This has been a topic of discussion here lately. I'd like to throw in my theory. I've had considerable experience in rifle accurizing, especially in bedding methods.
I haven't found that there's a significant difference in accuracy between long and short actions, but more with case capacity and other variables.
When you compare short-actions to long actions, Both actions have bolt lock-up directly behind the cartridge and the recoil plate at the same point. Action stiffness varies more between single shot rifles and internal magazine rifles, but not a whole lot when talking hunting-accuracy.
The weakest link in a rifle's accuracy, given equal quality barrels, may be in the bedding of steel to the stock. Poor bedding or weak stocks can make a huge difference in rifle accuracy. (I recently saw a rifle shoot 4" groups with poor bedding, then shoot cloverleafs after pillar-bedding.)
My contention is that the biggest variable could be in the action length and it's bearing area in the stock. A longer action has more contact area and is longer, so should vary less than a shorter action. Think of a handgun with a longer barrel being inherently more accurate than a snub-nosed one. Both frames may be identically accurate, but the sight radius difference makes the difference in accuracy. Larger grips providing better hand-to-gun fit can also improve accuracy.
So, the longer bearing surface, especially in average factory-bedded rifles, combined with the longer distance between scope mounts may provide even greater accuracy than a shorter action. Variations in barrel accuracy may make a greater difference than action length (especially flexible actions with small recoil plates and cheap, squishy injection-molded stocks notwithstaning).
I believe the original Winchester Model 70 had only one receiver length, but had magazine blocks to accommodate shorter cartridges. Nobody seemed to complain about the hunting accuracy of that rifle (out of the box).
I haven't found that there's a significant difference in accuracy between long and short actions, but more with case capacity and other variables.
When you compare short-actions to long actions, Both actions have bolt lock-up directly behind the cartridge and the recoil plate at the same point. Action stiffness varies more between single shot rifles and internal magazine rifles, but not a whole lot when talking hunting-accuracy.
The weakest link in a rifle's accuracy, given equal quality barrels, may be in the bedding of steel to the stock. Poor bedding or weak stocks can make a huge difference in rifle accuracy. (I recently saw a rifle shoot 4" groups with poor bedding, then shoot cloverleafs after pillar-bedding.)
My contention is that the biggest variable could be in the action length and it's bearing area in the stock. A longer action has more contact area and is longer, so should vary less than a shorter action. Think of a handgun with a longer barrel being inherently more accurate than a snub-nosed one. Both frames may be identically accurate, but the sight radius difference makes the difference in accuracy. Larger grips providing better hand-to-gun fit can also improve accuracy.
So, the longer bearing surface, especially in average factory-bedded rifles, combined with the longer distance between scope mounts may provide even greater accuracy than a shorter action. Variations in barrel accuracy may make a greater difference than action length (especially flexible actions with small recoil plates and cheap, squishy injection-molded stocks notwithstaning).
I believe the original Winchester Model 70 had only one receiver length, but had magazine blocks to accommodate shorter cartridges. Nobody seemed to complain about the hunting accuracy of that rifle (out of the box).
