I joined the marines in 1972 and we were issued s.l.r. and had to take it everywhere with us, I went in our locker and snap inspections had to try and find dust in it ,or that dreaded word RUST , god help anyone who had a weapon that was below standard. we used to put durex over the muzzle at night so that dust would not settle in the barrel at night. on the ranges the barrel would overheat fairly quickly. but it was yours, your responsibility, your best friend.