Steve Jackson Games Forums [Cutting-Edge Armor Design] Real World SCA-legal Armour and Ballistics Armour
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02-07-2018, 10:32 AM   #2
mlangsdorf

Join Date: Aug 2004
Location: Austin, TX
Re: [Cutting-Edge Armor Design] Real World SCA-legal Armour and Ballistics Armour

Quote:
 Originally Posted by Icelander Going a little more modern, how would we stat a full suit (well, back, breast and sides of torso) of AR500 Armor Lightweight Level III+ Body Armor, as well as whatever plate carrier is necessary for it?
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.

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.

You can do the same math for the 10x14", soft body plate but I'd just treat it as improved kevlar.

So all that works out to:

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

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.

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.
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02-07-2018, 11:10 AM   #3
Icelander

Join Date: Mar 2006
Location: Iceland*
Re: [Cutting-Edge Armor Design] Real World SCA-legal Armour and Ballistics Armour

Quote:
 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.

Quote:
 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.

Quote:
 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.

Quote:
 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.

Quote:
 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.
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Last edited by Icelander; 02-07-2018 at 11:14 AM.

02-07-2018, 12:45 PM   #4
mlangsdorf

Join Date: Aug 2004
Location: Austin, TX
Re: [Cutting-Edge Armor Design] Real World SCA-legal Armour and Ballistics Armour

Quote:
 Originally Posted by Icelander 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.
Right. DR 25 for 5.5 lbs at \$110 for a solid plate works out to a CM of \$20.

Cost = Weight x CM x CC.
CM = Cost / (Weight x CC). CC is 1 for solid, so \$110/5.5 = \$20.

Weight = SA x WM x CW x DR.
WM = Weight / (SA x CW x DR). CW is 1 for solid, and a 10x12" is 5/6 sqft, so 5.5 / (5/6 * 25) goes to 6 * 5.5 / 5 / 25 goes to 6.6 / 25 or 0.264. I'd originally calculated from DR 23 and got something closer to 0.3.

As far as working metals with absurdly high Brinell numbers, I assume you would work the metal while it's a lot softer and then case-harden the final form. You can (and people traditionally did) case-harden fire arm components, because you want to do the precision machining on low carbon alloys but have high carbon alloys for wear resistance in the final gun. If you can case-harden a revolver frame, you can case-harden a breastplate (though I am not a metallurgist and have only the vaguest idea of how you would do it).

I also suspect that armor like this is one of those things that is really expensive to buy one-off, but only moderately expensive to buy in lots of 100+. What your cartel would want to do is make a prototype or three out of low carbon steel, come up with a fake movie production company or similar cover story, and then have the cover company solicit bids for 100+ copies of the suit made from the proper materials. The companies who already have equipment to make metal in weird shapes and at high hardness levels will get back to you with a hopefully cost-effective solution.

Of course, if you can't afford 100 suits, you may be in a situation where can't afford to buy 10 suits, either, because you have to hand-make each one at great expense.
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 02-07-2018, 12:47 PM #5 Anthony   Join Date: Feb 2005 Location: Berkeley, CA Re: [Cutting-Edge Armor Design] Real World SCA-legal Armour and Ballistics Armour The other alternative is to just add cosmetics to bog-standard ballistic plates. __________________ My GURPS site and Blog.
02-07-2018, 01:03 PM   #6
Icelander

Join Date: Mar 2006
Location: Iceland*
Re: [Cutting-Edge Armor Design] Real World SCA-legal Armour and Ballistics Armour

Quote:
 Originally Posted by Anthony The other alternative is to just add cosmetics to bog-standard ballistic plates.
Well, my original thought is effectively 'soft ballistic armour + high hardened steel sold as cheaper alternatives to ceramic ballistic plates', with SCA-legal steel armour being added to that, as, yes, more of less cosmetic accessories, with a 'gorget', pauldrons and limb armour in, say, 16 gauge steel that was fairly easy to work giving DR 3-5, depending on exact steel and the skill of the smith.

For example, this set comes in stainless steel or mild, cold-rolled steel. I'd give it either DR 4 or DR 5, depending on whether I felt it was better or worse than RHA. Having been modelled on historical armour might let it rate DR 5, for appropriately protective shape.

Maybe add some more soft steel plates in a brigantine cuirass that has the actual hardened steel as a centerpiece, to get the right look, give knife protection and prevent injury when meth-crazy 'Knights' inevitably start sword fighting at their 'business meetings'. Total cost, around \$3,000, depending on how expensive it is to get something that looks like a gambeson made out of kevlar (and possibly some cloth covering).

