Can slugs be shot in a shotgun w/ a turkey choke tube??
Will shooting a slug w/o any tube damage the threads in the barrel??
The constriction on a turkey choke tube is very tight and
NO I wouldn't shoot a slug through it.
And yes, shooting a slug w/o a tube in it will damage the threads in the barrel.
If you want to shoot slugs, you need an improved cylinder choke tube (some shoot well with a modified choke tube) or a rifled choke tube for saboted ammo.
IF, your barrel is backbored (and many shotgun barrels are today), you shouldn't shoot slugs in the barrel regardless of choke.
Jim