Richardson  Receivers



The receiver pictured below is a Richardson Ultimax™.  This particular receiver is an early Colt style with optional (extra cost)

square end actuator slot, early Colt markings and a serial number.



I made my first Thompson receiver in 1957. I was working as a machinist while earning a degree in mechanical engineering at the University of Illinois, Champaign/Urbana campus. After graduating with a BSME, I went to work as an aerospace engineer but I never stopped working on the Thompson guns. It was my original intention to put the Thompson back into production. I formed the Universal Precision Corporation to do just that but never got beyond making half size Thompsons which were featured in several magazine articles. It was Ronald Reagan who put an end to that dream by outlawing the sale of new-made machine guns. However, that and the availability of parts kits opened the door to a demand for semi-finished receivers anyone could buy. I do not use the term "80%" because it  has no legal meaning nor does it accurately reflect the percentage of completion. It is another company's trade name.  Nor do I use the term "dummy" which is usually used to refer to some cheap chunk of metal or plastic that simply provides a platform on which to attach a few gun parts.

My Thompson receivers are made from steel bars having the same alloy, hardness and tensile strength used in the original guns. Also, the steel is stress relieved to prevent twisting during machining. This steel has alloying elements that make it easy to machine and produce a smooth finish. The bars are machined on fully automatic, computer controlled machining centers. Computer controlled machining enables edge radii to completely follow the front end contours and to properly radius the 1921-1928A1 drum slots and magazine cavity edges.  Every detail is given the utmost attention including such things as the ejection port bevel and the timing of the ejector threads to assure proper wind-up of the ejector into the receiver.   Centerline coordinate machining is used with one set-up for all four sides, edge radii and interior in order to eliminate tolerance and error cumulations caused by changing set-ups and reference lines. The quality of these receivers exceeds the originals made by Colt, Savage or the real Auto-Ordnance Corporation (Bridgeport) or anyone else. 

All Thompson Submachine Gun receivers are of one of two types. I call them "Type 2" and "Type M". Type 2 receivers are characterized by having a rectangular mid-area cross section and slots in the magazine well to accept a drum magazine. Original Thompson Models 1921, 1922, 1923, 1927, 1928 and 1928A1 are all Type 2 receivers and are dimensionally identical. For manufacturing purposes, I refer to these receivers as "Model 2A". Type M receivers are characterized by having a hat-shaped mid-area cross section and no provisions for a drum magazine. Original Thompson Models M1 and M1A1 are Type M receivers and are dimensionally identical. For manufacturing purposes, I refer to these receivers as "Model MA". Original receivers are available in blued steel only.   My use of "A" to designate my original configuration receivers is in keeping with "A" being  used by the Auto-Ordnance Corporation to designate their original Thompson configuration starting in 1927.  AOC never did come out with a "B" configuration as I have done as shown below.

I manufacture several receivers for the Thompson which are variations of the original "A" receivers. They are also categorized as Types 2 or M. These special design receivers all feature, what I consider to be, improvements over the original designs. Those improvements include the frame rails being extended all the way to the rear end of the receiver for added strength, rounded corners on the extractor slot and provisions to enable the receiver to accept the Richardson Screw-On Grip Mount. That mount can be removed BEFORE the barrel is removed or installed which makes barreling much easier.  I call these special design receivers "Improved" or "B" receivers. Two improvements that I have wanted to incorporate are the 3-flat rear end design of the M1 on Type 2 receivers, which would improve rear end strength. I would also like to change the barrel threads from the ridiculous .850'-10 square to .850"-20 V-threads. The problem with that is that new barrels would be required. That might be the way to go on my semi-auto design. However, I do not think there would be enough demand for those changes at this time to justify inventorying such receivers. But if you agree with me and can fit either or both changes into a receiver for yourself, I will accept a custom order at no extra charge. Improved ("B") and special receivers are available in either blued steel or natural aluminum.

All Richardson receivers, except for the earliest ones, are trade marked with the letter "R" at the front of the receiver on the bottom of the grip mount slot for identification. This is important because receivers made by others have often been claimed to be Richardson receivers by resellers.

