Towed anti-tank guns were thought to be the primary means of defeating tanks. At the battle of Kursk for example, the Red Army deployed more artillery regiments than infantry regiments and towed gun densities reached over 20 guns per kilometer of defended tactical zone. A towed gun was much cheaper than a tank and could be concealed in a shallow position. When time allowed, dugouts with strong overhead cover could be constructed. Guns deployed on reverse slopes and in flanking positions could take a toll of attacking tanks. However, gun crews were vulnerable to artillery, mortar HE fire and enemy infantry. Their positions had to be carefully selected and once engaged, they generally could not redeploy. Experience strongly suggested that towed AT guns were less effective than self-propelled AT weapons and took heavier casualties.