Question: The description says: "Buy all items from the Survival Weapon Armory", which is simple enough. 

My question is about the details: Do I have to buy every individual attachment for each individual weapon? Or perhaps say, if I buy the Red Dot Sight for the M4, will that be the only Red Dot Sight I have to buy to accomplish the achievement?

Answer: 
You have to buy all attachments at least ***once*** as well as the weapons. Buying a Red Dot (or any attachment) for one gun does counts for all. One of those dedication type achievements. 

If you're struggling, make sure you have each type of grenade launcher too.

Good luck!

[**Source & Little more Help**](http://www.youtube.com/watch?v=qeDuadJHK6g&feature=related)
This achievement can be done in single or multiplayer and can be done over many different missions (i.e., *not* in one mission). Make sure you buy the original handgun you are given. Picking up a gun does *not* count. You only need to buy the attachment for one gun, *not* for every gun.

What you need to get:

**HANDGUNS:**
Five Seven,
USP 45,
MP412,
Desert Eagle,
.44 Magnum,
P99

**MACHINE PISTOLS:**
G18,
Skorpion,
MP9,
FM99

**ASSAULT RIFLES:**
M4A1,
M16A4,
SCAR-l,
ACR 6.8,
AK47,
FAD,
G36C,
CM901,
MK14,
Type95

**SUB MACHINE GUNS:**
MP5,
UMP5,
MP7,
PM-9,
PM90M1,
P90

**LMGs:**
M60E4,
PKP Pecheneg,
MK46,
L86LSW,
MG36

**SNIPERS:**
MSR,
Dragunov,
RSASS,
L118A,
AS50,
Barrett .50 Cal

**SHOTGUNS:**
Model 1887,
USAS,
SPAS12,
KSG12,
AA-12,
Striker

**ATTACHMENTS:**
Holographic Sight,
Red Dot Sight,
ACOG Scope,
M203 Grenade Launcher (e.g. M4A1),
M320 Grenade Launcher (e.g. ACR),
GP25 Grenade Launcher (e.g. AK47),
Grip,
Shotgun