The bills considered are H.R. 6869, H.R. 2311, and S. 1437. The data source was a 20 percent sample of all Federal offenders sentenced to prison in fiscal year 1974. Despite the predictive limitations of the data, they provide sufficient information on the characteristics of the population sentenced to prison in 1974 so that by applying reasonable assumptions, a fair range of projections as to the possible impact of the sentencing provisions of the various criminal code reform proposals is provided. Results show an estimated overall decrease from current law in average maximum sentences imposed under all three bills--a 17.5 percent decrease under H. R. 2311, and a 30.8 percent decrease under S. 1437. By applying two different assumptions about what may occur in sentences actually imposed as a result of statutory change, a likely range of possible sentences under each of the blls was developed. The range of average sentences imposed under H. R. 6869 was estimated to be 86 to 90 percent of the average imposed sentence under current law; the range under H. R. 2311 would be from 47 to 67 percent; and the range under S. 1437 would be from 72 to 86 percent. The elimination of good time by H. R. 6869 might result in a total increase of 8036.9 man-years served in prison, as estimated 29.5 percent increase. The almost total elimination of parole and the reduction of statutory good time under S. 1437 might result in a total increase of from 17,127.8 to 25,296 prison man-years, an estimated increase from 62.8 to 92.8 percent. (Author abstract modified)