How to Headspace the Nagant Model 1895 revolver.

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How to
Headspace
the
Nagant Model 1895 Gas Seal Revolver

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I'm the husband of the owner of this website and I would be pleased to share with you some information that took me years to figure out for myself.

"Headspace" in a revolver is the distance between the rear of the cylinder face and where it contacts the support mechanism of the closed chamber. In the specific case of the Nagant Model 1895 gas seal revolver, this is measured between the rear cylinder face and the bearing surface of the Firing Pin-Hole Block (when the Cylinder is fully moved forward overcoming the Cylinder Bushing Spring tension). The thickness of the rim on the cartridge base (.050" for a standard 7.62 Nagant cartridge) reduces this headspace by that exact amount. Indeed, the thickness of the rim helps to control the headspace in rimmed cartridges, and any rim thickness that is non-standard will alter the margins of safety & function that the factory intended. In the M1895, the space remaining (between the base of the cartridge and the Firing Pin-Hole Block) must also include another .003" (for Single Action operation) and .005" (for Double Action operation) to insure reliable functioning under varying conditions. Any additional space beyond this is purely slop. The average headspace on most M1895 revolvers (the total space between the rear cylinder face and the base of the Firing Pin-Hole Block) seems to be .064" (.057" being the smallest I've ever measured and .069" being the largest).

If you're the owner of a Nagant Model 1895 gas seal revolver, then you'll appreciate the need to determine the headspace of your handgun...especially if you reload ammunition for this weapon. As with all firearms, proper headspace is a vital aspect that directly relates to safety & function. The Soviets seem to have paid fairly close attention to the headspace of their guns because all current imports of the M1895 (that I've measured) exhibit functional headspace (although some guns are a little too sloppy for my liking).

Step-by-Step Instructions

     * As a matter of curiosity, the standard rim thickness is as follows:
            » For a standard 7.62 Nagant case, this will be exactly .050". (note: surplus Soviet ammunition measures exactly .050" every time).
     * Push the Cylinder as far forward as possible, overcoming tension from the Cylinder Bushing Spring...don't let the Cylinder spring back!
     * With an automotive Feeler Gauge, measure the distance between the rear cylinder face and the Firing Pin-Hole Block.
     * Repeat this same process on each of the cylinder bores. Record the SMALLEST & LARGEST of these 7 measurements.
     * These measurements will be the SMALLEST and LARGEST Headspace of your specific revolver.