Unblinking Eye
The Remington Model 51
David Rachwal - Handguns of the World

The Remington Model 51

by Ed Buffaloe


Remington Model 51 right sideThe Remington Model 51 was designed by John D. Pedersen prior to the First World War.  The first patent application on the gun was filed in 1915.  In 1920, seven patents were issued for the weapon.  Six went to John Pedersen, and one went to Crawford C. Loomis, both employees of the Remington Arms Company.  Between 1921 and 1926, an additional 25 patents were granted for various aspects of the gun’s mechanism, most to Pedersen.  Many of the patented mechanisms were never utilized in a production gun.

One has only to hold the Remington 51 to feel its quality.  The first thing you notice is how well the grip fits your hand--the result of extensive testing with hand molds to determine the correct size and shape for the average hand.  Similar effort went into calculating the correct grip angle to allow the gun to point naturally.  Very few guns feel so much like an extension of the hand as does the Remington 51.  W.H. B. Smith says:  “With the sole exception of the Luger, and the new German Walther P38, the Walther PPK, Sauer-38 and Mauser HSc (all foreign developments) this Remington 51 is probably the best-balanced, most-instinctive-pointing pistol ever made.”  Some of the Remington advertising went so far as to describe the pistol as “self aiming.”  R.K. Wilson says the Remington 51 is “...in the opinion of many authorities, the best pocket self-loading pistol ever designed...”

The gun has three safeties:  a thumb-operated safety, a grip safety, and a magazine safety.  The grip safety locks the disconnector, locks the sear in the hammer notch, locks the slide, and serves two additional functions.  Since the grip safety does not pop out unless the gun is cocked, it acts as a cocked weapon indicator.  It also serves as a lock open device for the slide if it is engaged when the slide is retracted.  Squeezing the grip safety with the slide locked open will cause the slide to close and, if a full magazine has been previously inserted, a round will be chambered.  The thumb safety cannot be engaged unless the hammer is cocked, and when in the safe position it locks the grip safety so it cannot be disengaged.

Interestingly enough, the thumb safety does not appear on the original patent drawings, though it does appear on all the known prototypes.  Remington advertised that the gun could be carried safely with only the grip safety in operation, but the thumb safety could be utilized by those who preferred a more positive lock.  The Model 51 also has a magazine safety which prevents it from being fired when the magazine is not inserted.  The magazine safety does not appear on any of the known prototypes.

Remington Model 51 left sideThe unique locking mechanism of the Remington 51 is rather difficult to describe in words.  It has been labeled as a “momentum block” system and as a “blowback/recoil” system, in an effort to differentiate it from a simple blowback action, a delayed blowback action, or a standard locked recoil action.  R.K. Wilson considered it a type of delayed blowback mechanism, and that seems reasonable to me, though others may certainly disagree.  The Remington U.M.C. company, in one of its advertising brochures, stated: “Breech remains positively locked until bullet has left the muzzle--not a blow-back action.”

The gun consists of the usual receiver and slide components, but the breech block is separate.  Sometimes the breech block is referred to as being in two parts, the rearmost portion that supports the rear of the firing pin being integral with the slide.  But the moveable portion is independent of both slide and receiver, and since it contains the firing pin, firing pin spring, and the extractor it is usually referred to as the breech block.  When recoil begins, the slide moves toward the rear.  The breach block remains against the back of the cartridge until the slide moves backward approximately 0.083 inches.  The slide continues its rearward motion for a further 0.2 inches, whereupon the moveable portion of the breech block is lifted out of engagement with the receiver and effectively becomes part of the slide as it recoils.  The cartridge is ejected in the usual manner; a new round is stripped from the magazine and chambered by the returning slide.  An advantage of Pedersen’s moveable breech block design is that it allows for a lighter slide than a straight blowback operated pistol, and hence an overall lighter weapon.

The .45 Caliber M53

Remington wanted a piece of the military market, but were informed by the U.S. Army that any gun submitted would have to be chambered for the .45 auto cartridge.  So in 1917 they developed a .45 version of Pedersen’s design, which was designated the Model 53.  The pistol was an enlarged version of the Model 51, with an external hammer, a slide lock/release lever, and no safeties.   When informed that the pistol was ready for testing, the Army responded ambivalently.  They placed an order for 150,000 Model 1911s from Remington, and informed them that they would test the new pistol if submitted.  Remington took the order for the 1911s as a silent rejection of their M53 and never followed up with the Army.  However, a group of Navy and Marine officers visited the Remington factory on 4 April 1918 and indicated that since they were unable to obtain sufficient quantities of the Model 1911 to meet their requirements they were interested in examining the M53.

Subsequently, the Navy ran extensive tests on the M53 and concluded it was “...a simple, rugged and entirely dependable weapon, which should be suitable in every respect for a service pistol.”  It was lighter and more accurate than the Government Model Colt, with less recoil and fewer moving parts.  The Navy was ready to replace all their then-current handguns with the M53, and requested a bid from Remington for 75,000 pistols.  Remington submitted a bid on 21 June 1918 and when that bid was rejected as too high they submitted another on 5 July 1919.  But, with the end of the First World War in late 1918, military priorities had changed and a contract was never finalized.  Remington needed nearly half a million dollars to tool up for production and the Navy couldn’t justify the expenditure after the war, even though the cost per gun was substantially less than for the Colt 1911.

