Editing Bulletproof vest (section)

==Soft and hard armor==
[[File:NIJ LVLIIIA Kogelvrij vest, BA8001.jpg|right|thumb|upright|A level IIIA soft armor low-profile vest]]
Modern body armor is generally split into one of two categories: soft armor and hard armor. Soft armor is typically made of woven fabrics, like Dyneema or Kevlar, and usually provides protection against fragmentation and handgun threats. Hard armor usually refers to [[ballistic plate]]s; these hardened plates are designed to defend against rifle threats, in addition to the threats covered by soft armor.{{sfn|GUIDE BODY ARMOR Selection & Application Guide 0101.06 to Ballistic-Resistant Body Armor|2014|pages=6–7}}

===Soft armor===
Soft armour is usually made of woven fabrics (synthetic or natural)<ref name="natural fibers">{{cite journal |last1=Naveen |first1=J. |last2=Jayakrishna |first2=K. |last3=Hameed Sultan |first3=Mohamed Thariq Bin |last4=Amir |first4=Siti Madiha Muhammad |title=Ballistic Performance of Natural Fiber Based Soft and Hard Body Armour- A Mini Review |journal=Frontiers in Materials |pages=608139 |doi=10.3389/fmats.2020.608139 |date=9 December 2020|volume=7 |bibcode=2020FrMat...7..440J |doi-access=free }}</ref> and protects up to NIJ level IIIA.<ref name="spartan armor overt/covert"/> Soft armour can be worn stand-alone or can be combined with hard armor as part of an "In-Conjunction" armor system. In these in-conjunction systems, a soft armor "plate backer" is usually placed behind the ballistic plate and the combination of soft and hard armor provides the designated level of protection.{{sfn|GUIDE BODY ARMOR Selection & Application Guide 0101.06 to Ballistic-Resistant Body Armor|2014|page=6-7}}

=== Hard armor ===
{{Main|Ballistic plate}}
[[File:Surviving attack more than just dumb luck for sergeant (army.mil 451588).jpg|thumb|upright=0.9|An [[Small Arms Protective Insert|ESAPI]] plate with battle damage following two bullet strikes. The wearer survived the incident thanks to the plate and was later invited to take receipt of its damaged section.<ref>{{cite web |last1=Vergun |first1=David |title=Surviving attack more than just dumb luck for sergeant |url=https://www.army.mil/article/175668/surviving_attack_more_than_just_dumb_luck_for_sergeant |publisher=[[United States Army]] |access-date=9 July 2023 |date=26 September 2016}}</ref>]]
Broadly, there are three basic types of hard armor [[ballistic plate]]s: [[ceramic plate]]-based systems, steel plate with [[spall]] fragmentation protective coating (or backer), and hard fiber-based laminate systems. These hard armor plates may be designed to be used stand-alone or "In-Conjunction" with soft armor backers, also called "plate backers".{{sfn|GUIDE BODY ARMOR Selection & Application Guide 0101.06 to Ballistic-Resistant Body Armor|2014|pages=6–7}}<ref name="midwest armor plate backer">{{cite web |title=MASS IIIA Soft Plate Backers |url=https://midwestarmor.com/products/mass-iiia-soft-plate-backers/ |website=Midwest Armor |access-date=14 July 2022 |archive-url=https://web.archive.org/web/20220714000332/https://midwestarmor.com/products/mass-iiia-soft-plate-backers/ |archive-date=14 July 2022}}</ref>

Many systems contain both hard ceramic components and laminated textile materials used together. Various ceramic materials types are in use, however: aluminum oxide, boron carbide and silicon carbide are the most common.<ref name="Holmquist1999">{{cite web |last1=Holmquist |first1=T J |last2=Rajendran |first2=A J |last3=Templeton |first3=D W |last4=Bishnoi |first4=K D |date=January 1999 |title=A Ceramic Armor Material Database |url=https://apps.dtic.mil/sti/pdfs/ADA362926.pdf |journal= |publisher=[[United States Army Tank Automotive Research, Development and Engineering Center|TACOM RD&E Center]] |archive-url=https://web.archive.org/web/20220714015137/https://apps.dtic.mil/sti/pdfs/ADA362926.pdf |archive-date=14 July 2022}}</ref> The fibers used in these systems are the same as found in soft textile armor. However, for rifle protection, high pressure lamination of ultra high molecular weight polyethylene with a Kraton matrix is the most common.

