Re: Range/Bullet trajectory question
The heavier bullet generates more barrel flip, resulting in a higher bore axis angle as the bullet emerges. This translates into a higher POI.
Recoil always takes place, ensuring that the POA is, in fact, always changing during the duration of the bullet's barrel transit. How much depends on each load's individual recoil characteristics/responses, which are not solely mechanical in nature, there's the human component, too. The barrel is essentially never pointing where we aimed it prior to recoil by the time the bullet is released to fly its trajectory. We are picking an arbitrary POA that, combined with recoil and ballistics, results in a particular POI.
The fact that recoil can be so dissimilar between shots, due to our own varying degree of relaxation, etc., is a key part of dispersion, and is also another key reason why I disregard the smaller issues associated with super-anal handloading compulsions. People get so hung up with the mechanical issues associated with accuracy, and pay far too little attention to the shooter's human aspects.
Whatever horizontal displacement occurs stems from similar causes, since recoil takes place along a three-dimensional path. This phenomenon is essential to why LL's advice to get straight behind the rifle is so effective. It is also at the core of why my elbow-on-sling-with-bipod technique works the way it does.
Both techniques modify recoil effect so it becomes more consistent. LL's deals with horizontal dispersion, mine deals with the vertical.
They can be used to complement each other and get recoil down to the point where the more arcane handloading techniques can actually become effective. It all contributes to the single system. We need to deal with each accuracy issue in the order of the magnitude each has on consistency. Until the bigger ones are resolved, resolving the smaller ones is not really effective.
In short, the different POI is a response to different recoil characteristics. While ballistics are also different for different loads, these differences are greatly overshadowed by the recoil effects.
Greg