Promoted ignition data from ASTM G124 have been of great value to the industry because they provide a basis for comparing the relative flammability of metal alloys in oxygen. In 2012, an industry-sponsored metals test and an analysis program were performed with the goal of applying statistical analysis methods to ASTM G124 data to create burn curves that plotted the estimated average burn length versus pressure for a given alloy at either the standard 3.2- or 6.4-mm-diameter rod. The results of the burn curves were presented in E. T. Forsyth et al., “Development of Burn Curves to Assist with Metals Selection in Oxygen.” This paper presents a methodology for improved statistical curve fitting to burn length data obtained from ASTM G124 tests. The methodology involves the use of a nonlinear least squares (NLS) regression using a logistic “sigmoidal” model. The method was applied to the data previously presented by Forsyth et al. for the following alloys: 316 stainless steel, 304 stainless steel, Inconel 625, Inconel 600, and Hastelloy C-276. Additionally, a tangent line method is introduced as a way to estimate the no-burn, transition, and complete-burn pressure regions of a material that has been tested. This work provides an improved approach to analyzing the burn behavior of metals using ASTM G124 data and presents new burn curves that can help to better characterize the relative flammability of metal alloys in oxygen.