The [[Small Arms Protective Insert]] (SAPI) and the enhanced SAPI plate for the [[United States Department of Defense]] generally has this form.<ref name="Lee2001">{{cite journal |title=Penetration Failure Mechanisms of Armor-Grade Fiber Composites under Impact |first1=B L |last1=Lee |first2=T F |last2=Walsh |first3=S T |last3=Won |first4=H M |last4=Patts |first5=A H |last5= Mayer  |journal=Journal of Composite Materials |volume=35 |issue=18 |year=2001 |pages=1605–1633 |doi=10.1106/YRBH-JGT9-U6PT-L555|bibcode=2001JCoMa..35.1605L |s2cid=135870731 }}</ref>  Due to the use of ceramic plates for rifle protection, these vests are 5–8 times as heavy on an area basis as handgun protection. The weight and stiffness of rifle armor is a major technical challenge.  Density, hardness and impact toughness are among the materials properties that are balanced to design these systems. While ceramic materials have some outstanding properties for ballistics, they have poor fracture toughness. Failure of ceramic plates by cracking must also be controlled.<ref name="Savage1990">{{cite journal |title=Ceramic Armour |last=Savage |first=G |journal=Journal of the Institute of Metals |volume=6 |issue=8 |pages=487–492 |date=August 1990}}</ref>  For this reason many ceramic rifle plates are a composite. The strike face is ceramic with the backface formed of laminated fiber and resin materials. The hardness of the ceramic prevents the penetration of the bullet while the tensile strength of the fiber backing helps prevent tensile failure. The U.S. military's [[Small Arms Protective Insert]] family is a well-known example of these plates.

