I have both the Ultimate Sporter (in .177) and the HFT 500. The U.S. is used for hunting only and the HFT 500 is obviously used for HFT competitions. They are both incredible rifles, some of the best that Air Arms have ever produced.
I have set the two rifles up to mirror each other in every possible way, so it doesn't matter which one I am using, the aim points will be the same. They are both incredibly accurate and consistent rifles. I wouldn't want to use the HFT 500 for hunting as I much prefer the shorter Ultimate Sporter which also has the advantage of being whisper quiet with the new Air Arms silencer on it.
Although the U.S. is heavier than my previous hunting rifle (Daystate Huntsman Midas L.E.), I do not find it too heavy for a couple of hours stalking around one of my permission's.
As for the HFT 500, I have only been able to shoot it on a HFT course, twice since I bought it, due to unforeseen circumstances. Both courses were fairly tricky and both scores were in the 50's, good scores for me. The little bit of plinking time I've had with it has proven the rifle to be as accurate as any other I have ever shot. The trigger needed to be set up, but if I can do it, anyone can do it. I also fill both rifles to 170/175 bar.
I honestly can't see why you would want to buy an HFT 500 to go hunting with. The Ultimate Sporter is one of the best hunting rifles available over the counter right now. It comes with two, yes two, 10 shot
magazines, that you could load blindfolded. It comes with one of the quietest silencers on the market. The stock can be adjusted to comfortably fit any shape and size. If you wanted to shoot the occasional HFT competition, then buy a Rowan single shot adaptor and away you go, simples!