Tag Archives: body armor

Giant OTV/IOTV Weight Chart

I do like playing around with weight accounting, and I do like tinkering. The following charts were pulled from a US Army service manual1 on the Interceptor Body Armor System. They’re remarkably annoying to find online in detail, and details are important. Especially if you want to play with your own configurations. So in the interest of knowledge and thoroughness, the charts are reproduced here. All weights below are in pounds.

First, the Outer Tactical Vest. This is the vest you see in early Operation Iraqi Freedom Photos.

Base vest6.646.957.668.389.519.8410.8111.79
Throat Protector Assy.
Yoke and Collar Assy.0.900.951.
Groin Protector Assy.0.700.700.700.850.850.850.850.85
ESAPI Plates (pair)7.609.5010.9012.5014.2014.2014.2014.20
ESBI Plate Carriers (pair)2.802.802.802.802.802.802.802.80
ESBI Plates (pair)
Total System Weight29.4931.7533.9136.4839.41>39.8440.9141.99

Next the Improved Outer Tactical Vest, Gen I. This reconfigured the armor a bit and added a quick release system for easier medic access to a wounded soldier, among other features. Note also the addition of some long sizes, and that the Axillary protection system (the A in DAPS) and the carriers for the ESBI side plates are now integrated into the IOTV base vest.

Base Vest9.019.339.8610.6010.9711.2411.9812.5113.5215.8016.17
Front Yoke/Collar Assy.0.560.560.560.560.560.560.560.560.560.560.56
Rear Yoke/Collar Assy.0.800.830.880.880.910.910.960.961.021.171.17
Groin Protector Assy.0.720.720.720.720.870.870.870.870.870.870.87
Lower Back Protector Assy.0.670.670.670.670.670.670.670.670.670.670.67
Deltoid Protector Assy. (pair)
ESAPI Plates (pair)7.609.5010.9010.9012.5012.5014.2014.2014.2014.2014.20
ESBI Plates (pair)
Total System Weight25.4628.7131.0931.8333.9834.2537.2437.7738.8441.2741.64

Finally, we come to the Improved Outer Tactical Vest, Gen II. This vest brought a bunch of minor improvements.

Base Vest9.619.9310.5611.3011.7211.9912.7813.3114.3216.6016.97
Front Yoke/Collar Assy.0.560.560.560.560.560.560.560.560.560.560.56
Rear Yoke/Collar Assy.0.800.830.880.880.910.910.960.961.021.171.17
Groin Protector Assy.0.720.720.720.720.870.870.870.870.870.870.87
Lower Back Protector Assy.0.670.670.670.670.670.670.670.670.670.670.67
Deltoid Protector Assy. (pair)
ESAPI Plates (pair)7.609.5010.9010.9012.5012.5014.2014.2014.2014.2014.20
ESBI Plates (pair)
Total System Weight27.0629.3131.7932.5334.7335.0038.0438.5739.6442.0742.50

That’s as far as this copy of the manual goes. Probably for the best. That’s more than enough tables for one day.

  1. TM 10-8470-208-24&P 

Ballistic Combat Shirt

Body armor. Don’t go outside the wire without it, right?

The upper thoracic cavity is where the heart and lungs are. That’s what we’re trying to protect. And hard plates like ESAPI do a good job of protecting the front and rear of the upper thoracic cavity. The sides get more difficult, because you have arms. There’s still a lot of important blood vessels, and rather complicated joints in the area above and to the sides of where plates go, regardless of whether you are wearing an armor carrier like the IOTV or a simpler plate carrier rig.

The IOTV comes with a number of accessories to protect the neck, collarbone region, shoulders, and the sides of the upper thoracic cavity. These components are the yoke and collar assembly and the Deltoid protector. These consist of an inner soft armor component, an outer cordura casing, plus attaching hardware. In size L the total weight of these accessories is 3.87 lbs.

