Until you learn to use a (2 point) sling properly to build a good sling supported firing position you'll never believe the benefits. Not just in decreasing group size but in rapid return to your point of aim for a follow up shot. Shooting M1A's and M1 Garands fairly rapid fire at multiple targets at multiple ranges convinced me of that several years ago.
It's a practice thing. The more you do it, the quicker it gets. The more you do it, the less you have to think about doing it. The more you do it, the better you get at shooting a rifle.
If you get the time, do some reading on the US Marines, WW1, Belleau Woods. Their rifles were standard 03 Springfields. The ammo was GI issue ball ammo for that time period. The difference was that US Marines were taught to shoot with a sling. They also go an extra bit of pay each month based on their qualification records with those 03's. Not much, but hey, a few extra beers Friday and Saturday made it worth it.
There was close to a thousand yards between the woods the Germans where the Germans were dug in and the woods were the US Marines were dug in. In between had been a big wheat field planted/harvested by French farmers. The Germans tried to cross that field several times that first day. The Marines started killing them at over 800 yds. The fire from the Marines was so accurate/deadly that the German officers reported to their higher HQ that they were facing a battalion of snipers on the other side.
Slings, man. They really do help.