When a ceramic plate is shot, it cracks in the vicinity of the impact, which reduces the protection in this area.  Although NIJ 0101.06 requires a Level III plate to stop six rounds of 7.62×51mm M80 ball ammunition,<ref name="BallisticStandardsBAN">{{Cite web|url=https://www.bodyarmornews.com/ballistic-standards/|title=Ballistic Standards|website=Body Armor News|language=en-US|access-date=2019-11-25}}</ref> it imposes a minimum distance between shots of 2.0 inches (51mm); if two rounds impact the plate closer than this requirement permits, it may result in a penetration. To counter this, some plates, such as the [[Ceradyne]]<ref name="LFAA4NamedCeradyne">{{cite web |title=level 4 Plate? |url=https://www.lightfighter.net/topic/level-4-plate |website=Lightfighter Tactical Forum |access-date=6 April 2020}}</ref> Model AA4 and [[Ceradyne#IMP/ACT|IMP/ACT]] (Improved Multi-hit Performance/Advanced Composite Technology) series,<ref name="CeradyneIMPACTBrochure">{{cite web |title=Ceradyne Armor Brochure |url=http://ceradyne.com:80/Uploads/Ceradyne_ARMOR_Brochure.pdf |website=Ceradyne |archive-url=https://web.archive.org/web/20070204070056/http://ceradyne.com/Uploads/Ceradyne_ARMOR_Brochure.pdf |access-date=6 April 2020 |archive-date=4 February 2007 |url-status=dead }}</ref> use a stainless steel crack arrestor<ref name="SOCOMRecallsSPEARS">{{cite web |title=Questions Surround SOF Body Armor Recall |url=https://www.militarytimes.com/off-duty/gearscout/2012/11/24/socom-recalls-thousands-of-spear-ballistic-armor-plates/ |website=Military.com |date=8 August 2017 |access-date=12 June 2020}}</ref> embedded between the strike face and backer. This layer contains cracks in the strike face to the immediate area around an impact, resulting in markedly improved multi-hit ability;<ref name="HASCCrackArrestors">{{cite web |title=STATEMENT BY GENERAL PAUL J. KERN COMMANDING GENERAL U.S. ARMY MATERIEL COMMAND BEFORE THE COMMITTEE ON ARMED SERVICES SUBCOMMITTEE ON EMERGING THREATS AND CAPABILITIES UNITED STATES SENATE SESSION, 108TH CONGRESS ON THE DEFENSE LABORATORIES AND S&T OVERVIEW UNITED STATES ARMY MARCH 31, 2003 |url=https://www.globalsecurity.org/military/library/congress/2003_hr/kern.pdf |website=Global Security |publisher=U.S. Congress |access-date=6 April 2020}}</ref> in conjunction with NIJ IIIA soft armor, a 3.9&nbsp;lb IMP/ACT plate can stop eight rounds of 5.56×45mm M995, and a 4.2&nbsp;lb plate such as the MH3 CQB can stop either ten rounds of 5.56×45mm M995 or six rounds of 7.62×39mm BZ API.<ref name="MH3HAPB4C">{{cite web |title=Multi Hit III++ Hard Armor Plate – MH3HAP-B4C |url=http://www.paracletearmor.com/Armor/MH3HAPB4C.htm |website=Paraclete Armor |archive-url=https://web.archive.org/web/20050216023818/http://www.paracletearmor.com/Armor/MH3HAPB4C.htm |access-date=6 April 2020|archive-date=2005-02-16 }}</ref><ref name="MH3IMPACTPlate">{{cite web |title=Miscellaneous gear and equipment |url=https://beta.sam.gov/opp/ec471e0428cda3712f7e5b960078a737/view |website=beta.sam.gov |publisher=U.S. General Services Administration |access-date=12 June 2020 |archive-date=12 June 2020 |archive-url=https://web.archive.org/web/20200612172205/https://beta.sam.gov/opp/ec471e0428cda3712f7e5b960078a737/view |url-status=dead }}</ref>

The standards for armor-piercing rifle [[bullet]]s are not clear-cut, because the penetration of a bullet depends on the hardness of the target armor, and the armor type. However, there are a few general rules. For example, bullets with a soft lead-core and copper jacket are too easily deformed to penetrate hard materials, whereas rifle bullets intended for maximum penetration into hard armor are nearly always manufactured with high-hardness core materials such as [[tungsten carbide]].<ref>Manfred Held "Threats to Military Transport Aircraft:A Technical Review " Journal of Battlefield Technology, Vol 6, No 2, July 2003 11440-5113 © 2003 Argos Press</ref> Most other core materials would have effects between lead and tungsten carbide. Many common bullets, such as the [[7.62×39mm]] M43 standard cartridge for the AK-47/AKM rifle,<ref>Joe Poyer''The AK-47 and AK-74 Kalashnikov Rifles and their Variations'' North Cape Publications Copyright 2004</ref> have a steel core with hardness rating ranging from Rc35 [[Steel#Material properties|mild steel]] up to Rc45 medium hard steel. However, there is a caveat to this rule: with regards to penetration, the hardness of a bullet's core is significantly less important than the [[sectional density]] of that bullet. This is why there are many more bullets made with tungsten instead of tungsten carbide.

Additionally, as the hardness of the bullet core increases, so must the amount of ceramic plating used to stop penetration. Like in soft ballistics, a minimum ceramic material hardness of the bullet core is required to damage their respective hard core materials, however in armor-piercing rounds the bullet core is eroded rather than deformed.<ref>Charles E. Anderson, Jr., James D. Walker,  "An analytical model for dwell and interface defeat" International Journal of Impact Engineering vol 31 issue 9 2004.</ref>