This kind of get-up would be kind of a minimal bar in looking knightly for those who wanted to play at being inner circle, around the crazy leader and his most cultist followers.
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Last edited by Icelander; 02-07-2018 at 01:14 PM.

02-07-2018, 01:46 PM   #7
Icelander

Join Date: Mar 2006
Location: Iceland*
Re: [Cutting-Edge Armor Design] Real World SCA-legal Armour and Ballistics Armour

Quote:
 Originally Posted by mlangsdorf Right. DR 25 for 5.5 lbs at \$110 for a solid plate works out to a CM of \$20. Cost = Weight x CM x CC. CM = Cost / (Weight x CC). CC is 1 for solid, so \$110/5.5 = \$20. Weight = SA x WM x CW x DR. WM = Weight / (SA x CW x DR). CW is 1 for solid, and a 10x12" is 5/6 sqft, so 5.5 / (5/6 * 25) goes to 6 * 5.5 / 5 / 25 goes to 6.6 / 25 or 0.264. I'd originally calculated from DR 23 and got something closer to 0.3.
Apparently, Ultra-Strength Steel in Pyramid is meant to represent materials that are genuinely cutting-edge in vehicle armour applications.

Unless I can confirm that the cheaper very high hardness Abrasion Resistant steels are equivalent in protective value against all threats as vehicle armours made from triple-hardened steels or nano-metric/nano-crystaline steels, I'd be loath to give equivalent or better stats to AR500.

We know the DR against piercing damage, but isn't it possible that such very high hardness steels are actually more protective against typical fast-moving, light penetrators made from, generally, softer materials, than they are against some other types of damage?

In other words, maybe a 5.5 lbs., almost 1 square feet, NIJ Level III certified plate of AR500 should have DR 25 against piercing (and possibly cutting), but only modestly better DR than an equivalent thickness and/or weight of TL6 'Hard Steel' would have against other threats.

I mean, should it resist collisions (cr), cutting torches (burn), HEAT (cr ex) or explosively-formed penetrators (imp) any better than the kind of steel used for TL7 and TL8 APC or tank armour?

Quote:
 Originally Posted by mlangsdorf As far as working metals with absurdly high Brinell numbers, I assume you would work the metal while it's a lot softer and then case-harden the final form. You can (and people traditionally did) case-harden fire arm components, because you want to do the precision machining on low carbon alloys but have high carbon alloys for wear resistance in the final gun. If you can case-harden a revolver frame, you can case-harden a breastplate (though I am not a metallurgist and have only the vaguest idea of how you would do it).
As I understand it, making hardened alloys of high-carbon steel, chrome-moly and manganese is something only very specialised suppliers do.

Machinists, smiths, speciality stores or custom workshops buy high hardness Abrasion Resistant steels, they don't make the alloys themselves. And it looks like you can only buy AR500 in sheets, targets, trauma plates, i.e. what 'Cutting-Edge Armor Design' calls Solid.

Maybe you can get some other kind of very hard steel made in specific shapes, but I suspect it would be very expensive to do so for a few suits of armour. Maybe if you were looking to buy enough of each part to make a line of wear-resistant power tools or Caterpillar attachments.

Quote:
 Originally Posted by mlangsdorf I also suspect that armor like this is one of those things that is really expensive to buy one-off, but only moderately expensive to buy in lots of 100+. What your cartel would want to do is make a prototype or three out of low carbon steel, come up with a fake movie production company or similar cover story, and then have the cover company solicit bids for 100+ copies of the suit made from the proper materials. The companies who already have equipment to make metal in weird shapes and at high hardness levels will get back to you with a hopefully cost-effective solution.
I think you are right here.

Which is why I think that only Raul Vargas, the undisputed leader of this surviving subgroup of the Knight Templar Cartel, has any chance to have a custom-made plate harness out of a steel hard and tough enough to have meaningful ballistic resistance.

The rest should find other methods of sort of looking like Knights, while being protected at least as well as if they were wearing tactical vests with trauma plates.

Quote:
 Originally Posted by mlangsdorf Of course, if you can't afford 100 suits, you may be in a situation where can't afford to buy 10 suits, either, because you have to hand-make each one at great expense.
Well, there aren't 100 trusted inner circle lieutenants, bodyguards or leaders of soldiers, anyway, in this splinter faction of the original cartel.

There's probably about a dozen men close enough to the leader and crazy enough to buy into his 'Knight Templar' propaganda to the extent that they attend banquets wearing faux-medieval armour. Say about twice that who'll pay it lip service and attend wearing more-or-less medieval movie-setting appropriate clothing, but not functional armour.

And maybe thirty or forty loco gunmen who mix this sort of Ren Faire aesthetic with their norteño or narcocultura aesthetic in the hope of currying favour with the Jefe (or because they are crazy and have been with the Knight Templars for five years, which for some of them might have been since they were ten years old, so some of them probably swallow the entire 'Knights' bit whole).

