Updated: Nov 21, 2022
The 'slide' holster is little appreciated and when they are mentioned on forums there are always know-it-alls who warn of their 'dangers'. You know what surprised me in my career? Doggone it, they're a commercial success!
The earliest of the concept, though not literally a 'slide-on' type such as the Hume that is slotted at both sides like the pancake design it preceded, is this one by Bedell Rogers of TX mid 20th century. The two are for autos, note the exposed trigger and the provision to hold the mag button off the inside of the holster, a hallmark of the Rogers' work for L.A. Sessums' and his own line of Sunday scabbards:
Likely you today are most familiar with the slide promoted by Jeff Cooper, who was always on the ready to find a local maker for someone else's design (he did this 'favor' for Bruce Nelson, too). It did have a hazard which was the front sight catching during the draw, and on a Glock-type that could mean the sight being pulled off the slide. But as you can see, Jeff had the expected common sense to have ramp front sights on his 1911s (aka 'holster sights'):
The Yaqui is a slide made without using the twin slots through the layers.
Later it was turned into a screw-together assembly by the likes of Galco.
When I was tasked with creating a range of non-leather holsters for Shooting Systems that had been Assault Systems and is now I-Don't-Know-What Systems, I included a slide and it stayed in their range. This range is the first appearance of my trademark 'skeleton slots' that no maker has copied (yet) because they don't understand them :-).
Ditto for the DeSantis range that I did for Gene and it has stayed in his range, too:
And for Aker with the range I dubbed its 'Flatsider' range. It has a 'peep-toe' configuration at the muzzle. "Red, your designs put me on the map!" said Kamuran Aker.
These last three all have my personal trademark styling sensibilities that I first lent to the Bianchi Holsters range, yet none c/b confused with the other; so are unique to the various marques.
"Holstory -- Gunleather of the Twentieth Century -- the Second Edition" is available at www.holstory.com and is posted to you from inside the USA by the printer itself.