Official Journal of the Winchester Arms Collectors Association $10.00 Fall 2012 www.winchestercollector.org
Page 36 Check Us Out at www.WinchesterCollector.org The Winchester Model 1873 Set Trigger by Stephen Rutter, M.D. If you’ve seen that little screw behind the trigger of some 1873 Winchesters and wondered about it, this is the story. With the new model Winchester 1873 rifle, Oliver Winchester finally had, as Buffalo Bill Cody wrote, “…the most complete rifle now made.”i It combined the lever activated toggle-link mechanism of Smith & Wesson to cycle the rounds, the receiver-mounted loading gate of Nelson King that first appeared on the rim-fire Winchester 1866, allowing a closed magazine tube and the addition of a forestock, a vast improvement over the Henry rifle. And the reloadable, more powerful centerfire .44 WCF brass cartridge was the crowning improvement for the 1873. An additional interesting feature that first appeared as a special order item was the set trigger. Simply stated, the set trigger is composed of additional internal parts that convert the standard trigger to one that can be adjusted to reduce the pull weight to the shooter’s choice. In other words, into a hair trigger. This was advantageous for the target shooter as well as some hunting situations. Like the standard trigger, it could also be fired without “setting” the trigger. It is estimated that no more than 5% of the approximately 720,610 model 1873 Winchesters made between 1873 and 1923 were so equipped, many on the earlier guns and on all of the “1 of 1000” and other special, fancy guns.ii As with the early guns themselves, several design changes to the set trigger were also made, seemingly to not only improve function, but to also simplify manufacture or repair and to reduce production costs. To understand the set trigger design and function, it helps to review the standard trigger. The first standard triggers for the model 1873 combined the trigger and sear as one piece; the sear being the component that engages the half and full cock notches of the hammer until the correct amount of pressure has been applied to the trigger to disengage the sear from the full cock notch and allow the hammer to fall and fire the gun. When the safety bar was added at about the 28,000 serial number range, the trigger and sear were made as two separate, though interacting pieces. The safety bar required that the sear be separate from the trigger for the safety to function.iii Guns with set triggers were never able to utilize the safety because of the very different configuration of the modified and additional parts. It is interesting to note at about that same 28,000 serial number range, the trigger pin became external again, like the model 1866, having been inside the receiver of the model 1873 up to that time.iv Later in the production of the model 1873 Winchester, about the 89,000 serial numbers, the hammer screw, that had been external up to that point, was replaced by an internal pin and the trigger pin was again returned to an internal position. These changes allowed the trigger mechanism to be assembled into the lower tang before placement in the receiver. The exact dimensions and details of the upwards of 16 to 18 modified or additional parts that make up the set trigger assembly are beyond the scope of this discussion and are enumerated elsewhere.v However, a general description is in order to provide the reader with an overview of how the set trigger works. After the gun is cocked, the set trigger is engaged by pushing the trigger slightly forward until a “click” is heard, indicating that the sear kickoff catch is set on and holding the sear kickoff under tension.vi The adjustment of the screw determines how far the trigger must be moved rearward to release the kickoff by adjusting the amount of overlap the catch has on the kickoff. The following parts are found on both the standard and set trigger guns, though other than the trigger pin, they are modified considerably for the later: Trigger: The external trigger is more slender and tapered than the standard trigger and can also be easily identified by the tiny adjusting screw immediately behind the trigger on the right side.vii The internal portion of the trigger is larger and very different, as the pictures show. Sear: Because the sear can be released in two ways, its shape is likewise different from the conventional, non-set trigger sear. If the gun is fired without setting the trigger, the sear is rotated forward by the flat surface on top of the trigger. When the set trigger is used, the sear is knocked forward by the sear kickoff, releasing the hammer.viii Hammer: The hammer itself is generally the same size and shape on both. However, the hammer of the set trigger also had one of two types of additions in the form of a sear over-ride or “fly” as described below. The set trigger hammer had either a hole for the “outside over-ride” or a slot and pin for the “center over-ride” as well as milled relief to allow movement of the fly. The notches are about half the width of the standard hammer. The stirrup attachment brackets on the rear are on the left side rather than the center. Stirrup and Pin: The stirrup that connects the hammer to the main spring and the pin attaching it to the hammer are shorter and they are off-set to the left side, as is the main spring. Main Spring: To allow room for the additional necessary set trigger parts, the main spring is tapered to the left to engage the hammer stirrup on the left side of the hammer.
