Halo 3

I heard that the gamerscore required to get them varies for some reason, also I heard there is a glitch in the game that will not let people get the sholders sometimes. Though normaly you need 700-850 GS to get them.

I have 715 and I have had them since I had 590 GP

It's NOT Bungie exclusive.
You need 750+. It took me 990 to get them.
To be honest, it's not that hard to get 990. I'm only having trouble with frenzy and two for one.

The way i got them was to unlock 30 acheevments, that is the easiest way to unlock them

It is glitched, sometimes you get it, sometimes you don't.

It is not based on gamerscore. Instead, they should be unlocked totally when you get 30 achievements for the game.

I got security a long time ago I think u gotta hav a certain

its mainly based on Getting 750+ Gamerscore, since i got it at 750. if you wear it, there is a less chance you'll lose it if you get it.

My gamerscore (from Halo 3) is about 560... and I have the security shoulders.

I found this on a web site and think it might help you:

Security Shoulder Pieces: Earn 750 of 1000 gamerscore on Halo 3. Due to inconsistency, this armor permutation is not always given at 750. There are some reports that the Security Shoulders need a minimum of 500- 995 gamerpoints, even though the official guide to Halo 3 lists the requirements as 750 (could also be total metagame points). Even then, the armor permutation may be unlocked, and then re-lock itself after a time, as has been reported. The only way to keep it permanently is to get all the achievements. This permutation may need the player's model to have accessed online to unlock it. An alternate way to unlock is to gain all 49 achievements. For some players it can be unlocked, then lock itself, but to re-unlock you it you need to change to Mark VI then change it back.

Hope this helps!

my brother has found himself with them multiple times, but whenever he puts them on, it turns them into "mark VI" shoulders.

i really dont think he has even 500 gamerscore.