A faster burning powder would be a good place to start. Some people like using slow burning powders for one reason or another but you are going to use more of it and it might be dirty if you are shooting light loads.
You could go slightly faster with something like Universal or AA#5 or you could go a whole lot faster with something like HP38/W231, AA#2 or Bullseye. None of them are unsafe. Screwing up by using too much powder is unsafe, but following published load data is safe if done correctly.
New gun, same ol' shot.