Fall 2012 Page 37 Trigger Pin: This is the same for both, other than the external to internal production change mentioned previously. Lower Tang: The set trigger lower tang is modified with an asymmetric trigger opening to accommodate the right rear projection of the trigger that holds the adjustment screw. There is an added threaded hole on the bottom of the tang for the attachment of the spring screw as well as side holes for the two additional pins holding the additional parts. The following parts comprise the remaining set trigger components not found in the standard trigger assembly: Adjusting Screw: This screw, less than a third of an inch long with a tall, slotted head and about 85 threads per inch, is used to position the sear kickoff relative to the trigger. By this action, the amount of overlap of the sear kickoff catch can be varied, thereby adjusting the trigger travel needed to fire the gun. Turning the screw in moves the sear kickoff up, reducing the contact with the catch, resulting in the gun firing with less trigger movement. All adjusting screws are slotted, though many show damage or loss of one side of the head at the slot or they are completely broken off or frozen in the hole. Several very early guns, up to the 300 serial number range, with a set trigger have been seen with an adjusting screw that has a small transverse hole below the slot and at right angles to it. A small tool was noted to accompany a cased Winchester ’73 with a set trigger at the Cody Firearms Museum. It was described as having one end flattened with a small pin at the other that fit this hole in the adjustment screw.ix It was likely intended as an alternate method of turning the screw during early production. Sear Over-Ride: Early in production, this over-ride was one piece, consisting of the flat “fly” with an integral pin machined at right angles to attached it to the hammer, fitting into a pivot hole in the left side of the hammer. This early type is known as the “outside sear over-ride”. Later in production, the sear over-ride was a separate flat piece that fit into a slot near the center of the hammer base and held with a separate pin, the “center sear over-ride”. This was likely an easier production method than the earlier one-piece. Both performed the function of keeping the sear from catching in the half-cock notch of the hammer as it rotated forward to strike the bolt. Sear Kickoff: After the trigger, this piece is the next largest piece and there are two variations. They are the same size and shape, however, those used with the center sear over-ride hammer have a machined away semicircular area on the front, left side, to allow movement of the center sear over-ride. Sear Kickoff Catch: This delicate piece catches the notch in the kickoff when the trigger is moved forward to “set” the trigger. The amount of catch overlap is determined by the adjustment screw. Sear Kickoff Catch Pin: The pin has two diameters: the right portion, that fits the hole in the kickoff catch, is a smaller diameter than the left side. The shoulder on the pin keeps the catch upright and stable to the right side of the tang, though able to pivot. The corresponding lower tang holes are likewise different sized, allowing this pin to only be moved into position from left to right, which is the opposite of most Winchester rifle pins that are removed left to right and reassembled right to left. Three Springs: These springs control the action of the following parts and are stacked, bottom to top, as follows: 1. Sear Spring: The middle size spring is the bottom spring in the stack. With its forward extension to the left, it positions the sear toward the rear of the gun so that it may engage the hammer’s full cock notch. This spring is analogous to the trigger spring in the non-set trigger gun, with extensive modification. 2. Sear Kickoff Spring: This is the largest and heaviest of these three springs. From its middle position in the stack, it forces the kickoff forward to release the sear. The thickened, round leading edge is positioned with the round edge up, held there by the kickoff spring rest pin. 3. Sear Kickoff Catch Spring: The smallest of the three, it is on the top of the stack of springs, with its right sided upward curve, it keeps forward pressure on the sear kickoff catch, causing it to engage the sear kickoff when the trigger is moved forward, setting the trigger. Spring Screw: The three springs, one atop the other, are held in place to the tang by this screw that passes through holes in the back of each spring into the threaded tang hole. Sear Kickoff Spring Rest Pin: This pin holds the forward end of the kickoff spring down, assuring contact with the sear kickoff. The pin has a flat side that rests on the surface of the spring. While the set trigger option, introduced in 1873, seems to have had fewer orders over time, perhaps due to its somewhat delicate nature, it continued to be a part of many special order, fancy guns. It is not only found on 1873 models, but on some 1876s as well. In addition, it has been reported to be found on some model 1886 rifles and on rare occasions in an 1892 or 1894.x While it had its weakness and vulnerabilities, it also seems to have functioned properly much of the time. One can’t help but marvel at the ingenuity and craftsmanship of those early Winchester workers. Set triggers are still very desirable to Winchester collectors and understanding their strengths and weakness is important. It is likewise helpful to understand their operation as well as the proper disassembly and reassembly techniques to keep them in good working order. Books such as George Stone’s and internet web sites, such as Jim Grueter’s are excellent references for additional information on the Winchester model 1873 set trigger.
