Number of rounds a rifle can handle really depends on the caliber and its usage. For instance, with 5.56/.223 rifles used for training or general purposes, I usually start to see a noticeable drop in accuracy around the 8k-12krd mark and sometimes even more if the barrel has been well cared for. .308 barrels can stay in good shape for about 3k-4k rounds while 6.5 Creedmoor often shows a decline sooner usually around 2k-3k rounds especially in precision setups. When it comes to pistol calibers, they’re a different beast entirely and can often handle tens of thousands of rounds before barrel wear becomes a real concern.