The US Department of Defense uses several hard armor plates. The first, the Small Arms Protective Insert (SAPI), called for ceramic composite plates with a mass of 20–30&nbsp;kg/m<sup>2</sup> (4–5&nbsp;lb/ft<sup>2</sup>). SAPI plates have a black fabric cover with the text "7.62mm M80 Ball Protection"; as expected, they are required to stop three rounds of 7.62×51mm M80 ball, with the plate tilted thirty degrees towards the shooter for the third shot; this practice is common for all three-hit-protective plates in the SAPI series. Later, the [[Small Arms Protective Insert#ESAPI|Enhanced SAPI]] (ESAPI) specification was developed to protect from more penetrative ammunition. ESAPI ceramic plates have a green fabric cover with the text "7.62mm APM2 Protection" on the back and a density of 35–45&nbsp;kg/m<sup>2</sup> (7–9&nbsp;lb/ft<sup>2</sup>); they are designed to stop bullets like the .30-06 AP (M2) with a hardened steel core. Depending on revision, the plate may stop more than one. Since the issuance of CO/PD 04-19D on January 14, 2007, ESAPI plates are required to stop three rounds of M2AP. The plates may be differentiated by the text "REV." on the back, followed by a letter. A few years after the fielding of the ESAPI, the Department of Defense began to issue XSAPI plates in response to a perceived threat of AP projectiles in Iraq and Afghanistan. Over 120,000 inserts were procured;<ref>{{Cite web|url=https://www.foxnews.com/printer_friendly_wires/2009Feb05/0,4675,BodyArmor,00.html|title=Better body armor means more weight for troops
|website=[[Fox News]]}}</ref> however, the AP threats they were meant to stop never materialized, and the plates were put into storage. XSAPI plates are required to stop three rounds<ref>{{Cite web|url=https://ciehub.info/spec/PD/FQ-PD-07-03D.pdf|title=Purchase description of the XSAPI}}</ref> of either the 7.62×51mm M993<ref>{{Cite web|url=https://beta.sam.gov/api/prod/opps/v3/opportunities/resources/files/b314f0ef42a89143542880078453ad17/download?api_key=null&status=archived&token=|title=Brand Name Justification for Ballistic Plates.pdf (opens in new window)}}{{Dead link|date=April 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> or 5.56×45mm M995<ref>{{Cite web|url=https://www.govinfo.gov/content/pkg/CHRG-109hhrg33590/html/CHRG-109hhrg33590.htm|title=House Armed Services Committee hearing discussing XSAPI development}}</ref> tungsten-carbide armor-piercing projectiles (like newer ESAPIs, the third shot occurs with the plate tilted towards the shooter), and are distinguished by a tan cover with the text "7.62mm AP/[[Tungsten carbide|WC]] Protection" on the back.<ref>{{Cite web|url=https://cdn.discordapp.com/attachments/562765631645286421/650839361348173824/pix488839178.jpg|title=Image of back of XSAPI|date=December 1, 2019|access-date=April 7, 2020|archive-date=September 9, 2021|archive-url=https://web.archive.org/web/20210909030241/https://cdn.discordapp.com/attachments/562765631645286421/650839361348173824/pix488839178.jpg|url-status=dead}}</ref>

Cercom (now [[BAE Systems]]), [[CoorsTek]], Ceradyne, [[TenCate Advanced Composites]], Honeywell, DSM, Pinnacle Armor and a number of other engineering companies develop and manufacture the materials for composite ceramic rifle armor.<ref name="CorporateMember">{{cite web |url=http://ceramics.org/acers-community/corporate-members-2/ |title=Corporate Member Listing |publisher=Ceramics.org |access-date=2010-08-12 |archive-url=https://web.archive.org/web/20100828105354/http://ceramics.org/acers-community/corporate-members-2/ |archive-date=2010-08-28 |url-status=dead}}</ref>

