Some years ago, I was trying to run a Star Wars game and was looking to see what kinds of armor the Imperial stormtroopers would wear. I had two goals in mind for this: enable the stormtroopers to be effective when played by PCs, while at the same time enabling them to go down with hits from blasters when opposing the PCs. I'd ran a Star Wars game years before, and learned the hard way that giving stormtroopers with HT 12 the TL11 Combat Hardsuit from Ultra-Tech led them to remain active after taking multiple hits, which did not reflect the movies where they would go down after being shot with a heavy or even sporting pistol.
With this in mind, I turned to the Clamshell armors. Running the numbers, using the damages and armor divisors of Ultra-Tech's blasters, I saw that Light Clamshell performed much like the stormtrooper armor on the screen: it lowered the damage from pistols from "certain death" to "down for the count", while nearly useless against rifles. Heavy Clamshell protected nicely against blaster rifles, turning certain death to "needs medical attention". Okay, these could suffice for stormtroopers; the bulk of the Stormtrooper Corps would wear armor derived from Light Clamshell, while bounty hunters and more elite units like the 501st would wear Heavy Clamshell. I also derived a "medium clamshell" halfway in protection, weight, and price between light and heavy, to give players even more variety. However, the Clamshells on page 176 of Ultra-Tech only gave me stats for the torso, not the whole body.
Thankfully, right about this time, Low-Tech was released, with its wonderful armor rules. So, I decided to reverse engineer the Clamshells into something that would help cover the entire body.
When dealing with armor, there are two ways to take the "torso" statement in Ultra-Tech when comparing it to the armor design system in Low-Tech. The first is to take it at face value; the "torso" in Ultra-Tech (and the Basic Set) indicates the entire torso: chest and abdomen. The second is to treat the the Basic Set/Ultra-Tech "torso" location as what Low-Tech calls the "chest" area. Confusing the issue is the statement in Ultra-Tech that the clamshell is described as a "cuirass", which in Low-Tech is chest-only. Obviously, the two methods are mutually exclusive; the lists below represent both methods:
UT's "Torso" is LT's "Chest"
Light Clamshell:
Cuirass: $600, 12 lbs.
Fauld: $200, 4 lbs.
Sleeves: $400, 8 lbs.
Gauntlets: $80, 1.6 lbs.
Leggings: $800, 16 lbs.
Boots: $80, 1.6 lbs.
Full Set: $2,080, 41.6 lbs.
Helmet: $240, 4.8 lbs.
Medium Clamshell:
Cuirass: $750, 15 lbs.
Fauld: $250, 5 lbs.
Sleeves: $500, 10 lbs.
Gauntlets: $100, 2 lbs.
Leggings: $1,000, 20 lbs.
Boots: $100, 2 lbs.
Full Set: $2,700, 54 lbs.
Helmet: $360, 6 lbs.
Heavy Clamshell:
Cuirass: $900, 18 lbs.
Fauld: $300, 6 lbs.
Sleeves: $600, 12 lbs.
Gauntlets: $120, 2.4 lbs.
Leggings: $1,200, 24 lbs.
Boots: $120, 2.4 lbs.
Full Set: $3,120, 62.4 lbs.
Helmet: $360, 7.2 lbs.
UT's "Torso" is LT's "Torso"
Light Clamshell:
Cuirass: $450, 9 lbs.
Fauld: $150, 3 lbs.
Sleeves: $300, 6 lbs.
Gauntlets: $60, 1.2 lbs.
Leggings: $600, 12 lbs.
Boots: $60, 1.2 lbs.
Full Set: $1,620, 32.4 lbs.
Helmet: $180, 3.6 lbs.
Medium Clamshell:
Cuirass: $562.50, 11.25 lbs.
Fauld: $187.50, 3.75 lbs.
Sleeves: $375, 7.5 lbs.
Gauntlets: $75, 1.5 lbs.
Leggings: $750, 15 lbs.
Boots: $75, 1.5 lbs.
Full Set: $2,025, 40.5 lbs.
Helmet: $225, 4.5 lbs.
Heavy Clamshell:
Cuirass: $675, 13.5 lbs.
Fauld: $225, 4.5 lbs.
Sleeves: $450, 9 lbs.
Gauntlets: $90, 1.8 lbs.
Leggings: $900, 18 lbs.
Boots: $90, 1.8 lbs.
Full Set: $2,430, 48.6 lbs.
Helmet: $270, 5.4 lbs.
For reference, the Combat Hardsuit weighs 30 pounds, and has 11% to 25% more DR than Heavy Clamshell over the chest for a given TL.
What I discovered was that the full suits of clamshell armor weighed much more than the combat hardsuits, although undoubtedly cheaper at about 1/5 to 1/3 of the price.
Let's take an ST 10 Stormtrooper, fresh from training, with BL 20 lbs. No encumbrance is up to 20 lbs, light encumbrance is up to 40 pounds, and medium encumbrance is up to 60 pounds. Using the first set, the TL11 stormtrooper is greatly encumbered by his armor, as he's wearing 46.4 pounds bumping him up into medium encumbrance; the second set he's still at light encumbrance at 36 pounds. That's before accounting for his E-11 blaster carbine, an additional 5.6 pounds; this puts both into medium encumbrance (which in turn would explain their slow running speeds on the Death Star....).
How I determined that the light clamshell would suffice against blaster pistols and the heavy against blaster rifles came from comparing the blaster stats on p. 123 of Ultra-Tech against the DR values listed for the Light Clamshell and Heavy Clamshell armors of the same TL. Blasters are TL11, so it makes sense to treat the armor as TL11 as well.
A blaster pistol does 3d (5) burn sur, a range of 3 to 18 with a median of 10.5; a TL11 light clamshell has DR 60, but the Armor Divisor (5) reduces that to an effective DR 12. A blaster carbine does 5d (5) burn sur, a range of 5 to 30 with a median value of 17.5; heavy clamshell armor has DR 90, which the AR (5) reduces to an effective 18; a standard blaster pistol is rendered ineffective against heavy clamshell. A heavy blaster pistol like Han's DL-44, doing 4d (5) burn sur, a range of 4 to 24 with a median of 14, may be able to penetrate the heavy clamshell. Against a TL11 combat hardsuit, with DR 100 on the torso and 60 elsewhere, even heavy pistols are practically useless, while the carbines are capable of punching through it roughly 40% of the time. If Imperial stormtroopers wore anything heavier than light clamshell, Leia's sporting blaster (a blaster pistol with Fine (Accurate), giving a bonus to the weapon's Acc score but not affecting the damage) would not have knocked out or killed the one she shot at the start of the original movie.
It's not always obvious, but sometimes the numbers in Ultra-Tech do work! :)