[Icelander]

Originally Posted by mlangsdorf

The 10x12" plate weighs 5.5 lbs and protects against .308 rounds, but not 5.56 AP rounds, so call it DR 23. Simple math puts 1 sqft of the stuff at DR 23 weighing 6.6 lbs.

By NIJ standards, Level III armour needs to be DR 25 to be actually rated to stop 7.62x51mm NATO from full-length barrels. Average damage is 24.5, after all.

Level III+ is not a recognised NIJ standard, but it is used by many manufacturers. Assuming that the tests were performed correctly, the highest damage round mentioned puts it at DR 29-30, by GURPS standards, stopping 7.62x51mm AP rounds (not APHC, and old-school AP puts it at 7d(2)*0.6 = 24.5(2)*0.6 = 49*0.6 = 29.4).

Note that some AR500 armours were recalled for failing to meet advertised standards, but the currently sold versions allegedly meet these standards, as they just had to go through independent testing. That said, I wouldn't mind DRs that were 1-2 points lower than they ought to be, on account of this being cheap and dirty ballistic armour from a disreputable manufacturer.

Originally Posted by mlangsdorf

Armor weight is SA x WM x CW x DR. CW of a solid plate is 1, weight is 6.6 lbs, DR is 23, and SA is 1 sqft. A little algebra and the WM of the stuff is 0.286 - call it 0.3 for simplicity. That's better than TL7 titanium alloy or TL8 ultra-strength steel, but not as good as TL8 titanium or polymer composite.

You can do similar math to get the CM, which works out to $20 - which is probably too low. I'm going to arbitrarily double it to account for the difference between a GURPS TL8 $ and 2017 USD.

It's DR 23, and 0.21" thick, so it has DR 109/in. Max DR on a human is 27 for a 1/4" plate.

I'm pretty sure that with a hardness of BHN 460-544, this abrasion resistant 'AR500' steel is not going to be easily shaped into anything other than Solid plates or, at most, very gently curving ones.

For the purposes of the design system, it looks like most of the commercially available AR500 steel armour is effectively Trauma Plates, which are usually Solid, i.e. Ceramics (which can only be Solid).

I actually don't know if there are steel alloys with DR this high available today which can be manufactured as articulated plate armour, as opposed to just plate inserts of high DR ballistic protection that you use to protect the most important 40% to 60% of your Torso hit location (using up to four plates, front chest, back and two sides).

On the other hand, I found real examples of 3/8" thick trauma plates made from this steel, so it looks like the 1/4" limit does not necessarily hold true for Solid plates, as opposed to articulated-armour Plate construction. I think ceramic trauma plates can be more than 1/4" too, so it has precedent.

Note that some adventurer useful gear costs the same or is even cheaper than when GURPS 4e was published. As such, I use a generic scale of GURPS $ = real-world $, but prices for individual goods may change.

I haven't made up my mind whether or not body armour prices generated by the 'Cutting-Edge Armor Design' match any particular year. In any case, let's not use any modifier to Cost unless we find that there is a need to apply them generically to all materials or specifically to types of materials we have discovered to have changed in price from the reference prices used in GURPS.

Originally Posted by mlangsdorf

Polyurea coated lightweight steel armor: WM 0.3, CM $40, DR/in 109, Max DR 27, Notes -, Construction R/S.

We've got price information on Solid trauma plates made from this material. Slightly less than 1 square foot with DR 23-30, depending on the validity of the testing, seems to cost $100-$200, depending on specifics.

Originally Posted by mlangsdorf

A suit of the polyurea coated lightweight steel plate, worn over a suit of the AR500 Hybrid ballistic weave:
Steel armor: LSA 21.35, WM 0.3, CM $40, CW 0.8, CC 5, DR 24: 123 lbs, $24600
Ballistic weave: LSA 21.35, WM 0.08, CM $120, CW 1, CC 1, DR 10: 17 lbs, $2050.

Are you aware of any real world full-body suits made of Kevlar, aramid weaves or similar materials?

Would not wearing the same thickness as about Level II or Level IIA concealable vests over the entire body, limbs, joints and everything, not cause some flexibility issues? To say nothing of heat issues?

I'm prepared to apply such if appropriate.

Originally Posted by mlangsdorf

Since armor weight and cost is linear with DR, we can drop the steel armor to DR 8, reducing the weight to 41 lbs, the cost to $8200, and count on the ballistic weave to catch stragglers. The combination is just over 1/4" thick, weighs 58 lbs, costs $10250, and will stop 5.56mm rounds and significantly slow down .308 rounds.

Unfortunately, you're already breaking the Lord of Darkness cost point. Let me come back on optimizing this stuff - I have some ideas.

Jay-zus!

Do you believe that you could get this built in the real world for anything close to this price point? Are there even companies which would make a full-body ballistic suit, as opposed to protecting the important parts, as almost every commercial product I can find does?

I had imagined that most of the limbs, as well parts of the lower abdomen and maybe basically anything which needs to be shaped to the body, as opposed to utilising a gently curved Solid trauma plate, would be made from traditional steel, by some company marketing to re-enactors, because the extremely high DR hardened steel would be too hard to work into any kind of actual armour shape.