I'm looking for iron sights for a Glock 40. It is going to be a hunting and long range (out to 100 yards) pistol, so I want to get sights that are good for distance. I have seen trijicon hd xr, I like them but can not find them in stock. Will I need to get different sight dimensions than I would...

So I am looking to get a rifle that I can use for long range competitions, but I'm not sure what caliber I should get. I know there are a lot of choices out there, so this may be difficult. Two things to keep in mind are 1) a round that can go 500+ yards and 2) something that is common. These...