I'm about 99% sure the XP bonus doesn't apply on my weapons anyway. I turn in a bounty for 5000 experience and I'll see my gun move. I do the highest level daily that should give like 7000 experience? I see no visible gain. This is ever after using the gun in the whole level. I've viewed it before the final kill so as not to skew it with XP I've gained from kills and I compare it after I hit the results screen. Can anyone confirm it actually does? It goes to armor just fine.