First, good job on the defensive position. I hope next time it goes smoother. Skip the 45 rimmed idea, there's a safer alternative. There are 410 ga slugs available. You will have all the power you need in a slower moving projectile that won't have as much overtravel potential. To find some you like do a google search on 410 shotgun slug. The first couple results have them at decent prices. You can also get buckshot loads for the same round. They have 3,4 or 5 balls in each cartridge. If you think you may "jump the gun" a bit again, I'd suggest those instead. It doesn't sound like you need a scope, you have the ability to get them close enough. Also, they may have to tendency to scare into shyness, but it won't last. Over time, after being scared off, they will come closer and closer testing the waters. You will have to refresh the threat occasionally. If they keep not getting food at your place, they may move on, but when other supplies run out, they could return to try again.