Armored Jacket AV = 8/6
Lined Coat AV = 6/4

"Jacket" - Light outerwear that generally doesn't cover very far below the waist.
"Coat" - Heavier outerwear that generally covers signficantly below the waist, frequently to the back of the knees.

8, as a number, is larger than 6. (The same is true for 6 versus 4).

What am I missing here?

I know that this has been this way for a couple of editions, and that the first answer is going to be that the Armored Jacket is more obviously heavy armor than the Lined Coat is, but that leaves two points:
- The difficulty of called shots to shoot around armor is directly linked to the armor value, which doesn't produce the results I want.
- If Armored Jacket is really ludicrously bulky and obvious, this should be listed in the item description.

I'm thinking "Jacket" = Flak Jacket, though that might be incorrect.

Just poor choice of words, but it has been that way since the beginning. The lined coat should have just been called an Armored Duster or something.

The way it always sat with me was Lined doesnt sound like all that much armor. it might cover more of the body but with a much lighter/thinner armor. where as the armored jacket dose what most body armor should covers most the vital organs with a good amount of armor. yeah you can still take a leg/arm/head shot but a chest shot isn't going to kill you (most of the time. damn panther cannons)

Allso, while the torso-portion of the Jacket does not have to be very flexible and can thus be packed full of Armor, the oposit is true for the Coat, especialy the part covering the legs, so it is less heavily lined. This does nothing for your called shot problem. But that lies with SR, for the sake of simplicity having no hit zone system. Maybe you can rationalize the odd called shot rules somehow, I´ve stopped trying 2 Editions ago and used hit zones ever since (though it realy complicates the game, so I use them only for called shots, while every regular hit goes to the torso).

allso, the lined coat gives a bonus to consealability (allways have before so im guessing that its doing so now allso, do not have the book yet). this the jacket do not.

any runner worth his nuyen knows that if a person is wearing a coat rather then a jacket, he is packing heavyer weapons...

I had always figured the Jacket to be made of a thicker material and was kind of big and puffy like a Ski Parka and the Coat would be made of something thinner and lighter.

I usually assume lined coat to mean a standard trenchcoat with a bit of reinforcement. Mostly the high armour value is due to the excellent coverage of the body it provides.
The armoured jacket on the other hand I take to be something like a cross between a present day bullet proof vest and a motorbike jacket, fairly bulky, covbering only upper body but with excellent protection on the torso.

And for what I think an armoured jacket would look like:
A present day motorcicle jacket, with shoulder, elbow and back shielding
obviously it wouldn't be in the silly bright blue colour

SR4's basic types of armor, if memory serves, run along these lines:

4/0-Armored Clothing
6/4-Lined coat, armored vest
8/6-Armored jacket
10/8-Full body armor

Correct me if i'm wrong, i'm away from my BBB.

"Armored clothing" is really low-profile... basically clothes made out of bullet-resistant fabric, mostly aimed at being comfortable and providing *some* protection without being really annoying.

The "lined coat" to me has always been a trenchcoat made with bullet-resistant fabric, and maybe some lightweight plastic or ceramic ribbing to provide some impact protection... it's more comparable to armored clothing than combat armor. One of the annoying things about wearing a real-life trench around is that if you're letting it hang open/untied and you've got some heavy stuff in the pockets, it tends to bonk around. If you had any serious plating put into the coat (the kind you need in order to get any real protection against higher-energy ammunition) it'd be a pain in the ass to wear. As it's something you toss on over your clothes, it can be made of heavier or less-comfortable fabrics (since it's not really form-fitting the way a shirt is) which is why it provides better protection than armored clothing, despite covering approximately the same area.

The "armored vest" is modern torso body armor, in a way. Lots of bullet-resistant fabric layers and some trauma plates to resist high-energy impacts that might go through fabric alone (kind of like how we can upgrade some modern IIIA vests, which can stop most pistol ammunition, by the addition of plates which add a noticeable amount of weight and annoyance, but allow them to stop some rifle ammunition). While it protects noticeably less of your body than an armored coat (the arms and legs are exposed, rather than mostly covered), your torso has *significantly* better armor on it, which is why they have the same armor value.

The "armored jacket" is basically an armored vest on the torso, but the jacket extends the protection compared to your basic armored vest to include your arms (fabric in the sleeves, and quite possibly some sort of bracer or armguard built in along the bones of the arm, leaving the joints free to move) and probably hangs a little lower over the pelvis, which is why it's got a higher armor rating. It's worth noting that the difference between "full body armor" and an "armored jacket" is all of 2 points of B/I... I generally figure that while there may be some styling choices to make the "jacket" more street-style friendly, it's construction for purposes of protection is pretty much the same as a suit of full body armor... i'd give a player wearing a suit of FBA without the leggings on it the same protection as an armored jacket. Older versions of SR featured a number of archetypes of "soldiers" and "mercenaries" who wore armored jackets, most likely because they felt that the loss of protection on their legs (and not really anywhere else) was worth what they gained in mobility, and not getting tired on long marches. "Military" armored jackets probably resemble Full Body Armor much more than they resemble a biker jacket.

My opinion:

Armor Jacket is more easy going if you are in a run; its easy to wear if you need to be stealthy. You can hide a couple of pistols beneath them...

Imagine trying to hide behind something, having to pay attention that your long coat doesn't give you out... Or hanging head down while trying to infiltrate a building witha long coat on... How about the rear wheel of your bike "eating" the coat while you drive... Of course you can conceal bigger guns/blades beneath it, but that is it, in my opinion...

The book, however, makes it pretty clear that while you are wearing a 'jacket', it's obvious that it's armored. As much as I'd like a Class IV Seahawks jacket, i don't think they're going to make them any time soon