In the past I have offered three levels of receivers: "Gun", "Display" and "Ultimax™". Gun receivers are fully functional Thompson Submachine Gun receivers. I used to make those for a movie prop shop under their license. The most notable one I made was the 1921 Dillinger gun for that movie. Because of changes in Government regulations, I can no longer make them without getting my own license. There is simply not enough demand for functional Thompson receivers to justify the expense and hassle involved. For years my "Display" receivers were very popular as semi-finished receivers, but people kept asking for more and more of the detail work to be done, especially in the bolt channel area, so I came up with the Ultimax™ concept. I thought maybe 5% of my customers would be willing to pay the extra cost of the Ultimax™ receiver. I could not have been more wrong. After I introduced the Ultimax™, that was what everyone wanted. The extremely favorable response to the introduction of the Richardson Ultmax™ receiver concept has resulted in my decision to manufacture only Ultimax™ receivers starting with the 2017 production.



The Ultimax™ is a semi-finished receiver with every Thompson gun receiver machine operation completed or substantially completed. The front and back ends of the bolt channel are finished, including the expanded rear section of the 1921-1928A1 receivers that accommodates the oiler. The breech entry chamfer is finished. Lock ramps and bevels are finished as applicable. The ejection port bevel is finished. Sight fastener holes are threaded for special sight screws. Screws can be used while the receiver is configured as a display and later the threads can easily be drilled out and countersunk to accept original Thompson rivets. As an alternative, the screw fastening can be retained but care must be taken to grind off any screw intrusion into the bolt channel.

The Ultimax™ is a complete and finished Thompson receiver except that there is a solid section in the middle of the bolt channel. Prior to Ultimax™, any machining operation in the bolt channel which could not be completed was not done at all. Those operations would be left for the person finishing the receiver. That required the finisher to make complicated calculations and set-ups in accordance with the manufacturing drawings. Ultimax™ changed all that by having every machining operation done at least partially. To do that, Ultimax™ introduced the concept of "interrupted cutter path machining". This means that a cut that normally starts at one end of the bolt channel and terminates at the other end will be started and stopped as it normally would be in a working Thompson receiver. It is only in the solid middle section that the cut has been i"nterrupted". This makes it very simple to determine what is missing and what needs to be done without the use of drawings or calculations.

The width of the bolt channel is made slightly undersized to allow for a final finish cut to create smooth full length bolt channel side walls. No Ultimax™ receiver can accept a bolt because of the solid section left in the middle of the bolt channel and the narrower channel width.

Features common to all Ultimax™ receivers include the front pocketed portion of the bolt channel extended to the rear far enough to clear the bolt handle hole and slot. That allows the use of a new design Display Bolt Handle Kit which clamps anywhere along the bolt handle slot. The display bolt handle can be positioned at the front or rear end of the slot in order to emulate "closed-bolt" or "cocked-bolt" handle positions. Provisions are also included to enable a new simplified design Display Pilot Kit to be fitted. All Ultimax™ receivers provide clearance so that the frame components can function normally.

Those who have the license to finish a semi-finished receiver into a working gun will find the Ultimax™ to be the best receiver available for that purpose. All of the time consuming and difficult machining set-ups and operations have been eliminated or completed. Finishing the Ultimax™ receiver requires removing the solid middle section and finishing the side walls of the bolt channel. 1921 style receivers (Type 2) also require completing the side tracks or lightening slots. But what needs to be done is obvious since every interrupted cut starts and stops as it would normally. It is not necessary to analyze drawings to set cutter positions - just continue the interrupted cuts using the beginning and ending areas as guides. Those building a display gun with an Ultimax™ receiver have the added enjoyment of understanding how their "gun" was designed to work - it’s all there!

Only one cutter is required to finish a Type M (M1 style) Ultimax™ receiver. It is a 1/2"diameter, 4 flute, 1-3/8" cutting length, .031" corner radius, ALTiN coated, carbide end mill. Type 2 (1921-style) Ultimax™ receivers require the same cutter plus a special 1" diameter x 1/4" wide x .031" bottom corner radius, M42, ALTiN coated, long neck, T-slot cutter to cut the side slots. These are the recommended cutters and are special cutters custom made for Richardson. Therefore, they are offered on the TOOLS page of this website. Other types of cutters may be made to work if the recommended cutters are not available.



Model 2A: This is the original receiver as made by Colt, Savage and Auto-Ordnance. All Colt and 1928 Savage receivers will be Model 2As because of the classic status of those guns.  Blued steel, $885.

