Your tracers seem to be losing velocity at a serious rate there
Apparently Bren gunners preferred worn-out barrels! But apparently not quite that
worn-out. On a slightly less flippant note, it was an extremely accurate gun, which isn't always helpful on full-auto, but it was apocryphally used as a sniper rifle ("apocryphal" as I'm not entirely convinced that the sudden change in its centre of gravity in the albeit tiny fraction of a second between pulling its trigger and firing was conducive to such things) but looking at the design it did have was what effectively a modern free-floated barrel which wasn't really inhibited by the way the gas system was implemented. Hard to say if it was designed with that in mind but it does have a lot of very clever features; I mean most of which were courtesy of the chaps at Brno who designed the Zb26(? I think), I'm not sure how much the guys at Enfield contributed beyond re-chambering it for .303 but it seems there were a number of changes there too.
Sorry, I sometimes get a bit nerdy when it comes to how stuff works. It's normally limited to programming, which is just as well because I'm a terrible shot.