In designing a near future military, it becomes vital to determine what is currently used, to gauge where the future is (presumably better, one would hope!). TL9 guns are generally assumed to be similar to TL8 weapons, differing with slightly increased damage due to improved powders, and lighter caseless ammunition (which has its own host of problems, but reduces the odds of FTE jams by having nothing to eject).
In the 1990s, a soldier or marine might wear the following
Fragmentation Vest w/ Plates. DR 5/2*, 9lbs, $3500 plus DR 25, 16 lbs, $350. Total DR 30/27, 25lbs $700
Frag Helmet DR5, 3 lbs $125
Boots, Jungle DR 3/2, 3lbs, $75
In 2010, a soldier or marine might wear the following
Assault Vest w/ Plates. DR 12/5*, 8 lbs, $900, plus DR 23, $600 OR DR 25, 8lb, $1000, Total DR
Ballistic Helmet, DR 12, 3lbs $250
Tactical Goggles, Nictitating Membrane 5 (DR 5 to the eyes) $100, Negligible Weight.
(OPTIONAL) DAP, DR 8/2*, 4 lbs, $100, protects shoulder and upper arm
Boots DR 2*, 3lbs $80, stealth +1 due to similarities in the modern tactical boot to running shoes.
The Trauma Plates listed in the box are SAPI plates, 4 lb ceramic plates rated to NIJ III protection (will stop up to 7.62x51 NATO ball ammo, 7d pi, 24.5 damage average). Modern plates may use ESAPI plates (rated to stop 30-06 AP, 7d+1 (2) pi-, 25.5 damage average for armor pen, 12 damage average to flesh), but aren't listed in GURPS. As the damage doesn't really change, a better way to treat them would be to add the Hardened modifier. Using stats available online, ESAPI plates are 5.5lbs, and are able to absorb the impact of basic armor piercing ammo (Hardened 1).
Not listed in GURPS are lightweight Plate Carriers with no inherent DR (but also nearly no inherent weight). Using stats available for plate carriers on the market, a plate carrier like the Scaleable Plate Carrier might be
1.5 lbs, possibly DR 1 (they're usually pretty sturdy fabric, but usually nothing bullet resistant).
From this, we get that the modern established military equips their troops with DR12 to the skull (pistol/frag rated), DR 23-35 to the torso depending on mission, and a nice set of sturdy boots. Gloves, deltoid and axiliary protection, and eye protection may be optional. Ballistic limb protection exists, but is very rarely used outside of guards and exposed turret gunners due to weight and cost.
So where do we go from here?
The first, most obvious place is Reflex clothing (DR 12/4*, weight 3lb, $450 for jacket (torso+arms) and 2.8 lbs, $280 for pants (legs+groin). This protects the vast majority of the soldier from non armor piercing pistol fire and fragmentation. Reflex gloves add 6/2*, neg weight, and $30 to the hands.
Total weight of giving the body some measure of damage resistance from the neck down is $760, 5.8 lbs with the gloves. This option may not always be taken.
An alternative full-body armor is available in:
Reflex TacSuit, 20/10* DR, 15 lbs, C/12hr power, $3000. Covers the entire body from the neck down, and provides climate control if you put on a sealed helmet or mask.
Reflex Vacc Suit, 20/10* DR, 30 lbs, 2C/24 hr power, $12,000. As above, but vacc rated. Gives climate control, pressure support (10 atm), radiation protection PF 2, and vacuum support (with proper helmet), plus biomed sensors
Skinsuits may be issued by militaries facing hostile environments such as other planets or the void of space, as they give DR 2* and provide vacuum support and significant climate control. Skintight space undies.
On top of this might go a
Reflex Tactical Vest (18/7* DR, 9lbs, $900, plus 34 DR, 9lbs, $600 plates), total of 52/41 DR, 18lbs,
Light Clamshell, 30 DR, 12lbs, $600
Heavy Clamshell, 45 DR, 18 lbs, $900.
The reflex tac vest might be worn as standalone primary armor, with no armored BDUs. Light or heavy clamshell atop reflex BDUs gives troops good survivability, and still pretty cheap and light.