Model 2B: This is the improved version of the Model 2A. The Model 2B receiver is my redesign of the 1921-1928A1 receivers. The pilot hole is sized like an M1 but remains in the 1921-1928A1 position. The actuator slot is positioned slightly rearward to eliminate the excessive handle slot opening. This receiver is designed to be finished to accept a 1921 or 1928 bolt/actuator/lock assembly but eliminates the oiler which, arguably, never really worked and severely weakened the receiver. A modified M1 pilot and modified M1 buffer or Richardson #2B Pilot and #2B Urethane Buffer are required. In my opinion, this creates the ultimate Type 2 gun because it has all the benefits of the 1921 lock/actuator mechanism with the ease of assembly of the M1 gun. This receiver is very strong. Blued steel, $845. Natural aluminum $865.

Model 2M: This receiver is identical to the Model 2B except that it does not have lock ramps and the pilot hole is in the M1 position. It is designed to be fitted with the Richardson M2 Bolt Assembly or an M1 or M1A1 bolt fitted with a top mounted handle. It is meant for those who wish to make a Type 2 gun with a minimum of time and cost and the "slam fire" simplicity of the M1A1 bolt assembly. It was originally designed as a movie gun but its configuration has made it popular with re-enactors and shooters. Blued steel, $730. Natural aluminum, $750.



Model MA: This is the original receiver as made by Savage and Auto-Ordnance during WW2 for the U.S. Army. Blued steel, $685.

Model MB: This is the improved version of the Model MA. Blued steel, $665. Natural aluminum, $685.

Model M2: The M2 is my redesign of the M1 and M1A1 receivers. The bolt handle slot is located on the top like the 1921. The pilot hole is sized like an M1 and located in the M1 position. It uses a Richardson M2 Bolt Assembly or an M1 or M1A1 bolt fitted with a top mounted handle. The upper sides of the receiver are continued forward to the front end to produce a sleeker looking receiver. The nose of the receiver is relieved on the sides below the barrel area, similar to the nose profile on the 1911 Colt auto-pistol, to better match both horizontal forearms and vertical foregrips. It is available with the top side edges non-rounded in the rear sight area in order to accept a Lyman or Richardson adjustable rear sight. I designed this receiver before the 1986 law which prohibited people from acquiring new-made machine guns. It was designed to be made in large quantities from an extrusion in order to make it affordable to everyone. It is interchangeable with any Type M machine gun receiver. Blued steel, $665. Natural aluminum, $685.

Model M3: This receiver is identical to the Model MB except that the bolt handle is on the left side. Blued steel, $665. Natural aluminum, $685.

Tanker Models: Any improved, steel, Type M receiver can be ordered as a "Tanker" model at no extra charge. The "Tanker" has provisions to accept an UZI standard SMG folding stock. A special Richardson steel frame is required which is not yet available. A modified M1 frame can be used.

Paratrooper Models: Any improved, aluminum, Type M receiver can be ordered as a "Paratrooper" model at no extra charge. The "Paratrooper" has provisions to accept an UZI standard SMG folding stock. A special Richardson aluminum frame is required which is not yet available.



Receiver prices do not include markings which will vary depending on the receiver model. Both minimal generic markings and full original rolled markings are available as are serial numbers. Refer to the "MARKINGS" section below for details.


NOTE:  The Display Bolt Handle Kits and Display Pilot Kits shown below have been replaced with new models applicable to 2017 receiver production.  Use this for reference until new catalog pages are created.


Screw-On Grip Mount

The photo shows my Screw-On Grip Mount both mounted on a receiver (top photo) and unmounted (bottom photo).  Note that the barrel is shown installed in both cases.  That is the advantage of my design.  The barrel does not have to be removed in order to remove the Grip Mount.  In fact, the first thing to do when removing or installing a barrel is to remove the Screw-On Grip Mount from the receiver.  This tremendously simplifies barreling and eliminates the force applied to the middle of the barrel by the standard TSMG grip mount during shooting.   To use this Grip Mount, the receiver has to be specially made.  All my special receivers (22, 2M, 2S, MB, M2 , M3 & MS) accept the Screw-On Grip Mount and will not accept a standard TSMG grip mount.  A standard TSMG receiver can not be made to accept the Screw-On Grip Mount. 


NOTE: The following will be revised to correct model references.







1928 Savage Aluminum Receivers

In 1941 the Savage Arms Company manufactured a number of 1928 receivers in aluminum for the British.  Nothing came of it because the U.S. entered the war and took over all Thompson production.  These receivers are an authentic reproduction.  The price is $45 over the price of the same receivers in steel. 