Page 38 Check Us Out at www.WinchesterCollector.org Three different lower tang configurations, shown at full cock Left: Standard trigger. The sear and hammer notches are the full width of the hammer. Center: Set trigger with the Center Sear Over‐ride. Note hammer notch is half the width and fly in the center. Right: Set trigger with Outside Sear Over‐ride. Note hammer notch less than half width, due to the milling of the left side of the hammer to allow the outside fly to move. Fly just visible on the outside of the hammer. Lower tang trigger mechanisms Upper Left: Standard trigger. Center: Set trigger with the Sear Kickoff Catch engaged with the Sear Kickoff. Lower Right: Set trigger with Sear Kickoff Catch in the unset position, behind the Sear Kickoff. The tapered Main Spring and stirrup, positioned to the left on the back of the hammer allows space for the kickoff and the kickoff catch to function. Set Trigger Adjustment Screw Note the small hole in addition to the slot. The hole is about .035 inches in diameter and is found on this Winchester rifle SN 27, manufactured and shipped in 1873. Note the asymmetric tang opening on the right rear of the trigger opening for the screw portion of the set trigger. Lower Tang and Main Spring Note the asymmetric trigger opening on the rear right for the trigger extension that holds the adjustment screw. The set trigger main spring is asymmetric to the left and tapered, to allow room for the Sear Kickoff and Catch to function unimpeded. Trigger with Adjusting Screw, Sear and Trigger Pin
Fall 2012 Page 39 Hammers with Sear Over‐rides Left: Center Sear Over‐ride. Right: Outside Sear Over‐ride. Note the stirrup attachment is on the left bottom of the hammer. Kickoff Catch, Pin and Kickoffs Top:Sear Kickoff Catch and Pin. Note two diameters of the Pin. Bottom: Two Sear Kickoffs. Left: note semi‐circular milling to allow for the Center Sear Over‐ ride fly. Right: Sear Kickoff for an Outside fly. The left side of the hammer is milled for the fly rather than the Kickoff. Three Springs, Spring Screw and the Kickoff Rest Pin Left to right: Sear Spring, Sear Kickoff Spring and Sear Kickoff Catch Spring. Note the flat central area on the Pin that rests on the surface of that spring. ___________________________________ i Williamson, Harold F. “Winchester – The Gun That Won The West”, A. S. Barnes and Company, South Brunswick and New York, 1952, p.67. ii Gordon, James D. “Winchester’s New Model of M1873 – A Tribute” , Vol. 1, James D. Gordon, Grant, Colorado, 1997, p.184. iii Pirkle, Arthur, “Winchester Lever Action Repeating Firearms, Vol. 1,North Cape Publications, Inc., 2002, pp. 71‐72. iv Gordon, James D., op. cit., p.184. v Stone, George W. “The Winchester M1873 Handbook”, Ron’s Guns, Inc., East Lyme, Connecticut, 1973. pp.101‐107. vi Stone, George W., op. cit., p.101. vii Gordon, James D., op. cit., pp.183‐184. viii Stone, George W., op. cit., p.103. ix Houze, Herbert G., Personal communication. x Grueter, Jim, tapaderaswinchesters.com. © Stephen W. Rutter, M.D. 2012
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