The Army Infantry and Cavalry Board finally examined the Remington M53 on 23 February 1920, having read the positive report written by the Navy Department.  The Board specifically asked if the gun could be cocked and fired one-handed by a mounted soldier while holding his horse’s reins in the other hand.  Crawford Loomis of Remington demonstrated that it could be, with no greater difficulty than the Colt.  However, the gun was never tested by the Army, and no further interest was ever evinced.

Ezell’s Handguns of the World has a photograph of one of the original M53 prototypes (labeled the Remington Model 1917) that clearly shows the gun’s external hammer.  The gun displays a slide lock/release lever on the left side.  (There is also a photograph of the gun in Hatcher’s Notebook and several photographs in Meadows’ book, U.S. Military Automatic Pistols.)

Remington introduced the Model 51 for the civilian market in late 1918, and ramped up to full production in 1919.  Production declined steadily in succeeding years and ended in 1927--though approximately fifty-one .380s and ten .32s were assembled from remaining parts between 1928 and 1934.  Approximately 64,796 Model 51s were made: 54,518 in .380 caliber, and 10,278 in .32.  The .380 wes designated the “Series of 1918.”  The .32 version didn’t appear until 1921 and so was designated the “Series of 1921.”  The .32 version was intended primarily for European consumption, where the .380 round was scarce.  One source states that the early .32s were special-order-only in the U.S.  The specimen shown in most of my photographs is the more common .380 version, with the early 9 slide serrations, but with the Remington Trade Mark stamp on the right side.  The year of manufacture was 1921.  For other photographs of Remington 51 variants, see my article Highlights from the J.B. Cargile Collection of Remington 51s.

Patton’s Remington 51

In late 1943 Major General Kenyon A. Joyce visited Patton at his headquarters in Sicily.  He saw that Patton was wearing a revolver and suggested he should have an automatic pistol.  Joyce tried to get his brother-in-law to obtain a Remington 51 and send it to him to give to Patton, but apparently the brother-in-law was unable to locate one.  So when Joyce returned to the U.S. he contacted Roy C. Swan of Remington to see if he could obtain one.  Swan located a used one in Denver and had it refurbished at the Remington Factory.  The gun was engraved “To George Patton / From his shooting partner of many years / Kenyon Joyce.”

                             --from Patton and His Pistols.

W.H.B. Smith states that the Model 51’s  “... manufacture was discontinued, because the introduction of firearms laws made manufacture economically unsound.”  He is referring to the National Firearms act of 1934, which forced pistol and machine gun manufacturers to register and pay a tax on all sales.  But economic factors were involved as well.  Production actually ended in 1927.  Sales of the Model 51 had never been robust, and after the market crash of 1929, hardly anyone in the U.S. could afford to buy guns.  Revolvers were still considered the most reliable handguns by many shooters.  In the U.S. only Colt continued to manufacture automatics after 1929.

By 1932 Remington was losing as much as one million dollars per year, and in 1933 E.I. du Pont de Nemours & Company purchased a controlling interest in Remington and reorganized the company.  This reorganization resulted in the elimination of any products that were unprofitable.  The unprofitable Model 51 was never revived.  At the end of 1934 Remington posted a modest profit of $142,589, and by 1936 the company stock was paying dividends again.  But Remington did not manufacture another handgun until 1963 (the XP-100 single-shot).

The Model 51 is sometimes described as overly complex for the relatively low power cartridges it uses, for which simpler blowback designs will suffice, though it has fewer moving parts than the Colt Government Model of 1911, which is a true locked breech weapon.  The so-called “momentum block” mechanism of the Model 51 reduces felt recoil and makes the gun lighter, more accurate, and easier to shoot.  A quick look at the drawing of the moveable breech block on the Model 51 will give an idea of the complex machining required to manufacture it and the slide with which it mates.  Despite its complexity, the gun sold for a mere $15.75 at a time when the Colt Pocket Model cost $20.50.  Remington had underpriced the gun in an effort to gain market share.

Type I Old style serrations
Type II new style serrations
Anchor proof
Sun proof
J.B. Wood states that the most stressed parts of the Model 51 are the moveable breech block and the barrel lock pin.  The moveable portion of the breach block is “extensively skeletonized for passage of the firing pin, the extractor recess, and various locking surfaces,” and in rare cases is subject to stress cracks.  Likewise, the barrel lock pin is not particularly robust, but a new one can be easily machined.  Wood states that the early Model 51 had an extractor with a tempered spring tail, whereas later it was changed “to an extractor with no spring, cammed into operation by the movement of the internal breech block.”  In reality, the springless extractors were used only on the .32s, and the .380s all had spring extractors.  Replacement parts have been scarce for many years.