M2 Receiver With M1 Style Rear End And Bolt Handle Slots On Top And Right Side

M1 Receiver With Additional Bolt Handle Slot On The Left Side.  At Least One Receiver Like This Was Made By Savage.  Seems Like This Would Have Been A Good Idea Because It Allows The Shooter To Choose To Fit The Bolt Handle To Either The Right Or Left Side.

M2 Receiver With M1 Rear End And Fitted With Richardson Display Bolt Handle Kit, Display Pilot Kit And Richardson Combo Rear Sight.

2S (Semi-Auto) Receiver

1928 Savage Aluminum Receiver.  A Number Of  Guns With Aluminum Receivers And Frames And Plastic "Wood" Parts Were Made By Savage In 1941 For British Testing.

RIGHT SIDE 1928 Savage Aluminum Receiver.  A Number Of  Guns With Aluminum Receivers And Frames And Plastic "Wood" Parts Were Made By Savage In 1941 For British Testing






1928 Savage ESF  Receiver

This receiver has the optional cost markings, serial number, Display Knurled 1928 Bolt Handle and Display 1928 Pilot.  The 1928 Savage is interesting because it is the only 1928 not made by modifying a 1921 and was used by the British Commonwealth countries and France.  It was always fitted with a vertical foregrip.  This is not a U.S. Army model.


TSMG parts kits generally consist of all parts of the gun except the receiver. Kits now being supplied often have no barrel or are provided with an inferior aftermarket barrel. However, unlike the other assemblies in the kits, the barrel assembly can not be readily disassembled. Even in the best condition, this assembly requires tools and skill to take it apart. Add 65 years, rust, powder residue and maybe a phosphate (Parkerizing) refinish without the barrel assembly having been taken apart, the task becomes more difficult. And because the grip mount can not be removed before the barrel has been unscrewed, gripping the barrel is difficult, The front sight or compensator must be removed from the barrel and re-installed because it will usually not end up in the vertical position once the barrel has been fitted to a new receiver. For those wishing to avoid all this work, I offer complete barreled receiver assemblies. The price is the sum of the parts. I have discontinued using 3-piece grip mounts and am now only fitting 1-piece grip mounts or my Screw-On Grip Mounts, as applicable.. A receiver, grip mount and barrel must be ordered to create a complete barreled assembly. In the case of compensator or standard front sight, I do not pin either because I do not think it is necessary, the cost is increased significantly and pinning makes it much more difficult to replace the barrel in the future. Add $50 labor charge for barreling. Since I do no custom gun work, I will not fit your kit parts onto a receive


1) Late 1921A Colt: $1641 ($36 HIS)
Price includes late “Colt” pre-Ultimax receiver with 4th pattern markings, Richardson barrel, TSMG 1-piece grip mount, front sight, Display Bolt Handle, Display Pilot and “Colt” ejector.

2) Early WW2 1928A1: $1451 ($36 HIS)
Price includes pre-Ultimax receiver with WW2 1928A1 markings, Richardson finned barrel, TSMG 1-piece grip mount, Display Bolt Handle and Display Pilot.

3) M1A1: $1305 ($36 HIS)
Price includes pre-Ultimax receiver with M1A1 markings, new WW2 surplus barrel, TSMG 1-piece grip mount, Display Bolt Handle, Display Pilot and front sight.


Colt Receivers Fitted With 1921A Barrels And Richardson Early Style Compensators

1928 Savage Barreled Aluminum Receiver

This receiver is fitted with an early Savage type flat 1-piece ejector, Display Bolt Handle Kit and Display Pilot Kit.  Note that this is an Ultimax Plus receiver which allows the bolt handle to be located any where along the bolt handle slot to simulate an open or closed bolt.

1921 Colt Barreled Receiver

The barreled receiver shown consists of a Richardson 1921 "Colt" ESF receiver with 1st Pattern Colt markings, Richardson 1921 Barrel and Richardson 1921 Front Sight.  Only the grip mount is original. 

 Two WWII 1928A1 Ultimax Barreled Receivers 

MS (Semi-Auto) Receiver Fitted With M1 TSMG Barrel And Front Sight And Richardson Screw-On Grip Mount


Early Colt Barreled Receiver Featuring Richardson 1st Configuration 1921 Ultimax Receiver, 1st 1921 Pattern Markings, Colt-Style Ejector; Richardson Barrel, Sight, 1921 Display Bolt Handle & Pilot.



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