The old Bootnecks are tough bas***ds, and don't need too many of them, to make there presence known. I used the British version of the FN FAL, we called it the SLR 7.62, phased out for the SA-80 5.56mm. However, I much prefer the M-16, but theres only one weapon i'd give all of those for and thats the GPMG (Gimpy) 7.62 HMG, I love that weapon. The M-16 is a better rifle than the SA-80, and the boys from the Mountain and arctic warfare cadre use the M-16, as well as the Commando battalions Recce troops. The SA-80s only effective as an individual weapon up to 300 metres, 600 metres if used as a section support weapon. But its big Brother, the LSW is good up to 800 metres, but thats nothing compared to my baby, the Gimpys 1100-1800 metres.
Don't know about the oxygen bottles, I would have thought the mountain troops were acclimatised (the Mountain and arctic warfare cadre definately are) to the heights. One things for definate though, 'don't f**k with the Royal Marine Commandos'. I had a Training Corporal at ITC Catterick last year, who had passed the all-arms commando course at the Royal Marines Lympstone, He'd go out on runs with his dog, and by the time he'd finished running, the dog needed to be carried.
Look up MAW in google, as for running with dogs, at HMAS Condor they used to come up on the bus from Dundee.Keeping up with them sure tired me out.