Are "Flak Jackets" even "Bulletproof"?

Evaluations of the Capabilities of Obsolete Body Armor Systems

This is intended to be a reference for curious collectors, I assume no responsibility if shoot your self testing a flak jacket from the 60's...

There are three schools of thought in terms of military body armor. There are laymen who assume that all "body armor" is "bullet proof," There are people who read military literature who believe that "flak jackets" stop low velocity shell fragments but not bullets, and then there are people who actually test them and know the truth. Honestly, I don't care what your Drill Sergeant, MCT instructor, or Vietnam Veteran uncle said, I have a 2 lb bag of bullets I pulled out of various flak jackets.

This is my collection of body armor and helmets from the Korean, Vietnam, and both Iraq wars.

Nylon Body Armor

The M1952A, M69 and M79 Fragmentation Protective Vests

The M1952a (and later M69) fragmentation protective vest, consists of 12 layers of ballistic nylon fabric. The m1952a was fielded in Korea and Vietnam. With a few modifications (a lighter green cover, a protective collar, and vinyl inner layer) it remained in service as the m69 fragmentation vest. A further version of this vest called the M79 was developed by the British, it is distinguishable by its rubber shoulder patches and extra pounces. I tested an M1969 produced in the late 70's to evaluate the effectiveness of nylon body armor. It was surprisingly effective.

These are test samples of nylon body armor. After extensive evaluation I determined that nylon body armor has the following capabilities.

Based on my experiments, nylon based body armor might have been reasonably adequate for police until 9mm pistols began to surpass .38 revolvers in the hands of criminals. Having tested other samples besides the m1969 vest I cannibalized for this experiment, I have determined that ballistic nylon does degrade over time, and is less effective when backed by something hard like plywood, vs something soft like corrugated cardboard. I'm honestly not sure which material is closer to the modeling clay the NIJ uses to back body armor when measuring blunt trauma.

In terms of comfort and usability, I would consider the M1952A the best Korea/Vietnam era flak jacket. I don't like the M1969 model because the vinyl inner cover crinkles and adds volume to the vest. My tests show that nylon is superior to fiberglass for ballistic protection, so I consider the M1952A superior to the M1955 as well.




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Fiberglass Body Armor

The M1951 and M1955 Fragmentation Protective Vests

These are test samples of Doron Fiberglass armor.The m1955 (and earlier m1951) fragmentation vest, consist of 1/8 inch thick Donor fiberglass plates which cover most of the wearers torso, with ballistic nylon covering the shoulders. The m1951 design remained in service with the USMC through out the Korean War, until an upgraded version called the M1955 was developed and remained in service in the Marine Corps until the 1980's. The Samples I tested were from a late 1970's m1955.

Basted on my testing, Doron had similar capabilities to nylon body armor.

Fiberglass armor has some unique characteristics among ballistic armor materials. It will stop bayonet thrusts, but not most 9mm pistol rounds. I'm sure that if the plates were marginally thicker a functional "bullet proof" vest could be fabricated, but that might wind up negating any weight advantage over nylon.




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Kevlar Body Armor

The PASGT Vest

The PASGT vest, AKA "Body Armor, Fragmentation protective vest, Ground Troops", aka "The Vietnam surplus flak jacket" (as its know by servicemen who got issued one in Iraq). This is probably simultaneously the most under and over rated flak jacket in history. At gun shows they are often marketed as "US military issue Level 3a Kevlar vests" despite not being current issue or having an official NIJ threat rating. Where as they are sold at Army Surplus stores for about $50 as "flak jacket-not bullet proof" These are the facts on the PASGT vest. PASGT vest test samples

Based on my Experiments, The PASGT vest is

In terms of comfort and over all usability, I give the PASGT vest very high ratings. It's easy to put on, its fairly comfortable and light weight, and it provides adequate protection from the majority of handgun rounds. The only major flaw in the design of the PASGT vest is that it uses 13 layers of a Kevlar woven from an exceptionally heavy yarn. If the design used 20 layers of 500 denier Kevlar in place of 13 layers of 1500 denier Kevlar, the vest would offer the same level of protection but would be much lighter, thinner and more flexible. The only other minor flaw is that it is designed to be worn by ground troops so it might get uncomfortable sitting in a vehicle. I also find the desert camouflage outer covers to be a pain in the butt to put on, and they make the vest to bulky.

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1st Gen Interceptor Body Armor

Woodland, tri color desert or Coyote Brown, manufactured by Point Blank prior to 2004.

The problem with fragmentation protective vests is that they were all designed with a Cold War mentality that the next war would be fought with tanks, jets, and artillery, with very little face to face infantry combat. Thus, ground troops wouldn't "need" bullet resistant body armor. Vests with pockets that hold armor plates capable of stopping rifle rounds had been fielded sense the 1960's but were considered "to heavy" for infantry. (I will have reviews of several of these vests available in the near future)

The Interceptor Body Armor system (IBA), aka the Interceptor Outer tactical vest (OTV) was the first vest designed for US ground troops superficially designed to stop bullets, that also became standard issue.

The first version of the vest, which were available in woodland camouflage and coyote brown, and consisted of 28 layers of 600 denier KM2 Kevlar. Later Versions of the vest made by SDS contain 33 layers of a fiber similar to Kevlar called Twaron. Post 2004 vests (usually ones in ACU digital camouflage or DCU tri color desert camo) made by point blank or other military contractors contain 34 layers of ballistic fiber, consisting of 8 layers of Twaron, 18 layers of KM2, and another 8 layers of Twaron. An improved version of the vest, adopted by the Army, contains 40 layers of Twaron.

OTV test sampleFor the life of me, I couldn't figure out what prompted the change from 28 layers of km2, to the 8/18/8 twaron/km2 hybrid. This new combination basically made the vest marginally thicker, but of a nearly identical weight. After testing the ballistic panels from different versions of the OTV, I concluded that Twaron is actually a superior ballistic fiber to KM2.

OTV test sampleThe only handgun round I have ever been able to penetrate an Interceptor with is steel jacketed 7.62x25 Tokarev. By testing groin flaps and shoulder protectors, I found the 1st gen version of the interceptor could only stop 1 out of 3 shots, while subsequent versions could stop 3 out of 3 rounds. Groin flaps and shoulder protectors were tested, as they are cheaper and more available than the complete vests.

I give the interceptor positive reviews in terms of comfort and usability. It is easy to put on and take off in one step with out any complicated straps or buckles. The outer cover of the vest can be removed to make cleaning easier, or to change camouflage patterns. I suggest avoiding vests with coyote brown covers made by UNICOR as they are out of speck, and will cause the ballistic panels inside to bunch up around the edges.

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