(11-26-2020, 01:00 PM)robkelk Wrote: Question for the story after the one I'm currently working on:
Is it possible to look at a spent brass casing and tell without any context that it's from an AP round for a high-powered sniper rifle? Or is being able to do that a sign that the character is about as realistic as James Bond or Batman?
When dealing with sniper rifles, they typically use cartridges that are used in other weapons, such as .50 BMG, or 7.62mm NATO, just to name a few. There's actually not many that are specialized just for sniper rifles, because military prefer ammunition that is interchangeable from one weapon to another - it really simplifies the supply chain.
Often the manufacturer and type of cartridge is stamp in the bottom of the casing, and I believe its possible to determine if a cartridge has been reloaded with a more high-power propellant from the residue left inside.
Another issue is that, really, any high-powered rifle can be a sniper rifle, provided that it is an accurate enough of a weapon. Larger guns that use .50 BMG such as the Barret are actually referred to as "Anti-Material Guns" since you don't use them on people (except at extreme ranges), but rather on lightly armored vehicles. These are typically derived from anti-tank guns made just prior to WWII, such as the Solothurn S18-1000 which, again, used a preexisting cartridge. Granted, it was one that was used in flack canons, but you get the idea.
The most telling characteristics that will indicate the use of a sniper rifle will be where you find the casing, and where you find the bullet. One thing I think that the TV series, CSI, actually got right was that investigators can determine an estimated trajectory on shots fired. This, of course, requires that the bullet has passed through one object of known placement (windows, the victim, thin walls) and embedded in another fixed object at the end of its flight (a tree, another wall, etc).