That would be at least a 2 hour drive from Horseshoe Bay, if you break some speeding rules. Closer to 3 or 3.5 hours really.
Stave Lake was an option many years ago but idiots messed it up with dangerous shooting (including a guy seeing a .50" round going right through his cabin before evacuating with his family), littering, and other idiotic stuff that idiots do, so no shooting there any more.
Unfortunately, given our forest and mountain landscape, there aren't a lot of options. The range in Lynn Valley would have been perfect, but they shut that down decades ago. Was good to 800 yards I think. Finding a spot with even 100 yards clear between the trees can be challenging in local crown land forests. I wish you luck. And from previous threads on this subject over the years, I'd say you have very little chance of anyone who does know of a spot being willing to share. The risk of it going the way of Stave Lake is just too great.