There is a fair bit of confusion about the Harrington & Richardson models 120 and 121 and the Sears J. C. Higgins Model 10 shotguns. There are a number of references with cross references that list sever of the early Model 10 variations as being Harrington & Richardson
Here is data from the Jack First and the Numrich Gun Parts catalogs.
Note that neither Numrich nor Jack First have complete listings of the Sears bolt action shotguns.
Note that some Numrich data on page 1179 contradicts their own data on page 1181
Note that both Numrich and Jack First list 583.20 as a pump shotgun model which is an error.
It is my opinion that most variations of these two catalogs form the basis for the other cross references that I have come across. The Blue Book dnd Brownells both credit Numrich for their crossover data.
The Harrington & Richardson shotgun Models 120 and 121 came in 16 and 20 Gauge where as the Sears Model 10 came in 12 , 16 and 20 gauge.
Early examples of the two brands do look alike externally right down to the style of rubber recoil pad. With the stock off there are some obvious differences. The Numrich parts picture of the models 120 and 121 are different from the High Standard shotgun. Specifically the lugs that are the mounting points for the magazine tube, the sear and the trigger are different from the High Standard shotguns. The H&R uses three attachment pieces while HS uses only two. There is a H&R patent that has an illustration that looks more like the High Standard than the pictures in the Numrich catalog
This patent is often cited as proof that H&R owned the design and the illustrations suggest that they are similar. However the patent if not for the shotgun design but for a feature for bolt action guns that automatically applies the safety whenever the bolt is cycled Since the Model 10 did not have this feature the patent is not really a persuasive argument.
The recoil pad for the first few years of the Model 10 and the H&R model do look alike. I would propose that both High Standard and H&R both bought the pads from the same vendor. I have removed the pad from my 583.1 and there is no name or any other identifying marks on the rubber. High Standard appears to have changed the recoil pad design with the introduction of the Sears Model 20 pump action shotgun beginning at 583.53.
My model 10, 583.1 has a stamped steel stock reinforcement which is covered by a Post war High Standard patent
High Standard began selling shotguns to the gun trade in 1940. The earliest ship date I have found is January 3, 1940 and the shipping records slit a large number of well known gun dealers and distributor. Sears was one of the customers but was not a significant percentage od the shipments. These gusn continued shipments during the war with the customers being a who’s who of the defense plants.- High Standard manufacturing C0( the machinegun company), A C Spark Division, Foot Brothers Gear, Ford Motor, Springfield Armory, Pontiac Cadillac International Harvester, Flannery Bolt, Guide, Lamp Ithaca, United States Treasury Frigidaire, L c Smith Corona, Buick, American Locomotive, Carrier, Auto-Ordnance, O. F. Mossberg, Bullard, Singer, Smith & Wesson, Remington Rand, Colt, Nash Kelvinator, Lycoming, Wright Aeronautical and many others. After the war, several of these war time customers continued buying these but the majority were being shipped to the normal commercial gun trade. High Standard was in a good position to reenter the shotgun market after the war.
These guns could well have been designed by High Standard’s owner Gus Swebilius without any input from H&R. Swebilius had risen from barrel driller to chief engineer for Marlin in the 1920’s and had several dozen gun design patents including rifles, and the Marlin aircraft machinegun and the synchronizer which allowed the machine gun to fire within the propeller arc without hitting the propeller. Later after founding High Standard he continued to work as a gun designer for Winchester up until the time High Standard received an large order for .50 caliber M-2 machineguns. Swebilius had done a lot of pump and semi-auto shotgun experimental designs
The High Standard designation for the Model 10 sold to Sears was BA-1 and there are roll marks in the log that shows that Sears was not the only customer. This is different from the Model 20 which Sears commissioned High Standard to design develop and manufacture exclusively for Sears. High Standard did not sell any guns designed for Sears at Sears expense until 1960. In my opinion, the fact that the BA-1 was sold to multiple customers suggests that Sears did not in fact own that design.
The Sears identification numbers 583.1 and higher are composed like the other identification number of the vendor number (583 is for High Standard) and the rest of the number defines the model and variation of of that model. Several have argued that 583 was an in house number buth that flies in the face if the fact that there were several revolvers and a pistok with 583 designations which were not sears owned designs nor were they exclusive for sears. High Standard began selling the police style revolver at the same time as Sears and the Western design revolvers and the Dura-Matic was dold by High Standard before they were offered to Sears.
Another fallacy related to the Sears model 10 is the recall of this model, Sears was apparently confused as to just what to recall since they stated that they were recalling 12 Gauge Model 10’s and the n they list Sears identification number that include all three gauges but they omitted the 583.17A.
Several people on the gun forums say that the guns are safe and that the problem occurs when the owner does not properly tighten the bolt retention screw and when the screw falls out, the bolt can be pulled back into the shooter’s face. That certainly is a plausible story and probably did happen more than once.
However, the real problem has to do with the receiver failing such that the part of the receiver that provides the recoil support to the primary locking ( the base of the bolt handle) cracks and the secondary locking lug is not sufficient to stand the load of the firing shell. I have from the High Standard records photos of these failures and it is not a pretty sight. The photos clearly show the failed receiver and failed secondary locking lug.
I would love to discuss any primary evidence that contradicts what I have said above. Although this is what I believe today , research is never done and all I want is the true and correct story.