A History of Military Rifle Calibers: Small Caliber, High Velocity, 1886-1905

Almost four decades before the invention of smokeless powder, the advent of the Minié ball bullet made practical the standard infantry rifle, and with it the elongated projectile. This changed the fundamental physics of infantry weapon ammunition design, allowing longer ranged weapons firing oblong, high sectional density projectiles of smaller and smaller caliber. The arrival of smokeless powder in the mid 1880s accelerated this arms race: New projectiles, clad, or “jacketed”, with a hard metal to withstand the forces of acceleration generated by a high-velocity smokeless gun, took these principles to their extreme. By the late 1880s, infantry weapon caliber had shrunk from the ~0.69″ of the roundball-firing smoothbore muskets to less than a third of an inch (~0.30″), and smaller calibers were continuing to be adopted as the arms race to the bottom accelerated.

The basic principle these calibers were exploiting was the fact that a proportionally longer, smaller caliber projectile with the same sectional density as a larger one can be driven at higher velocities. This affords a longer maximum range, flatter trajectory, and greater penetrating power, all while reducing ammunition weight. The only limit to this trend was the propellant technology of the day; go too small in caliber, and too high in velocity, and the inefficient propellants of the period would quickly burn out all but the most metallurgically sophisticated rifle barrels. 6.5mm (0.264″) proved to be the limit; the United States Navy adopted the even smaller 6mm Lee Navy round in 1895 along with a fast-firing rifle designed by James Paris Lee, but the rifles were plagued by short barrel lives. Eventually, the caliber was abandoned after large portions of the Navy’s ammunition stockpiles were ruined by deterioration of the propellants, the final nail in the coffin of a promising but troubled rifle-caliber combination.


Right to left: 7.65×53 Argentine (1889), 6.5×52 Carcano (1891), 6×60 Lee Navy (1895), 5.2×68 Mondragon (~1894)


Experimental calibers during this period went even smaller; Colonel Rubin, who was in many ways the father of the modern .30 caliber cartridge, developed a 5.2x68mm cartridge with an innovative internal piston mechanism for Manuel Mondragon’s straight-pull Model 1894 rifle; it was just one of a series of small-caliber rounds designed for this project. German and British engineers experimented with a 5x57mm caliber, commonly called the 5mm Sturtevant, firing an 85gr bullet, in the first years of the 20th Century. Neither saw service.

Not all countries chased the small-caliber, high-velocity concept to its conclusion, however; many such as the Russians and British would stay content with their .30 caliber cartridges adopted around the beginning of the last decade of the 19th Century. Eventually, they would be vindicated by new developments in bullet technology…

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at nathaniel.f@staff.thefirearmblog.com.


  • 40mmCattleDog

    Its really a shame the Lee Navy’s service life was so low. The rifle and cartridge were impressive for the day and if the idea had come around maybe 20 or so years later maybe technology would have advanced enough overcome its flaws .

    • ostiariusalpha

      Certainly the coated propellants like the IMR powders would have turned the Lee into a truly formidable round. There were so many innovative and promising cartridges that went nowhere in the early 20th century for lack of the burn rate control that coated powders provide.

      • 40mmCattleDog

        Very true, history must have just missed this rifle’s moment. A 6mm high velocity clip fed straight pull sounds very attractive in an early 20th century battlefield.

        • Rap Scallion

          Can anyone say “Blaser”……works for the German made hunting rifles!

    • Kivaari

      Ass a spritzer boat-tail bullet and a less aggressive power and it would be fine. The rifle had weaknesses, including the ease of losing parts. The action was not easily run, like most straight pull rifles the energy savings and “speed advantage” was a wash. The 6mm Lee is a beautiful rifle. A friend has one with every accessories I can think of including the wood bulleted blanks. The 1895 cartridge would work well using todays technology. Trim that very tiny rim off and stuff them into an AR-type rifle and maybe the arguments about 6.5 v 5.5 would go away, for a day.

  • Rnasser Rnasser

    It is amazing how modern the 7.65×53 mauser (belgian/argentinian/etc.) still looks today.
    It does exactly what the 7.62×51 NATO does, only came 65 years earlier…

    • gunsandrockets

      The 7.65mm Mauser, the 7.5mm French, and 7.62mm NATO are all extremely similar.

      • Rnasser Rnasser

        They are… but the 7.65 mauser predated the french round by 40 years, and the 7.62 NATO by 65 years!
        The 7.65 mauser was introduced the same year as the .303 british, and two years earlier than the 7.62×54 russian, two rounds that look like dinosaurs compared to it.

        • gunsandrockets

          However, have you looked closely at the case rim and extractor groove of the French 7.5mm? Or the 7.62mm? There are subtle but probably important differences from the earlier Mauser-type cases which I believe were intended to improve reliability in automatic and semi-automatic firearms.

          • Rnasser Rnasser

            True! but these are very minor differences, The geometry of the rim and extractor of the 7.65 mauser is very close to that of the 7.92×57 (a tried round if there ever was one), but the rim is noticeably thinner.

          • gunsandrockets

            That’s interesting. I would have assumed identical geometry for all the Mauser cartridge case heads.

  • CommonSense23

    What was the average barrel life of the Lee Navy.

    • ostiariusalpha

      According to the June 1st report of Ensign N.C. Twining of the Ordnance Department from the 1897 Annual Reports of the Naval Department: Reports of the Secretary of the Navy (pg. 323), the original 135gr. copper washed steel-jacketed loads resulted in a barrel life of “less than 3000 rounds,” whereas their 112gr. tin plated copper-jacketed replacements at a lower pressure had a barrel life of “practically 10,000 rounds.”

      • Oh good, you went and looked in the Annual Reports so that I didn’t have to. 🙂

  • Rock or Something

    That 5.2×68 Mondragon is quite a quirky looking round.

    • Cmex

      Reminds me of something that starts with “ch” and ends with “ode”.

  • Renegade

    I could nitpick on a day-old post about how the army had moved down to .58 with the 1855 Springfield, but I’m just not that classless.

    • ostiariusalpha

      Heck, many of the Whitworth sharpshooter rifles fired a 45 caliber bullet. They were the SCHV of their era.

    • What did I say that was inconsistent with that?

  • Rap Scallion

    So with all of the talk about the 6.5 Grendel we are in fact trying to reinvent the wheel???? WHY did we get rid of the M1 or M 14 for something new???? Why are we going back to the future with rifles and pistols for infantry?????? Am I missing somethging here or are we simply on the 223 varmint cartridge, which from all indications is really NOT doing a LR job in places line the sandbox????? How stupid are Americans, we just keep reinventing the what we condemmed and threw out like some obsolete mustache cup! The up grades from the Krag, to the 06, to the M1, to even the M14, was all in good common sense…..then came the M16 and it’s children and we still have a black plastic varmint rifle!

    Sorry but I just don’t get this ongoing search for a “NEW” rifle or pistol for the military!