As the Mosin Nagant design evolved over the years changes were made to the outside contour of the barrel.  In Russia and the Soviet Union this primarily involved the length with smaller changes at the muzzle to accommodate various front sight bases.  In Finland the changes were more dramatic including the shape and outside diameter with a tendency toward heavier barrels.

This page illustrates the differences between the models and countries over time.  All dimensions are in inches and derived from direct measurement of actual barrels.  These are not "official specifications" and deviation should be expected.  The threaded end of the barrel not visible when assembled to the receiver and sight bases or dovetails are omitted for clarity.  Larger versions of the dimensioned images are available by clicking on the thumbnails.  The diameters at various points on the barrel are coded with a letter and included in charts for easier viewing.  In most cases the final figure is an average of a number of examples as shown in parentheses with any relevant notes.  Model variations with the same shape but different dimensions are included in these charts.  Overall lengths and the points on the barrel where diameters are measured are approximations.

The "3D" drawings link to Google's "3D Warehouse" where a detailed three dimensional model can be downloaded.  SketchUp (approximately 32meg) or SketchUp Viewer (approximately 6meg) are required to view and manipulate the models.  They are available for free and can be downloaded here.   Click here for a collection of all ten Mosin Nagant barrel models.

All Mosin barrel threads are identical and each barrel has a relief cut for the extractor on the end.

Muzzles of Mosin Nagant barrels are found in a variety of conditions.  Some are like new with sharp lands extended to the crown.   Others are worn, primarily from improper cleaning, with the lands tapering at the crown.  The Soviet Union and Finland both counterbored worn muzzles to recess the crown to a point where the lands are still sharp.  This was done to improve accuracy without the expense of shortening the barrel or rebarrelling the rifle.  Click on the thumbnails for larger versions.
Fresh Muzzle	Worn Muzzle	Counterbored Muzzle

M91 barrels are 30.5" inches long with a 2" tapered shank ending at a sharp radius to the tapered barrel.  1920s dated Finnish Tikka M91s and unstepped SIG M24s follow the same pattern with only minor differences in average measurements.