i want to buy a couple "bullet proof" Lexan panels to go in my brief case.  it is a nylon case that needs something to stiffen the walls and i think hey great i will get a couple sheets of Lexan that i can also use if the situation goes sour.  the brief case is made so i can samwitch my papers between the two layers of Lexan each be up to 1/2" thick.

so how thick a sheet do i need to stop say:
45acp
44 mag
.223 ball
.223 green tip?
thanks,

no way.
i will drape it over my head while i put together my own ar-15.

Save your money

I'm thinking the brief case would be awfully heavy if Lexan was used, but what do I know?  Lexan seems heavy to me - at least enough of it to be bulletproof.

Lexan, by its self, is not 'bullet proof', In most cases it is a laminate of Lexan and Plexi with a soft Polymer bonding agent. If I remember right, a 44 mag rated sheet is around 1 1/4" thick.

We used a 2.5 ft. x 3ft. x .25 ft. sheet of Lexan on a trackhoe to protect the operator.  That sheet weighed several hundred pounds.

I have heard of gang members in other states using this to "harden" vehicles or using individual sheets as ad hoc body armor. It might be good for a few shots of a lower-velocity round and is probably better than nothing. I would be interested to see some hard data on how it performs.

My fraternity pledge brother, Eric Babilius's Father had one of the patents for Lexan when he worked at GE.  He had this beer mug made of the stuff that he would bet us we couldn't break.  He was quite a dork.  anyway, one day DJ Cowan just grabbed the damn thing and threw it down a well we had at our frat house.  Pretty tuff stuff really.  I think that's what they make those bullet proof panels you see at banks.  

Lexan is the GE brand of polycarbonate, and can be made in layered products. By itself, it is tougher but softer and breaks down in sunlight. You also have to clean using non abrasive methods because it will scratch and haze. It can be doped ed to make it more UV resistant, sandwiched in glass to make it scratch resistant etc.  Do a search for "ballistic polycarbonate" and you should find plenty of info.

I recall one time (It was within the last six months) Castro was giving a speech and he fainted/collapsed @ the pedestal.. A guy in the front row row jumped out and unfolded a "briefcase" to cover/shield his body( they didnt know what was up right away). Seemed very effectge .
Im thinking ... if Castro's Sec. detail deployed it, it "must" work.. didnt look very heavy at all..( judging by the fast response time)
all in all I was impressed at the response.

edited to add **************

The overall lenth of the expanded/unfolded "briefcase" was aprox 5 - 6 feet.. as it covered the still standing castro completly from view

The bullett proof lexan used to protect gas station attendants is well over an inch thick, and can stop a .44 mag. I had a friend that worked behind one, and we threw a can of soup at it, and it barely put a dent in it.

The big advantage of lexan as a ballistic material is its transparency, which apparently you don’t need.

I suspect you’d be much better off buying an old unit of Kevlar body armor off e-bay, cutting it to the right size (with a really sharp pair of scissors, one layer at a time), and using it.

A really thick piece of aluminum also might be a better way to go.

It’s going to take a lot to stop a .223!

It is not very bullet proof, My father recently had a large piece of 2" thick "bulletproof" lexan put into The front entrance of His Office building.  I took a scrap peice of it, about 2' square and 2" thick, to go shoot at.. I decided to start small and work my way up, a .22 left marks in it, a 9mm left slightly bigger dents/marks. Then I shot it with a 30-06 once and it absolutly exploded..  maybe it is more structurally sound when it is in a larger sheet, but it did not do very well, I was not impressed.

My shop teacher had some 1 cm thick scrap pieces of Lexan(I think it was Lexan anyway).  I remeber taking about 2" x 2" squares and putting them in a vise. I would tighten the vise until the lexan was noticably bowed upwards and then take a small hand saw and make a [b]very[/b] shallow cut on the top of it.  After doing this you could hear the lexan start making crackling sounds, which would start increasing in rapidity...until...BOOM! The lexan would snap and the pieces would hit the ceiling of the shop room(about 30 feet up).  

The stuff seems pretty strong to me, but I doubt it could stand up to rifle fire, unless it was fairly thick.

Old body armor seems to be the way to go.
If you really want level III protection.
you can get those 10"x?" trama plate.

Whan I used to travel to some unfriendly forign land. I stuff panal from a vest in our back pack.

One vest if good enough for two. Its a pretty good idea, since we are unarmed, its better to have the protection behind you because you be running away as fast as you can.

I'd think that a couple of ceramic trauma platesc and a piece cut from a bullet resistant vest, would be the way to go.  

All armor is ablative, that is to say, it's protection value degrades with every hit it absorbs. Whether it is lexan, kevlar or layered spectra, ceramic and titanium.  A single hit will cause material fatigue and stresses that subsequent hits will add to until the cumulative stress and damage causes the structure to fail.

Even tank armor will eventually fail if you keep hammering away at it with small arms fire. It'll take a hell of a long time and perhaps millions of rounds of ammo, but eventually you'll get through it.  That is of course, if the tankers don't incinerate your ass with a HEAT round or perforate you with coax fire, or just plain run you down under the tracks first.

A test of armor to determine upper levels of protection had better start with the heaviest planned threat first.  I'd hit it with .30-06 AP first, Then, moving on to a fresh plate, step down to .30-06 or 7.62 ball, then move to the next plate.  Once the plate actually sustains the first shot, then you can add another shot and see how MANY rounds it'll take before failing. If the plate can only sustain the one hit without failure, then it's protection against that round is marginal in my opinion.  Sustaining two hits would seem a minimum of reasonable protection to me.

Bulletproof windows in cars for instance, need to be changed regualrly, probably annually and even more frequently in sunny environments.  Even with UV protectant layers, they degrade from the sunlight.

If youa re truly concerned that you might become a target for gunfire, line your priefcase with panels cut from body armor and wear a vest. If the vest needs to be light to fit in with your lifestyle, at least it'll offer some protection and maybe prevent an entering bullet from penetrating to damage vital organs.

My solution to the problem is to stay the f8ck away from cities.