I use both. The bolt guns TYPICALLY run more powerful rounds than AR's and rarely need follow up shots on same dog. As said after 1st shot you swing to second dog and wait for it to stop, shoot and then worry about 3rd or back to the 1st. The bolt guns are more at home on longer shots due to that additional knockdown etc. Even with lighter calibers, the bolt guns usually run longer barrels which also "wake up" calibers like the .223 and give them critical velocity gain. The additional knockdown minimizes frequency of runners even on poorly hit dogs and gives a bit more forgiveness that you need with slower follow up shots.
The AR-15 usually have short barrels with less case capacity to work with light calibers (due to pressure and powder capacity limitations)which severely limits their velocity and effective range. It is a better mousetrap inside normal calling ranges, but does require follow up shots a lot when hit poorly and proportional to the range...When hit where supposed to, even at 375yds they go down. When hit poorly in guts, they run and sometimes never found.
I've never owned an AR10, but my speculation is that you get faster followups with heavier calibers, but at the cost of heavier gun and higher cost. The downside is that you almost have to run a Suppressor(more money) with their typical short barrels with large amounts of powder to mitigate muzzle rise/flash/deafening sound. The shorter barrel vs bolt gun will also cost a large loss in velocity, offsetting it's beneficial knockdown somewhat.
In my experience, Thermal on a long barreled 24" AR in .223 is a good compromise with quick follow up shots (when they stop just like the more powerful bolt rifle), but the notion of shooting running dogs with a Thermal on either is just wishful thinking. Each and every trigger pull on moving dogs is pure luck(despite what guys want you to believe). The "latency" or "lag"(not the refresh rate that many try to think it is)varies continuously dependent upon how much info it's trying to translate and display on it's mini tv screen.
I think inside 100 yds, woods, tight areas, I'm taking AR-15 with a short barrel. In open fields I'd opt for the bolt gun and more speed from it's longer barrel/caliber.
As a compromise I'm currently running a 24" AR in .223 and of the 50 or so I shot with confirmed (but probably marginal)hits on last year at various ranges, and I recovered 39 of them. I just accept this is the nature. I shot 4 with .243 and missed several but of the 4 I hit I lost only 1. I hit him and he dropped and was un-concious for 5 mins, while I focused on 2 others. Went back to him and he started trying to stand, sent a second one and thought missed. Next day went in to find him and kicked him up. Didn't bring a gun because of blood everywhere I followed. Anyways, killed him a week later and he had a bullet wound on each side of neck where they grazed him and it was healing.
