"Rurik"s main battery consisted of four 50-caliber (cal.) guns in a pair of twin gun turrets, mounted fore and aft on the centerline. These guns and their turrets were designed by Vickers specifically for "Rurik". The turrets were oval-shaped and sat atop a working chamber that handled shells and propellant charges brought up from the magazines below. One set of hoists brought the munitions up to the working chambers from their magazines, and another set transferred them up to the turrets. In addition to the split hoist arrangement, anti-flash precautions included a sprinkler system in the magazines and provisions to quickly flood them in the event of a serious fire. The guns fired armor piercing (AP) or high explosive (HE) shells at a muzzle velocity of . At their maximum elevation of 21 degrees, the guns had a range of for the AP round and for the HE variant. The guns had to be returned to between −5 and 8 degrees of elevation to be reloaded. The guns had a rate of fire of two shots per minute.