The old bottles that were actually made to be refilled were much more heavy duty than today. Used to be if you ordered a bottle of Bud in a bar, it was put back in the case when you were done and went back to the brewery to be cleaned, sanitized and refilled. Compare the bottles you got to a sixer of craft beer from the store with non-screw tops. The old ones will be thicker, darker and probably a little scratched up on the outside. If you got them, you scored some good bottles.
Non-screw top bottles of craft beer are great to reuse for homebrew but not really designed for reuse. We all do it though. One thing that helps is to be careful when capping them. You don't have to strong arm the crowns. You will know if they are going on right quickly. It also helps to be careful handling them and not knock them around. Lastly, it doesn't hurt to store them in a sealed container like one of those plastic bins. If one lets go, it will be contained.
By some miracle I never had a bottle bomb. I have had some gushers and broken the top off a few while bottling.
Next step is getting kegs of course.