We can contrast that with a ballistic combat shirt. This is the usual modern style of combat shirt, with heavier material for the sleeves and upper torso and lighter material for the abdomen, that’s designed for (somewhat) more comfortable wear with body armor. In the BCS, the upper chest and shoulder region contains segmented soft armor panels, providing the same ballistic protection as the aforementioned yoke and collar assembly and the deltoid protector, but the total weight of a size L Ballistic Combat Shirt is only 3.2 lbs. This looks like about half a pound of weight savings, but remember, this includes the combat shirt. A modern-style combat shirt sans armor weighs about 0.9 lbs.1 So, for system weight, we’re looking at more like 1.4ish lbs. of weight savings. Not a lot, but every little bit helps.

Weight savings isn’t the only gain here. We’re removing a lot of bulk from the shoulder area, which is a big win in terms of how much it sucks to wear. Deltoid protectors get caught on things. They make narrow doorways, crawlspaces, and vehicle hatches more annoying to move through. Less bulk means you can move through these areas faster. The bulk also makes weapon manipulation more annoying. In testing, soldiers unanimously praised the new ballistic combat shirts for being less bulky and annoying. The loss of the various straps and buckles to attach all the above components is probably also a big hit.

It’s often very difficult to reduce soldier load by reducing protection for the regular “line” infantry. Special forces guys play by different rules, but the regular grunts are usually stuck with a heavy load. Sometimes it takes some out of the box thinking to be able to make some small gains.

  1. Source here, though they don’t tell me size. Shouldn’t matter much though. “A bit less than a pound is probably a fair approximation for most modern NyCo shirts with this style of cut and a flame-resistant treatment. 

Body Armor Ratings

Body armor toughness comes in a bunch of different flavors. Over here in the US, we have a couple standards. There’s the National Institute of Justice (NIJ) standards, standards used by the US military, plus a bunch of other marketing-speak. Let’s break it down.

First, NIJ:

Level II9x19mm (124 gr. FMJ @ 1,305 fps), .357 Magnum (158 gr. JSP @ 1,430 fps)
Level IIIA.357 SIG (127 gr FMJ @ 1,470 fps), .44 Magnum (240 gr. SJHP @ 1,430 fps)
Level III6 rounds 7.62x51mm M80 (148 gr. FMJ @ 2,780 fps)
Level IV1 round 7.62x63mm (.30-06) M2 (166 gr. AP @ 2,880 fps)

NIJ ratings are commonly used for armor marketed to law enforcement and civilians. Some notes:

  • All velocities listed above are approximate, and should be understood to be +/- 30 fps.
  • Level II and IIIA are soft armor, and are understood to be reasonably multihit.
  • Level III and IV are hard plate armor.
  • Level IV is required to be able to withstand at least one round of 7.62x51mm M80 FMJ. It is not required to meet Level III multihit standards (6 shots) against M80.
  • You may notice there is no testing required against SCHV rounds (e.g. 5.56x45mm, 5.45x39mm). Level III armors may or may not stop SCHV rounds. Level IV armors are required to stop at least one SCHV round.

This last point leads lots of manufacturers to test against various SCHV (usually 5.56mm in the States) rounds, which is good. Do note that “Level III+” and “Level III++” are not NIJ certifications. Those are marketing nonsense. Read the list of test rounds carefully. Some materials used for Level III plates have problems with M855 steel-core (semi-armor piercing) rounds, and some other materials used in Level III plates have problems with the speed of M153 rounds, especially out of a 20″ barrel. Ideally, your plate will withstand both.

What about military plates? I can only speak for the US plates at present. These plates are made from ceramic materials. The US Military uses its own testing standard, not the NIJ one. SAPI1 plates are designed to resist three hits of “up to” M80 7.62x51mm ball. There’s also ESAPI2, which has a similar multihit standard against M2 .30-06 AP rounds. And then there’s XSAPI. Because somewhere out there, some terrorist has some exotic high power super armor piercing 7.62x54R mm that will punch through ESAPI plates and we need to stop that round too. It’s also multihit. Against something exotic, but I don’t know the test round. Maybe tungsten-cored .30-06?

Anyway, as you’d expect, more protection means more weight:

SizeDimensionsSAPI WeightESAPI weightXSAPI weight (Approx)
XS7.25″ x 11.5″2.8 lbs.3.75 lbs.4.7 lbs.
S8.75″ x 11.75″3.5 lbs.4.6 lbs.5.8 lbs.
M9.5″ x 12.5″4.0 lbs.5.5 lbs.6.9 lbs.
L10.125″ x 13.25″4.6 lbs.6.3 lbs.7.9 lbs.
XL11″ x 14″5.3 lbs.7.2 lbs.9.0 lbs.

