The design itself is largely based on the Mauser M1893 and its successive models up to the Gewehr 98 rifle. The 1903 adoption of the M1903 was preceded by nearly 30 years of struggle and politics, using lessons learned from the recently adopted Krag–Jørgensen and contemporary German Mauser Gewehr 98 bolt-action rifles. They recommended replacement of the Krag.
A US Army board of investigation was commissioned as a direct result of both battles. Likewise, earlier in the day, a Spanish force of 540 regulars armed with the same Mauser rifles, under Spanish general Vara Del Rey, held off General Henry Ware Lawton's Second Division of 6,653 American soldiers and an independent brigade of 1,800 men for ten hours in the nearby town of El Caney, keeping that division from assisting in the attack on the San Juan Heights. The Spanish soldiers inflicted 1,400 casualties on the US in a matter of minutes.