Limb armor is taken care of by reflex BDUs, but heavier armor might be desired. Based on the Light and Heavy Clamshell, Ultralight would offer 15 DR, 6lbs, and $300 for the torso. Using the armor creation rules from Ultra-Tech or Low-Tech you can make other armors from the torso armor.
To adapt torso armors into a full suit for use with the Ultratech rules, multiply cost and weight by 4.
DAP, 20% cost and weight of torso armor
Arms, 50% cost and weight of torso armor
Legs, 100% cost and weight of torso armor
Full Suit (neck down, not including hands and feet), 255% cost and weight of torso armor
An average troop might add Ultralight or even Light clamshell DAP to their kit, or just have whole body coverage of clamshell armor, while special operations might layer it over a tacsuit for extreme damage resistance.
Special cases may even warrant the following
Combat Hardsuit, 50/30 DR (torso/everywhere else), 30 lbs, $10,000. Worn with a space rated helmet, gives radiation PF 2, biomed sensors, waste relief system, and climate control. Not vacuum/pressure rated, but can operate in other kinds of harsh environments
Space Armor, 50/30 DR (torso/everywhere else), 45 lb, $20,000. Worn with a space rated helmet, gives radiation PF 10, Pressure support (10 atm), climate control, and biomed sensors
There are several options when selecting helmets, depending on environment.
Troops expecting to fight only in planetary environments may use the following.
Light Infantry Helmet, 18 DR, 3 lbs, $250 protects skull
Visor, 15 DR, 3 lbs, $100 (Protects eyes/face)
Armored Shades, 10 DR, 0.1 lb, $100
Air Mask, 10 DR, 1 lb, protects eyes/face, $100. Requires air tank
Filter Mask, 10 DR, 3 lb, protects eyes/face, $100. Filters breathable but contaminated environment.
All may add $50 for a HUD, or integrate any passive visual sensors
Combat Infantry Helmet, 18/12 DR (18 skull, 12 eyes/face), 5 lb, $2000, B/12 hr. Provides Sealed when worn with a combat hardsuit or tacsuit. Includes GPS, Hearing protection, small radio, infrared visor w/ HUD, and filter masks.
Troops that may be exposed to vacuum may use the following
Visored Space Helmet, 20/15 DR (20 skull, 15 eyes/face), $2000, 4 lbs. Incorporates small radio, IR visor, and hearing protection. Seals and provides vacuum support.
Space Combat Helmet, 40/30 DR (40 Skull, 30 eyes/face), $3000, 7 lbs. Incorporates small radio, IR visor, and hearing protection. Seals and provides vacuum support.
Any suits without integrated boots receive TL9 combat boots
Assault Boots, 12/6 DR (underside/sides), 3lb, $150. Add +4 to hiking skill.
What do we get from all this?
Future combatants have more variation in armor for different applications. Heavy gunners, turret gunners, special forces, and so forth.
On average, a typical frontline combat troop will have 40+ torso DR, between 0 and 30 limb DR, 18+ skull DR, and at least heavy armored eye protection with a HUD to run assorted tactical programs. Armor weight, kept to a minimum, is lower than that of a modern TL8 combat load. However, taking advantage of the substantially more extensive protection possible may push the weight above that of a current fighter. However, ultratech suits like the skinsuit, tacsuit, combat armor, and space armor allow substantial amounts of gear to be done without, such as warm/cold weather gear and sleeping bags, and lighter/more compact foodstuffs, weapons, and ammunition. Due to easy accessibility, combat in differing environments and conditions.
Future combat is likely to involve major injuries to limbs, death of a thousand cuts with penetrating damage doing a few points of blunt trauma at a time through torso armor (or, knockout), or a showstopper with a lucky/skilled headshot. Armor piercing ammunition is all but mandatory between major armor issuing powers. The listed ultratech weapons do 6d or 7d for the average infantry small arms (21 and 24.5 damage, respectively), meaning 40-50 DR can soak an armor piercing shot without being Hardened.