Are these Level 2A vests?
Anyone interested in this subject should go Glocktalk.com and read the long history about this.
Basic story is Fed testing standards did not include moisture and heat related degradation tests.
Zylon degrades very much faster than other "blended" weaves when subjected to heat and moisture extremes.
There have been several failures/officers killed when zylon vests failed way before (read a year or less from manufacture) the 5 year expected life span was up.
Second Chance's in house scientist/engineer found this through his testing and was shut down by the company because (even though the vests were failing) "they met the standard."
You will see most failures have occurred in hot and or humid climates. Think CA/AZ.
Coincidently about the time Second Chance was denying internally that they had a problem with Zylon they were going public.
Now they are bankrupt and have been bought out.
Since the story says they used .357 Magnum, then according to Ballistic Resistance of Personal Body Armor NIJ Standard0101.04(pdf file) it is Level 2 testing, which is higher in ballistic protection than 2A. An explanation of NIJ BODY ARMOR CLASSIFICATION starts on page 13 of 57 of the pdf page number.
However, when you read footnote# 8 of the pdf link in comment# 1 on this thread it only states: "These tests used a conventional full metal jacketed 9-mm bullet weighing approximately 8 grams (124 grains)." That was for the first 28 samples tested. No range or velocity is specified. From that same pdf link in comment# 1 on this thread it only states:
"A total of 75 Zylon®-containing body armors were examined during the initial part of Phase II testing. One panel was randomly selected from each armor and subjected to penetration-backface signature9 (P-BFS) testing in a protocol similar to that used during Phase I testing. Each panel was tested using the two different calibers associated with the armors classification (Type IIA, Type II, or Type IIIA). Three shots of each caliber consistent with the NIJ Standard were fired (for a total of six shots), with one of the three shots for each caliber fired at a 30- degree impact angle. Unlike Phase I, during the Phase II P-BFS tests, all of the armor panels were tested in a wet condition in accordance with the NIJ standard.
" During the final part of Phase II testing, the companion panels will be subjected to ballistic limit testing to determine if, and how much, the ballistic limit has shifted since the armor model was originally tested for compliance to an NIJ standard. Zylon® yarns will be taken from selected armor panels and subjected to tensile testing. These results will be described in a subsequent report.
"A large number of the tested armor samples experienced penetrations and/or backface signatures that exceeded the maximum allowable limit of 44 mm (1.73 in) specified in the NIJ standard. Penetrations were observed in 48 of the 75 (64%) armor panels; 34 (45%) were penetrated more than once. Ten of the 75 (13%) armor panels were penetrated by all six rounds. Of the 27 armor panels that were not penetrated, all but two experienced at least one excessive backface signature. Figure 4 shows the number of armors tested from each threat level and test standard and summarizes the results of the P-BFS tests. Appendix C contains the complete results.
"Appendix D summarizes the data for specific armor types. While these results do not conclusively prove that all Zylon®-containing body armor models have performance issues, they clearly show that used Zylon®-containing body armor may not provide the intended level of ballistic resistance."
"9 Backface Signature (BFS): when armor is tested, it is mounted on clay backing materials whose consistency is controlled. After the shot, the depth of the clay deformation behind the armor panel is measured and recorded as the BFS."
The take home point is that Zylon, used in whatever level of body armor ballistic protection, degrades with exposure to the elements, especially water.
Since the Senate bill for the Lawful Protection of Firearms in Commerce has an amendment to study body armor used by law enforcement, which can be penetrated by 99.44% of centerfire rifle ammunition, folks pinged to this thread include more than the usual health and science ping list, but I tried to limit the rest to those who appreciate the RKBA.
On a lighter note, Age-Old Cures, Like the Maggot, Get U.S. Hearing
In a more grim note, Pakistan Now Says Scientist Did Send Koreans Nuclear Gear
Freepmail me if you want on or off my health and science ping list. Anyone can post any unrelated link as they see fit.