Do you believe there will be a canonical explanation for why the Light Rifle is different in Halo 5? An unfortunate factor of 343i's decision to create a whole arsenal of Forerunner weaponry is that they can't really change the weapons' looks without giving a decent canonical explanation. With UNSC and Covenant weaponry, there doesn't need to be much canonical explanation, as it can easily be inferred that a change in appearance is the result of a new or different model of a weapon. Forerunner weaponry suffers from the unfortunate side effect of being the same as it was 100,000 years ago.