There has been a considerable amount of discussion and opinions advanced with regard to this subject here on the forum and in lots of other venues.
Most everyone knows that the NYPD began issuing revolvers in 1895 by direction of Theodore Roosevelt when he served as President of the NYC Board of Police Commissioners. He also mandated revolver qualifications. Weapon of choice by the way was the Colt New Police in.32 long. They purchased 4,500.
Firearms carry, use, and training continued to evolve over the decades along with tactics. In fact it was a long time coming before the average american LE Officer carried any extra ammo. Some Officers nationwide began to be survival oriented and became students of the doctrine. One topic was the secondary weapon and from that some became proponents of going to the second weapon when the first was empty. Remember this was for the most part during the era of dump pouches and belt loop loader. Remember too that most Officers are not gun folks and are not too fond of firearms training, especially extra firearms training.
The New York Reload became a part of our Speech, it is even in Wiktionary. However if you have an interest in this subject spend a little time on the net and read up on the true Masters of the Missouri Reload.
The War Between the State's was a very brutal conflict and in no region more so that the Trans Mississippi theater in Missouri. Guerrilla bands on both sides took cavalry warfare to an art form.
Most weapons of the time were muzzleloaders even though this conflict saw the invention of many improvements and technologies.
The favored weapon of the mounted forces in the region was a revolver, not just one or even a pair.but in some case 4,6,8 or more. A horseman with 4 belt holstered revolvers and another brace in saddle holsters could deliver 36 shots. A devastating rate of fire faced by a soldier armed with a single shot muzzleloading rifle.
The most common revolvers seen in period images and in literature about the time were from the houses of Colt and Remington with some preference for the.36 caliber and some for the..44 caliber.
Size wars back then?
The Remington being a solid frame design facilitated changing out the cylinder for a loaded one as one method of getting back in the fight. It even helped spawn guerrilla clothing style, the shirt at least because it became pretty much standard for them to wear a similar style. Made of a variety of cloths and materials the guerrilla shirt was decorated heavily with embroidery by a female loved one and all were adorned with deep chest pockets to carry extra pre loaded and capped cylinders.
Look up images of Missouri Guerrillas, and both the Massacre and the Battle of Centralia to find out more about these men who contributed greatly to to concept of the NY Reload.