make the ground connection the one with the bolt. You'll be fine that way until you get to finding a proper M7 set screw.
The advice is to make the bolt the ground lug one, meaning if the missing set screw is on the power or speakers, move the set screw of same size from the ground over to the other terminal, and then use the M7 bolt for the ground wire tightening.
That way, if the ground 'bolt' is accidentally grounded to the chassis of the car or the amp, or whatnot, it does not matter...no current will flow as it is already at ground potential.
Again, if they are all m7 connections, make the ground connection the one with the bolt. You'll be fine that way until you get to finding a proper M7 set screw.