If the chain bar becomes too severely worn, the chainsaw will not operate efficiently or properly. Though there are ways to extend the life of chain bars, they will eventually need to be replaced. The Husqvarna 501959245 3/8 Pitch .050 Gauge 45DL 12" Chainsaw Bars Fits T435, 327P4, 327P5x, 316E, 334T, 335 XPT, 338 XPT, 323P4, 325P4, 326P4, 326P5x, 327P5x....