Good Morning all, As for answering the question whether transitional ballistics should be a sub category for external ballistics I believe they should be kept separate because it is a great transition from being inside the barrel to exiting the barrel because it requires a lot of thought on how the round will stabilize outside of the barrel with environmental obstacles in the way. The trajectories of older cartridges such as those used in historical military or sporting rifles can be altered or affected in various ways over time. For example Older cartridges are often reproduced today with modern smokeless powders or handloads that differ from their original specifications. Some handloaders or manufacturers use more efficient powders that increase muzzle velocity, resulting in a flatter trajectory. Though that being said, some loads are downloaded for safety in antique firearms, leading to slower bullets and more arcing trajectories. Like .45-70 Government cartridge originally used black powder, which produced about 1,200 fps. (Guns&Ammo) Modern factory loads can reach 1,800 or more fps, which dramatically altering its trajectory. Another thing that could affect it is the length of the barrel and the condition it is in. Shorter barrels reduce velocity resulting in more bullet drop. Worn barrels can decrease velocity and accuracy, altering expected flight paths.(Guns&Ammo) Though there is many things that can affect it in my opinion these two things that I have listed is most important