Do note that all US Military plates assume they are mounted over the OTV, IOTV, or equivalent military-spec soft armor for them to perform as advertised. To the best I am able to determine, XSAPI plates have never been deployed in combat. They sit in depots because they’re too damn heavy and because the expected threat never materialized. Also, remember the above is per plate. Double it.

That military soft armor is tested to a different standard than the NIJ one. The military is concerned with fragmentation, primarily, so they look at the V50, i.e. the speed at which a given projectile must be going to have a 50% chance of penetration. This number is chosen because it’s a lot easier to work with than V0 from a measurements and statistics perspective. To simulate artillery fragments, the US Army tests with steel projectiles with weights of 2, 4, 16, and 64 grains. Steel doesn’t deform like lead pistol bullets do, so this is sort of a different challenge than regular pistol bullets. The V50 for a 124 grain 9mm NATO round against the current soft armor in the IOTV is about 1,525 fps, which is pretty similar to that of most Level IIIA soft armor panels. On the other hand, the NIJ requires Level IIIA panels to also stop .44 magnum rounds, and the US Military doesn’t.

Next time, we’ll take a more in-depth look at soft body armor systems.

  1. Small Arms Protective Insert 
  2. Enhanced Small Arms Protective Insert 

The General Issue Plate Carrier

The standard wisdom for current infantry protection is to use rifle plates and an armor carrier, which provides fragmentation protection for more area of the torso than the plates do. The armor carrier means that the lower abdomen, area around the plate, and the shoulder straps are going to be rated against fragments. Of course, this comes at a bulk and weight penalty. In Afghanistan, US special forces often took to wearing plate carriers. Plate carriers carry only plates. No soft armor panels, besides optional armor backers. They’re a lot lighter and less bulky. For mountain operations, this is awesome. Of course, there’s basically no artillery threat in Afghanistan. Let’s look at whether or not this makes sense in the general case.

We’re going to compare the IOTV with front and rear plates to a lightweight plate carrier with front and rear plates, specifically the Crye JPC. For the IOTV, we’re not going to include side plates and carriers, since the plate carrier we’re choosing doesn’t come with side plate pockets. Also, these plates provide protection for the abdomen, not the upper thoracic cavity, and the abdomen is a much less critical area. Both would need supplemental protection for the neck, shoulder, or groin. Removing accessories simplifies the comparison a little.

As usual, we’ll be using medium size items for comparison. We’ll also be using a pair of ESAPI plates for both. Two ESAPI medium size plates weigh 10.9 lbs. The medium size IOTV weighs 10.56 lbs. The medium size Crye JPC weighs 1.3 lbs. Since we’re using ESAPI plates, which require plate backers, we’ll need to add those, which gives us another 2.4 lbs.

So we might break this down into three options. The IOTV alone weighs 10.56 lbs. The JPC with plates weighs 14.6 lbs. The IOTV with ESAPI weighs 21.46 lbs. So switching to a a plate carrier with plates instead of an armor carrier with plates saves us about seven pounds in our example, though the exact weight will vary if we choose different models.

Clearly, the armor carrier with plates and plate carrier with plates are both going to be very effective against most rifle rounds. Also clearly, the plates will stop fragments that hit them. The armor carrier will provide fragmentation protection around the abdomen, around the border of the ESAPI plate and on the shoulder straps. Weight for marginal hit protection is what’s in question here.

Overall, I’m inclined to favor the plate carrier given the weight savings. There’s entirely too much load on our soldiers already. It may interest the reader to note that the ESAPI plates were deployed in Iraq to combat fragments from IEDs, so perhaps the traditional kevlar-type soft armor fragmentation protection is insufficient. It is important to understand the expected threat level.

Further weight savings might be obtainable with a different choice of plates. ESAPI plates (and the SAPI plates they were derived from) were intended to be worn over soft armor, and the soft armor backers are required to get the designed level of protection from the plates. We’ll look at some alternative plates in the near future.