A Small Talk on Side Armor Plates
Ahh, side plates. A subject of mild contention amongst wearers of rifle rated armor systems, and one I feel deserves at least a quick overview as it isn't touched on frequently. Those little plates, typically 6"x6" or 6"x8", are often not considered in a broad context. Most people are on two sides of the matter - those that like to "turtle suit" to have as much armor coverage as possible at all times, and those that want the absolute minimum solution at all times to minimize weight and improve ergonomics.
Both sides have understandable concerns and arguments, but I think there's a slightly more nuanced take to be had on the subject of side plate usage.
My opinion is largely that they're uncomfortable and add unnecessary weight in most situations. They're especially bad if you have a short distance between the tops of your hips and the area where the plates sit, like I do. Every time I try to bend to the side with side plates on the bottom of the plates smack into the top of my hips. Not fun.
There are situations however where I would possibly choose to wear side plates myself or recommend that others do so: You're in a fixed position for an extended period of time and will be there when someone is shooting at you (stationary machine gunner, static defense, etc.)You will be inside a vehicle when someone is shooting at you. Doors are one of the weakest points on an unarmored vehicle and rifle rounds obviously tear right through them. Your sides face towards the doors.You're part of a dedicated entry team and won't be moving more than ~200 yards typically. I personally believe side plate use in the above situations is perfectly justifiable and, in certain scenarios, could even be highly recommended. Outside of those however I'm of the mind that they don't offer enough of a benefit to outweigh the weight increase and loss of comfort.
If I believed I was entering a situation outside the above scenarios where I feel side plate usage is still warranted I'd likely only wear UHMWPE, or poly side plates. While typically on the thicker side and not offering protection against M855 or similar projectiles a 6"x6" UHMWPE plate generally only weighs about a pound, making it two pounds total for a set. That is significantly lighter than all but the very top end ceramic plate solutions.