Well, I want Lily's silenced assault carbine, it wasnt in her inventory as my companion, but she has it equipped
I killed her, no dice


What can I possibly do? I tried equipping her with a better gun but she wouldnt use it
any advice?

You haven't seen her carbine's stats so how do you know what you gave her was better? In any event to answer your question you can't end of story. Unless your playing on the PC you can't take a companions default equipment. [oh god how I wish I could be rid of Cass's hat]

Ugh, well thats crappy
I only went for her because I was originally searching for an assault carbine, why not take one with added perks?
Oh well, guess thats over
Thanks for the help, and I agree, cass has an ugly hat.
It wouldnt be so bad if it was just brown, not straw -.-

Oh and, one thing
I DID see that stats
Fallout wikia ftw.
besides, common sense told me that something with over 70 attack is better than any fully automatic weapons bullets.
If not, then that weapon is just supremely overpowered.

If you checked the wikia you'd know you couldn't get the weapon from her. So I'm guessing you weren't looking at
http://fallout.wikia.com/wiki/Lily%27s_assault_carbine

Try giving her something like a sniper rifle[and ammo obviously] I have found that companions may appear to keep with their own weapon but switch to something else in their inventory when entering combat.

Who said I checked out how to get it? just looked at how good it was compared to assault carbine.