In Late 1860 or early 1861, the Cosmopolitan Arms Company moved to a bigger space, part of an old water-powered mill in Hamilton, Ohio.  In this second location, the company created the Preproduction Cosmopolitan Carbine, the Transitional Cosmopolitan Carbine, and finally the Production-Type Cosmopolitan Carbine between 1860 and 1861 using Gross’ patent. The government granted the Cosmopolitan Arms Company a contract in 1861. After completing a shipment of 1,140 Production-Type Cosmopolitans to Illinois troops in mid-1862 and of an unknown type (most likely Transitional) to Union Cavalrymen from Kentucky during the ending months of 1862, Cosmopolitan Arms Company stopped producing Cosmopolitan carbines.1a​



According to historian Thomas Rentschler, “both carbines were essentially obsolete from the start,” mainly because they did not use a metallic cartridge.2 The cartridges for the Union carbines were made out of paper or were “linen-bodied with [a] paper base.”3 Upon firing the entire cartridge would be used; therefore, an extracting mechanism was not required.3  Similar to other carbines utilized in the Civil War, The Gwyn & Campbell used a percussion ignition system that operated with percussion caps. Generally speaking (the exact length differs depending on the  reference), the barrels of the Union carbines were 19 inches long,b and their total length was 39 inches. The guns weighed around 6.5 pounds and were .52 caliber.3b One flaw in all of the Union Carbine models is that there was no forearm to protect the marksman’s hand form being burnt by the hot metal after repeated fire.

 

As noted in Rentschler's study, the different models of the Union carbines went by a variety of names:c​

Preproduction Cosmopolitan

Traditional Cosmopolitan

Production-Type Cosmopolitan

Cosmopolitan to Gwyn & Campbell Transitional Type

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The carbines listed below have these dimensions:
.52 caliber, percussion cap priming system,
19-inch barrel, 39 inches long (total), 6.5 pounds,
and a 600-yard sight.d The following models
were outlined in Rentschler's study.



Gwyn and Campbell Type 1, Long Sight Model 

Gwyn and Campbell Type I, Short Sight Model

Gwyn and Campbell Type II, First Model 

Gwyn and Campbell Type II, Second Model 

Gwyn and Campbell Type II, Third Model

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A main difference between the Model I and Model II Gwyn & Campbell carbines was cosmetic. Model I’s hammer and guard lever curved more than Model II and were considered more “serpentine.” Model II sported a flatter handle and a slightly-rounded lever. Also, the two models’ lockplate screws entered the lockplates at different sides:  from the right on Model I and from the left on Model II.4



Although the Union Carbines were created right before and at the same time of repeaters’ rise to popularity, single-shot breechloaders still took precedent over other muzzleloading, smoothbore arms. At the time when breech-loading was still viewed poorly by some officials, the Gwyn & Campbell offered a new technology option.

a Flayderman’s Guide (5th ed.) attributes the 1,140 carbines just to the Illinois cavalrymen.5 ​

b According to the Kentucky Quartermaster General’s reports, as researched by Historian Thomas Rentschler, the Union carbine had three varying calibers:  .44, .54, .58.6 Flayderman’s and Gluckman only list the 52 caliber.7​​

c The Cosmopolitans and Transitional Type's dimensions were most likely the same; however, the author has not found any information on those with the exception of the Preproduction Cosmopolitan having the same .52 caliber, percussion cap priming system, a 19 in. barrel, 39 in. long, and 6.5 pounds.

d Flayderman Guide (5th ed.) records the barrel length as 20 inches for the Gwyn & Campbell and 19 inches long for the Cosmopolitan.7 Col. Arcadi Gluckman in Identifying Old U.S. Muskets, Rifles, and Carbines also has recorded the Gwyn & Campbell’s barrel length to be 20 inches.
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1 Thomas B. Rentschler,  Cosmopolitan and Gwyn & Campbell Carbines in the Civil War: A Definitive Illustrated History of Two Rare and Unusual Civil War Cavalry Carbines and Their Use in the Field (Lincoln: Andrew Mowbray Publishers, 2000), 22 -24.

2 Rentschler, Cosmopolitan and Gwyn & Campbell Carbines in the Civil War, 78.

3 Rentschler, Cosmopolitan and Gwyn & Campbell Carbines in the Civil War, 60.

4 Norm Flayderman, Flayderman’s Guide to Antique American Firearms … and their values, 5th ed. (Northbrook: DBI Books, Inc., 1990), 495.

5 Flayderman, Flayderman's Guide (5th ed.), 493.

6 Rentschler, Cosmopolitan and Gwyn & Campbell Carbines in the Civil War, 67.

7 Flayderman, Flayderman's Guide (5th ed.), 492, 495.

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