The very large single piece cast brass hilt is 141 millimeters long and has a feather or scale pattern on the sides and bottom of the grip.  There is a forward swept round finial on the bottom of the guard and no finial on top of the muzzle ring.  The press stud spring is rather large at 57 millimeters long and 8.2 millimeters wide.  The press stud is typical Collins style construction.  There is no blade rivet in the  center of the cross guard.  

The muzzle ring inside diameter is 18.1 millimeters and it stands about 9.2 millimeters above the hilt flat.  The lug slot's top edges are straight and unchamfered.  There is no guide slot.    

Jim Maddox viewed two pristine examples of this bayonet without scabbard that were in storage in the Belgian Army Museum in Brussels.  The museum only identified them as American.  Fortunately, Jim managed to take a couple of pictures.

Jim Maddox

Albert Hardin, "The American Bayonet 1776 - 1964" #170, shows a bayonet labeled INTRENCHING KNIFE, MODEL 1874 (SERGEANT'S) which appears to have an identical hilt although the blade is totally different.  Hardin states that the cast brass hilt is 5.375 inches (137 mm) long and the bore is .718 inch (18.2 mm) in diameter.  Hardin also states that at least one example is marked on the blade flat, AMES MFG CO / CHICOPEE / MASS.

Albert Hardin, "The American Bayonet 1776 - 1964" 

Edward Hull, "Peabody Firearms, Plate25-7, shows a bayonet for the Peabody Martini rifle with a similar brass hilt.  It differs in the height of the muzzle ring above the hilt flat and in blade style that is identical to the Peabody Martini Model 1874 sword bayonet. Hull states that the observed brass hilted bayonets have a style of fish scale grip that was commonly used by the Ames Manufacturing Company on bayonets it manufactured in the 1880 period and the purpose for which Ames made them is unknown; they may have merely been samples of what could be made, for use on either the Peabody Martini or Martini Henry rifle.  

For more details, go to Unknown Peabody Martini Bayonet Type 2.

The connections to the Peabody Martini rifle and Ames Manufacturing Company are pretty strong but the purpose and numbers produced are still uncertain.  If its purpose was for sales samples then the numbers produced would be very limited.  

In comparing this bayonet to the well known steel and leather hilted Model 1874 Peabody Martini saber bayonet, it was found that the hilt length, muzzle ring diameter and the lug slot dimensions were identical.  Other than the blade size, a perfect match except for one issue.  The height of the muzzle ring above the hilt flat is significantly different between the two models.  The steel hilted model's muzzle ring is 5 millimeters above the hilt whereas the brass hilted model is 9.2 millimeters.