It seems with a standard AR-15 GBL (Golf Ball Launcher) range will vary from 150-500yds depending on how much you believe the story

The fastest speed a golf has been recorded at is just over 200mph (~290fps) which is slightly faster than a M79 round at 250fps, what speed the GBL fires one at is any ones guess but I would think it's about the 250fps mark.

M203 for your Steyr, Mark? The 203 for the Steyr is known as the GLA or Galah! :lol: