I have a late 80's Remington mountain rifle in 280 rem that's been my most challenging rifle to shoot from the bench. It's like looking for hen's teeth to get a sub 1" 5 shot group with any load. I have done 1" 3 shot groups and yes fliers are an ever present possibility. Most of it is definitely technique. Haven't tried any of the cheater methods mentioned above but it may be worth looking into. I usually just try to do my best perfect-shot trigger breaks when shooting on sand bags. It netted me a good 1.5" cluster for 5 shots at 100yds with a new speedster load and I was happy ☺
