Wow. All the down votes from you Yanks. I'm Australian and the last time I shot a "gas" gun was over 20 years ago. I don't feel like I need one for two reasons. 1. I shoot at ranges I know I am good at - i don't go for hail mary shots no matter how tempting as my aim is to put the animal down quickly and cleanly (there's no one around to boast to anyway but my mates will shake their head if they see a badly aimed shot on the carcas). 2. Bolt actions from ny experience are fine for a follow up shot if needed - as I'm shooting with a margin of error for range I have enough time to get another shot on target if needed, but more often I only need one shot.
Look I don't have any idea as to your semi autos.. when I was young I had a lot of fun with old Vietnam ordinance - SLRs in particular and a great mate had a Bren Gun which was super fun (especially as it used easily found 303 ammunition). One of my friends even had an old vickers machine gun they used to strap to their ute (truck) to cull kangaroos (biggest herds of roos on their 250,000 acre property can get up to 100s of 1000s).. but none of these were hunting guns and none killed ethically. My family's rifles are tools and its the hunt that's fun not the number nor speed of bangs. Best hunting Ive done is with my uncle on his 400,000 acre farm/property over many many days...
Anyway, downvote away.. all i can say is it makes me realise how different we are...