I think 20 years of friendship, joint study of other 'weapon systems' & ideas, mechanical aptitude and skill, hard work and dedication, probably had a lot to do with the end product.

BTW: Erik Jorgensen died in 1896, at age 48. (I assume smoking and being overweight may have shortened his life).

Photo: Col. Ole Herman Johannes Krag promoting the Krag-Jorgensen rifle in Paris, 1900. (Col. Krag died in 1916, at age 79).

---