.43 Spanish / 11.15x58R (Lee Precision Data)

.43 Spanish / 11.15×58R (Lee Precision Data)

The .43 Spanish (also known by its metric designation 11.15×58R) is a classic black-powder military cartridge first produced in the late 1860s. Originally developed for Remington Rolling Block rifles that were widely exported to Spain, Mexico, and South American nations, this round became one of the most iconic large-bore black-powder cartridges of its era. Lee Precision recognizes this historical significance by including reloading data and die support for the caliber in its manuals, making it feasible for modern handloaders to safely reload and shoot these guns with properly developed loads.

Lee Precision’s published data for the .43 Spanish / 11.15×58R focuses on a traditional black-powder style bullet, approximately .446"–.448" in diameter, in keeping with the bore sizes of most surviving rifles. This cartridge was originally loaded with heavy lead bullets weighing in the 370–400 grain class, propelled by substantial charges of black powder — typically 70 to 82 grains of FFg or FFFg depending on rifle condition and barrel length. Lee’s reloading advice maintains this historical balance, stressing that these old military actions were designed for the slower, more benign pressure curve of black powder, and modern smokeless substitutes must be worked up very conservatively if used at all.

In Lee Precision data, the recommended primer type is large rifle, and bullet seating tensions emphasize firm but not excessive neck tension to ensure consistent ignition and avoid gas cutting in these older chambers. Lee also highlights the need for meticulous case preparation — trimming, deburring, and consistent neck sizing — because the cartridge’s long rimmed case and heavy bullet place unique demands on sizing dies and chamber fit. A proper shell holder and Lee’s full-length resizing dies ensure that brass reforming yields uniform neck tension and straight cases that chamber smoothly.

Velocity expectations derived from Lee’s load data and black powder equivalents place muzzle velocities in the 1,300–1,450 fps range from typical 30–32" roll-block barrels. When using black powder or reduced smokeless loads, energy on target remains sufficient for medium game at modest ranges, while recoil stays within manageable levels for shooters accustomed to full-bore vintage rifles. Lee’s reloading table suggests incremental work-ups from safe, conservative charges, with careful logging of each step and observation of primer condition, case expansion, and chamber performance.

Lee Precision’s data also cautions that many .43 Spanish rifles today have barrels of unknown condition, steel quality, or throat erosion — conditions that can greatly affect safety with modern propellants. Handloaders are encouraged to slug the bore, verify groove diameter, and choose bullet sizes that engage the rifling without excessive pressure. Lee’s emphasis on careful, slow progression through loads — combined with consistent chronographing — helps reloaders achieve reliable accuracy while respecting the limits of these antique arms.

Today, the .43 Spanish / 11.15×58R remains a favorite among black-powder cartridge rifle (BPCR) shooters and collectors. With Lee Precision reloading support, enthusiasts can responsibly shoot and reload these historic rifles, preserving a unique piece of firearms history while enjoying the distinct experience of vintage big-bore shooting.

Source: Lee Precision load data & manuals (historical reloading information for the .43 Spanish / 11.15×58R).