On a purely cost basis, you will likely have to reload 1000-1500 rounds of big bore rifle to break even on a basic reloading setup. It sounds like you are shooting ~300 rounds a year, so if you stay in it at that rate for 5 years, you'll start to pull ahead.
Some things to consider:
-Nobody stays at the same rate for 5 years. You either get into it and shoot more, or life gets in the way and you shoot less
-Nobody who gets into reloading shoots at the same pace. The amount of shooting you do tends to go up. Unless of course range access is your limiting factor, in which case it is your frustration level that goes up.
- Nobody stays with a basic reloading setup for long, unless they aren't using it.
- Cost of ammo aside, availability is a huge plus to reloading. While everyone else is at home crying that they can't find .17-50BMG rounds at Crappy Tire since Obama got elected, you'll be throwing a couple hundred together in your basement for some informal blasting.