https://armypubs.army.mil/epubs/DR_pubs ... _22x12.pdf
(4) Smoking. The sniper should not be a smoker or use smokeless tobacco. Smoke or an unsuppressed smoker’s cough can betray the sniper’s position. Even though a sniper may not smoke or use smokeless tobacco on a mission, his refrainment may cause nervousness and irritation, which lowers his efficiency.
Ancient 1903 Manual
http://www.ibiblio.org/hyperwar/USA/ref ... M23-10.pdf
4. RATE OF FIRE AND EFFECTIVE RANGE.-The maximum rate of accurate fire with this weapon depends upon the skill and the position of the operator and the visibility of the target. It varies from 10 to 15 shots per minute. The effectiveness of rifle fire during combat decreases as the range to the target increases. Its use at ranges greater than 600 yards is unusual.
Marines Heard From
https://www.marines.mil/Portals/59/Publ ... 130206-573
Special ForcesEach sniper team consists of a team leader and a scout-lllliper. Both are trained 8541 's. Each team is equipped with:
• M40Al BDiper rifle with a UNERTL lOX telescope • Standard Ml6 service rifle • M49 20X spotting scope • Wide-angle binoculars with mil seale • .45 caliber service pistols • Starlight scope if neceaaary • Radio
https://archive.org/details/milmanual-f ... nt/page/n0 (archived)