In contrast to division of work, division of labour is the specialization of an individual workers' or organizations' skills, through education, training, and practice.
AR15 Trigger Upgrades. 1  The trigger is one of the most crucial elements in achieving the highest level of accuracy from any firearm. Installation of a quality trigger will permit a light pull with little or no creep and overtravel.
The vast majority of AR barrels fall between the 14.5 military M4 type and the 20. M16 size, with 16 being currently the most popular for civilians. You can buy 14.5 barrels, but for most of us it would require a muzzle device at least 1.5 inches long, and permanently attached, to meet the legal 16 minimum.