Drug baron Raul Vargas is not going to finance full plate armour for all these men. He needs his money! For operating costs, for bribery and gifts to important people in allied Drug-Trade Organisations (DTOs) to increase his power, for investments in a huge real estate development that he hopes is going to make him a legitimate billionaire one day, etc. Not to mention absolutely ridiculous amounts of cocaine, methamphetamine, top-shelf booze and other luxury goods for personal use.

Vargas might be willing to pay for cool knight armour for his bodyguards and those of his lieutenants who take the 'Knight Templars' bit seriously, but that's always going to be less than twenty suits. But he is absolutely going to have a personal full plate harness that incorporates as much actual ballistic protection as possible, because while he is crazy, he is crazy like a fox. He likes stuff that skirts the line of 'Awesome but Impractical', but is actually somewhat effective, if much more expensive than a less cool way to do it.
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Last edited by Icelander; 02-07-2018 at 01:55 PM.

02-09-2018, 03:52 AM   #9
Rupert

Join Date: Aug 2004
Location: Wellington, NZ
Re: [Cutting-Edge Armor Design] Real World SCA-legal Armour and Ballistics Armour

Quote:
 Originally Posted by Icelander 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.
You form the steel while it's red hot, and thus somewhat soft, and then cool it (hopefully in the correct way, otherwise it'll give much less protection than you expect).

Quote:
 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).
If you're willing to go to the rouble of serious heat-treating there almost certainly are, but forming then treating it will be damned expensive.
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Rupert Boleyn

"A pessimist is an optimist with a sense of history."

 02-07-2018, 11:38 AM #10 mlangsdorf   Join Date: Aug 2004 Location: Austin, TX Re: [Cutting-Edge Armor Design] Real World SCA-legal Armour and Ballistics Armour Ballistic black knight harness, take 2: DR 20 polyurea coated light steel armor solid skullcap: 1.4 sqft, WM 0.3, CM 40, CW 1, CC 1, DR 20: 8.4 lbs, \$340 DR 5 transparent laminated polycarbonate eyeslits: 0.1 sqft, WM 0.25, CM 50, CW 0.8, CC 5, DR 5: 0.1 lbs, \$25 DR 6 hard steel plate neck and face: 1.3 sqft, WM 0.5, CM 3.5, CW 0.8, CC 5, DR 6: 3.15 lbs, \$55 DR 20 polyurea coated light steel armor plate over the vitals: 1 sqft, WM 0.3, CM 40, CW 0.8, CC 5, DR 20: 4.8 lbs, \$960. DR 12F/6B hard steel plate torso other than vitals: 6 sqft, WM 0.5, CM 3.5, CW 0.8, CC 5, DR 9 (average for calculating cost/weight): 21.6 lbs, \$380 DR 8F/4B hard steel plate arms, legs: 10.5 sqft, WM 0.5, CM 3.5, CW 0.8, CC 5, DR 6 (average for calculating cost/weight): 28.35 lbs, \$500 DR 4 hard steel plate hands, feets: 1.4 sqft, WM 0.5, CM 3.5, CW 0.8, CC 5, DR 4: 2.25 lbs, \$40 DR6 improved kevlar undersuit: 21.35 sqft, WM 0.08, CM 120, CW 1, CC 1, DR 6: 10.25 lbs, \$1230 Total is 78.9 lbs, \$3530. A little over weight and budget, but the protection is good. The important parts are completely resistant to 7.62mm rounds and the arms and legs are nearly resistant to 5.56mm rounds from the front. You can stand in a fire for 45 seconds without worrying about burning or heat. The biggest weak point is the eye slits at DR 5. against bullets and axes (-4 DR against other damage types) DR 26 over the skull and vitals, DR 21 over the rest of the front torso, DR 15 over the face and neck, DR 14 over the arms and legs from the front, DR 10 for the hands and feet and back of the limbs, DR 12 for the back torso. An obvious way to save weight would be to replace the steel on the limbs with aluminum, but at 3.5x the cost of hard steel, it wasn't feasible for the \$3000 budget. Dropping the limb armor down to DR4, front and back, would also save about 10 lbs and DR 10 is sufficient to stop 9mm bullets. At the upper level of protection, titanium composite is 40% the weight of hard steel but 30x as expensive. Using titanium composite for the limbs would drop the weigh by 17 lbs, but would raise the cost by over \$14000, so it's not really feasible. __________________ Read my GURPS blog: http://noschoolgrognard.blogspot.com

 Tags cutting-edge armor design, hema, jade serenity, pyramid #3/85, sca

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