Body armor standards in the [[Russian Federation]], as established in [[GOST]] R 50744-95, differ significantly from American standards, on account of a different security situation. The [[7.62×25mm Tokarev]] round is a relatively common threat in Russia and is known to be able to penetrate NIJ IIIA soft armor.<ref>{{Citation|title=PSM Shooting: 5.45x18mm vs 7.62x25mm on Soft Armor| date=July 2017 |url=https://www.youtube.com/watch?v=zapDoI_q3JM |archive-url=https://ghostarchive.org/varchive/youtube/20211211/zapDoI_q3JM| archive-date=2021-12-11 |url-status=live|language=en|access-date=2019-11-25}}{{cbignore}}</ref> Armor protection in the face of the large numbers of these rounds, therefore, necessitates higher standards.<ref>{{Cite web|url=https://www.armourshield.com/ballistic-standards.php|title=Ballistic Standards – Armourshield: Manufacturers of Quality Body Armour / Bullet Proof Vests: Established 1974|website=www.armourshield.com|access-date=2019-11-25}}</ref> GOST armor standards are more stringent than those of the NIJ with regards to protection and blunt impact.<ref>{{Cite web|url=https://www.sentineltailors.com/GOST-R-EN.pdf|title=Russian Federation GOST-R 50744-95|website=www.sentineltailors.com|access-date=2020-01-13|archive-date=2020-03-31|archive-url=https://web.archive.org/web/20200331142156/http://www.sentineltailors.com/GOST-R-EN.pdf|url-status=dead}}</ref>

For example, one of the highest protection level, GOST 6A, requires the armor to withstand three 7.62×54mmR B32 API hits fired from 5.10m away with 16mm of back-face deformation (BFD). NIJ Level IV-rated armor is only required to stop 1 hit of .30–06, or 7.62×63mm, M2AP with 44mm BFD.<ref>{{Cite web|url=http://www.sentineltailors.com/ballistic-standards-2-39.html|title=Ballistic Standards|website=www.sentineltailors.com|access-date=2019-11-25|archive-date=2013-09-14|archive-url=https://web.archive.org/web/20130914053313/http://www.sentineltailors.com/ballistic-standards-2-39.html|url-status=dead}}</ref>

===Trauma plates===
Trauma plates, also called trauma pads, are inserts or pads which are placed behind [[Ballistic plate|ballistic armour plates/panels]] and serve to reduce the blunt force trauma absorbed by the body; they do not necessarily have any ballistic protective properties. While an armour system (hard or soft) may stop a projectile from penetrating, the projectile may still cause significant indentation and deformation of the armour, also called backface deformation. Trauma plates help protect against damage to the body from this backface deformation. Trauma plates should not be confused with soft armor or with ballistic plates, both of which do inherently provide ballistic protection.<ref name="bulletproofzone trauma pads">{{cite web |title=The Importance of Trauma Pads |url=https://bulletproofzone.com/blogs/bullet-proof-blog/the-importance-of-trauma-pads |website=Bulletproof Zone |access-date=14 July 2022 |archive-url=https://web.archive.org/web/20210518121722/https://bulletproofzone.com/blogs/bullet-proof-blog/the-importance-of-trauma-pads |archive-date=18 May 2021}}</ref><ref name="nij body armor guide">{{cite web |title=GUIDE BODY ARMOR Selection & Application Guide 0101.06 to Ballistic-Resistant Body Armor |url=https://www.ojp.gov/pdffiles1/nij/247281.pdf |website=National Institute of Justice |access-date=14 July 2022 |archive-url=https://web.archive.org/web/20220423115919/https://www.ojp.gov/pdffiles1/nij/247281.pdf |archive-date=23 April 2022 |date=December 2014 |page=8 |ref={{harvid|GUIDE BODY ARMOR Selection & Application Guide 0101.06 to Ballistic-Resistant Body Armor|2014}}}}</ref><ref name="trauma pad ar500">{{cite web |title=Trauma Pad |url=https://www.ar500armor.com/trauma-pad.html |website=AR500 Armor |access-date=14 July 2022 |archive-url=https://web.archive.org/web/20210505210627/https://www.ar500armor.com/trauma-pad.html |archive-date=5 May 2021}}</ref>