http://www.border-barrels.com/
Right i always shoot in the barrel by 1 shot 1 clean for around 10 rounds, then 3 shots for maybe another 10 followed by 5 shots by 5, the barrel will need to be well cleaned after each shot, take your time,
To clean out the oil in the barrel i always use a dry patch first, followed by a bronze brush then meths on a patch give it a good clean, then dry patchs until they come out clean, 3 in 1, and WD 40 are to heavy a grade of oil, i would recommend you get a tin of dedicated gun oil.....
if going to shoot straight away leave the barrel as is or if not