I get asked this question ALOT... Mostly because of someone else selling "Barrel" plates at a show, but sometimes because of some YouTube videos that seem really scary...
Here's the breakdown of the video... someone takes a Multi-Curve plate and uses it as a target with balloons all around it to demonstrate spall, and ALL the balloons burst... scary right? there are a few flaws with this concept though. In REAL LIFE we are not simply holding a plate in front of ourselves, we have them securely fastened in a plate carrier, which in itself will change the trajectory of spall as well as mute the effect. We are also not simply standing in front of a firing squad, REAL LIFE has angles and differing velocity all factors which change the impact of spall. EVERY metal plate will have spall or fragmenting of the round, the curve of the plate does not change this, and it does not direct the spall in real life conditions.
So why DO I carry Combat Curve Plates? Simple... I wear my plates!
What I have found is that plates with a Combat Curve wear lighter and are many times more functional than barrel plates. The top curve of the front plate allows it to sit flatter against your chest, which shifts the dynamics of your plate carrier. Your carrier's job is to hold your gear against your body, and if your plate doesn't conform to your body you have to over tighten the waist to keep your plates from bouncing around. Overtightening then cause your movement to be restricted, specifically it restricts your breathing. If you have spent any time around me I'm sure you have heard me tell someone that the best way to adjust your carrier is to put it on and tighten it down, then RUN up at least one flight of stairs, now take a deep breath, if you can't get a full breath your carrier is too tight... REPEAT THIS until you find that sweet spot where your plates don't move, and you can get a full breath... this could take a few times and you will likely curse me the entire time, trust me IT'S WORTH IT!!!
The bottom line is that if someone is shooting at you... you have to assume that they are trying to kill you and that they may shoot again. (Seems logical right... keep following me) This means you need to manuver, you need to find cover and get to it quickly, you need to run, you need to be able to use your weapon. YOU CAN DO NONE OF THIS IF YOU CAN NOT BREATH. That is why I sell and personally wear Combat Curve Plates.
If you are concerned about spalling, which is a real thing that has a ton of mis-information surrounding it, we carry plates with a buildup coat designed specifically for absorbing spall into the plate.
There seems to be confusion surrounding SAPI/ESAPI, shooters cut, swimmers cut... so many things and the acronyms are applied incorrectly all the time!
Military SAPI/ESAPI Sizing:
All of our Steel plates are Commercial Sizing with SAPI shape
Everything else Swimmers cut, Shooters cut etc refers to the shape of the plate SAPI shape is standard.
Trauma Pads are designed to help reduce the impact to your body.
Unfortunatly Body Armor does not make us invincible, the impact of a round hitting your plates could break bones and cause internal bleeding just due to the sheer force (or more accuratly, the amount of energy that your plates need to stop). Trauma pads are designed to be another way to help disburse the impact.
Getting hit by a round can still knock you over, it can deform your plate to the point of broken ribs... long story short... it's not fun.
Here's a fun analogy...
You get puched in the somach... knocks the wind out of you right? Now, if you place a dense (perhaps Memory Foam) pillow infront of you the punch still lands and it might push you back, but it doesn't have the same impact... TRAUMA PAD... you dissipated the energy of the punch through the density of the pillow.
Trauma pads go in the same compartment as your plates (they belong closest to the body).
What Trauma Pads are not...
Technically, a Flak Jacket is Body Armor, however these "Jackets" were designed to protect the wearer from LOW Velocity projectiles... think flying debris and shell casings.
Sadly I have witnessed people selling Flak Jackets as "Bullet Proof" ... the problem lies with the velosity. Bullets by their very nature move at a high velocity. While it's true that some Flak Jackets have been demonstrated to defeat a bullet, this ability varies widely and is in direct correlation to the velocity and angle of the projectile, the distance it was fired and the weapon it was fired from.
It was claimed that the M-1951 flak jacket could stop a 90 grain 7.62×25mm Tokarev pistol round at the muzzle of the gun. However, even the Vietnam era revised flak jacket was not really designed to stop an AK-47 round (7.62×39mm) fired at close range. Nevertheless, it did a good job of stopping shell blasts, rocket fragments, and slow speed bullets fired at a moderate range.
Flak Jackets have their place and purpose HOWEVER, they are not "bullet proof"