If you go up to Summerland, and head towards the KVR and garbage dump, you should be able to find your way onto the back road that goes all the way to Princeton. Drive along there for a few clicks. Eventually you'll see a very flat section on the left. There's a bunch of stuff that people have used for targets, you can kind of see it from the road - but what will stand out is how it is fairly flat compared to the rest of the terrain. There's probably around 200m+ that you can shoot into a bit of a mound away from the road. There are a couple of trees, and I don't know if they limit the usefull shooting range much, I've only shot my .22 there. There's also going to be a lot of junk that people have shot at - computer, DVD player, lots of glass. There's a gong set up on the mound.
If you don't know the area that well I could probably give better directions if this sounds like a good place for you.
BTW, when I started shooting, I bought a hand thrower, and returned it that day for a spring loaded one. It was really tough to the the hand thrower to release properly. You'll likely have way more fun with a spring loaded thrower. It's probably the best shooting investment I've ever made, I've gotten so much use out of that $95.
If the hand thrower is working for you, by all means.
Oh, I go up to Pentiction quite a bit to stay with a friend, was thinking about this weekend, you wanna carpool or meet up if I do end up going?