Because it lacks an electric charge, the neutron is a useful probe of the electroweak framework of the Standard Model (SM), which describes the process as a particle undergoes radioactive decay. Neutrons are the simplest example of B-decay, which provides a unique suite of tests for fundamental parameters of electroweak theory.The neutron lifetime, rn, can be used in conjunction with its other decay properties to extract Vud. This can then be combined with other particle decays to investigate the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix. By itself, neutron b-decay can be used to study the origins of matter in the universe, and even hunt for new novel decay modes. The UCNr experiment, at Los Alamos National Laboratory (LANL), is the world's most precise measurement of the neutron lifetime. UCNt traps Ultracold Neutrons (UCN) in a bottle of permanent magnets for periods of time longer than the neutron lifetime. This work presents the results of two calendar years of UCNr data taking, resulting in a lifetime with both statistical and systematic uncertainties below 0.3 s. The analysis has utilized new methods to minimize the uncertainties due to backgrounds and initial estimation of the number of trapped UCN. A suite of Monte Carlo simulations, in conjunction with data-driven measurements, have been used to demonstrate the loss rates of UCN in UCNr are below the statistical precision of the experiment. This analysis leads to a blinded lifetime result with uncertainties on rn of -+0.26 +0.21/−0.16s, or a relative precision of 4 x 10−4.