fastmongrel
1st Sergeant
replacing the magazine if he had acquired a spare).
There were no spare magazines. The only way to acquire a spare would be stealing one from someone else's rifle or removing one from a dead comrades rifle.
Changing a magazine on the No4 LE is not a trivial matter you have to pull the very stiff magazine release catch while pulling the tight fitting magazine out, a two handed job. Then you need to find your spare magazine which needs a good push and a slap to make sure it's locked in the very stiff magazine catch. Then as you went to all the trouble of stealing your spare you need to put it carefully back into a pouch or pocket. Then you can work the action and squeeze the trigger.
Your squad mates meanwhile open the bolt pull a charger out of pouch or bandolier load five or ten and have probably loaded another ten and fired them while your still fiddling with your spare magazine.
I can't say about the SMLE as I have never tried to swap a magazine on one but I bet it's the same.