... having a PTRS round (btw what IS that AT rifle's caliber?) go through organic material makes me feel uneasy, and that tally on the AT rifle either means vehicle hits or something else.
So, it's not much bigger than a .50 BMG? Wow, and here I was thinking that it was much bigger than that.
Well if you actually compare the two, the 14.5mm is actually quite a bit bigger. Calibre differences aren't based on diameter alone: you also have to figure in the length of the projectile (which increases a lot more for a given diameter) as well as the size of the cartridge.
So, it's not much bigger than a .50 BMG? Wow, and here I was thinking that it was much bigger than that.
12.7x99 is 50 BMG. The first number is the diameter of the projectile in mm (bullet). Second number is the length of the case in mm. Like Alceister said, those two numbers don't give much information on the cartridge alone. The case head (the base of the case) diamter is not specified, nor the shoulder, neck length, taper angle, primer type (not to mention magnum variants). It also doesn't give any clue as to the loading, for example the weight of the bullet (and consequentially the ogive), or powder charge. These latter parts are really what determines the power of a given load. You could load a 50 bmg with a 50AE bullet and just a primer and it would only have as much energy as a 45ACP subcaliber cartridge.
If you ever (or do) take up shooting for sport (or possibly as part of your job), get into handloading (aka "reloading"). You can learn so much about how firearms work and all the cool "unorthodox" things they can do.
