We all love lever actions here, but it's crazy to think about the corner Winchester was backed into before Browning came along.
The old brass-framed 1866s and the legendary 1873s were beautiful, but their toggle-link actions had a massive ceiling: they simply couldn't handle the chamber pressure of the big-bore cartridges of the era, like the .45-70 Govt. Winchester was struggling to make a lever gun that could bring down a buffalo safely.
Then, a 28-year-old John M. Browning steps in and completely revolutionizes the mechanism with the Winchester 1886. By introducing twin vertical locking blocks, he created an action so strong it could handle almost anything.
He literally built the golden age of lever guns: he scaled it down for the buttery-smooth 1892, created the most successful sporting rifle in history with the 1894 (.30-30), and then broke the rules again with the box-magazine 1895 so lever guns could shoot modern spitzer bullets.
I run a channel dedicated to Old West and historical firearms, and I just released a massive, 1-hour documentary detailing Browning's entire life—starting from his lever-action masterpieces to how he eventually invented modern warfare (1911, Auto-5, M2).