A string broke on my Gibson SG, so I had my step dad send me some guitar strings in the mail thinking he'd go to Guitar Center and buy me some D'Addario strings like he always does. Instead I ended up with a pack of Fender bullet end strings which I'm not familiar with. Are these strings compatible with SGs or will they only end up damaging them?
They will work just fine in your SG. The bullet-shaped end on the Fender string was designed to fit better inside the tremolo block of a Stratocaster. The idea was that after you hit the tremolo arm, the bullet-shaped ends would return to their starting positions inside the tremolo block more accurately than regular ball-end strings.

A lot of people use Fender Bullet strings on stop bar and string-through-the-body bridge & tailpiece setups.
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