Looking through a list of projectiles on an online store can be confusing. Certain things are fairly obvious - for instance, the caliber (.224 in our examples here, as I'm shopping for projectiles for my PS90 as I write this), and the weight of the projectile in grains. But there are a myriad of other things listed in the descriptions, some of which raise the price considerably. Are they relevant? Do you need them? Well, this is where I help you decide whether you do or not.
Armor Piercing. This can have a variety of meanings, although it usually refers to a bullet with a penetrator core. This core is usually a tiny steel or tungsten rod which continues into the target after the lead encasing it simply smushes itself against armor of some sort.
Armor Piercing Incendiary Tracer. Not only does it pierce armor, but it draws a pretty line to the target and delivers its flaming payload to its target.
Boat Tail. Instead of a flattened base to the projectile, it tapers in a little at the rear. This provides a more aerodynamically correct profile, with less drag.
Double Struck. This is where the bullet is resized again after it's been plated, which results in a bit more uniform size.
Flat Base. This is simply a way to say "not boat-tail".
Full Metal Jacket. The bullet is completely coated in copper. The copper is a 'sacrificial metal', which is sliced up as it travels down the barrel and frequently shed outright.
Flat Nose Soft Point. The bullet's nose is flat and the bullet's lead tip is exposed. Not really sure what this would accomplish in a rifle round, but it's pretty common to see in handgun projectiles.
Hollow Point. The tip of the bullet is hollow, so that when it strikes its target, it will fragment into pieces, instead of deforming into a large lump and sliding around. Commonly used in home defense rounds.
Hollow Point Cutting Edge. While the name sounds as if the round is perhaps semi-AP, all it means is that it's from a product line Lapua is very proud of.
Soft Point. Instead of being completely copper-coated, like an FMJ round, the soft point bullet has the lead (or other material) at the very tip exposed. This ensures that when the round strikes its target, it'll be more likely to expand.
Moly Kote. Molybdenum Disulfide is sometimes applied to bullets as a lubricant. It is thought to make them easier to seat reliably in cases, and to make them shoot more accurately. If you actually need MK, you will know you actually need MK.
Power Lokt Hollow Point. An HP projectile where the copper jacket has been electrolytically plated onto the lead core.
Power Point. A Winchester variant of Soft Point.
Spitzer Boat Tail.
Semipoint. In other words, a bullet with a blunter tip than your typical Spitzer tip. I consider this definition a little suspect - information was very sparse.
Triple Shock Xtreme. This is a Barnes designation of a premium bullet design, which has three grooves on the back of the bullet. More information can be found at the Barnes website.
Wad Cutter. Typically this just means a flat-nosed bullet, as it cuts very clean holes in paper. Commonly encountered in pistol calibers. See below, however, for an alternate meaning.
With Cannelure. I have seen this written without the slash at times. The cannelure is the small grooved ring around a bullet, which is meant to indicate how deeply it should be seated in the case. Without a cannelure, you have to rely on neck tension to hold the bullet, and have no way to visually identify a bullet that's seated too far forward.
An aerodynamically improved V-max? Hornady pushes the aerodynamics on this line.
A Barnes designation for a bullet with grooves in the rear, composed of a copper/zinc alloy which is harder than lead and is intended for deep penetration. These bullets are probably a little bit closer to armor piercing than your common bullet, but probably less so than semi-armor-piercing projectiles, such as the mild-steel SS109. On a side note, this is available as a 45gr 224 caliber bullet, and is somewhat tempting for the PS90...
A Sierra implementation of polymer tip.
A Spitzer bullet is, simply, a pointed bullet. In contrast to round-nose designs such as the rounds commonly used for 45ACP and 30 Carbine, a pointed bullet possesses greater aerodynamics than a round-nosed bullet.
A TNT bullet is a Speer variant of hollow point. They profess, through thin jackets, internal fluting, and a soft lead core, that their bullets fragment exceptionally well when they hit a target.
A Hornady designation for polymer tipped projectiles.