Agree a heavy rifle can be held steadier. Barrel heat with a 223 that has roughly half the powder of say a 308 and 1.4 less internal barrel surface to transfer heat will be way less than say a 308. Maybe a 223 sporter could be similar heat wise to a varmint 308?? Fatigue, also less with less recoil.I'd say the heavy rifle is inherently more accurate for rapid fire for two reasons:
- repeated recoil introduces fatigue into the shooter, which leads to a deterioration in recoil management
- repeated firing heats up a skinny barrel fast, which changes the harmonics in an already flexible lump of metal, which change the point of impact
I think a lightweight 223 is a good way to start shooting and maybe getting rid of some bad habits. Even wind effect is much more visible with a lower bc bullet, one can learn more.
I love plinking at longer ranges in high winds with the 223, you really see the effect of the wind.
edi