All Model 51s are marked with a serial number on the left side of the frame, with the prefix “PA” for Pedersen Automatic.  The early .380 Model 51s had 9 vertical serrations--wide and U shaped--on the rear of the slide.  There were no markings on the right side, and no caliber designation (except on the magazine).  At some point, the Remington trade mark was added on the right side of the receiver, and slides were given 15 narrow, sawtooth serrations.  Most Model 51s will have a small anchor stamped on the right side of the trigger guard, inside the slide in the hammer well, and inside the frame just below where the barrel sits--these are inspection stamps.  A very few have a sun instead of an anchor--these are rare.  (Supposedly the sun stamp was used in 1922 and 1923.  However, my gun which was made in 1921 has both the sun and anchor stamps inside the frame beneath the barrel.)

On the top of the slide, partially obscured by the fine lines cut to reduce glare, are the words “THE REMINGTON ARMS-UNION METALLIC CARTRIDGE CO., INC.  REMINGTON ILION WKS. ILION, N.Y. U.S.A.  PEDERSEN’S PATENTS PENDING.”  Very late issue guns are stamped “REMINGTON ARMS COMPANY, INC. ILION WKS. N.Y. U.S.A. PEDERSEN PATENT/PAT’D . MAR.9 20, AUG.3 20, OCT.12 20, JUNE 14 21 OTHERS PENDING.”  Some time before the .32 version appeared, the cartridge size was stamped on the outer chamber, visible on the right side of the gun, so the two guns could be easily distinguished.  Late model .32s were stamped  32 CAL over 7.62 M/M.  Guns assembled from 1923 on were marked with two stamped capital letters on the left side trigger guard--these are Remington date stamps.  The first letter is for the month and the second for the year.  The Remington Society has a page that explicates these date codes.

Types of Remington 51 .380

Type I



9 slide serrations, no caliber marked on barrel, no Remington logo

Type II



15 slide serrations, .380 caliber marked on barrel, has Remington logo on right side

Types of Remington 51 .32

Type I



15 slide serrations, .32 stamped on barrel

Type II



15 slide serrations, .32 over 7.65mm stamped on barrel, s/n begins with 6 or 7

Type III



15 slide serrations, .32 over 7.65 on barrel, s/n begins with 9


  1. Retract the slide
    Remove the pin
    Lift the breach block
    Remove the breach block
    Remove barrel
    Depress the disconnector
    Remove the magazine.
  2. Retract the slide fully to cock the gun (and make sure the chamber is empty).
  3. With the grip safety depressed, hold the slide back about one-quarter inch to align the half-moon cutout on the left side of the slide with the barrel pin.  Poke the end of the barrel pin on the right side, to raise the head of the pin on the left side.  Remove the pin with a small screwdriver or the toe of the magazine base plate.
  4. Pull the slide back about three-quarters of an inch and grasp the end of the barrel (which has serrations to assist gripping it).  Depress the grip safety and pull the slide and barrel assembly off the receiver.
  5. Pull the barrel forward about a half-inch against the tension of the recoil spring and rotate the barrel lug toward the left, locking the barrel into a recess in the slide.  (The barrel can be cleaned in this position, if you don’t wish to disassemble the gun further.)
  6. Press the moveable breech block backward against the tension of the firing pin spring and lift up at its rear (you may need something to pry it up).  With the rear of the block lifted up, you can move the breech block forward and remove it from the slide.  (The extractor may fall out on the .32 models--there is no spring.)
  7. Tip the slide so the firing pin and its spring can drop out the end of the barrel.
  8. Pull the barrel forward against the tension of the recoil spring.  You will see there is a recess in the slide that is the exact size of the recoil spring bushing.  Tilt the barrel up and catch the bushing against the rear of this recess, then slide the barrel backward and lift it up and out of the slide, followed by the bushing and recoil spring.  You may have to pull the bushing back toward the front of the slide a little to free it.


  1. Insert the recoil spring and bushing into the slide and tilt the bushing up a little so it catches on the slide recess.
  2. Insert the barrel and push it toward the front of the slide, compressing the recoil spring and bushing, and snap it into place in the slide.  (You may have to compress the spring and bushing by hand to get them to snap into place.)
  3. Pull the barrel forward about a half-inch against the tension of the recoil spring and tilt the barrel lug toward the left, locking the barrel into its recess in the slide.
  4. Insert the firing pin and spring into the fixed part of the breech that is attached to the slide.
  5. Hook the fore part of the moveable breech block over the front of the firing pin spring and pull it backward and down at the rear until it snaps into place in the slide.
  6. Unhook the barrel from its recess, slide it back against the breech block, and make sure the barrel lug is centered properly.
  7. Align the slide on the forward end of the receiver and install it on its rails.  Push it back until it is stopped by the disconnector, which projects upward just behind the magazine well.  You may encounter some resistance, but this is normal.  You may have to depress the moveable ejector to get it out of the way.
  8. Depress the grip safety, push the disconnector down, and press the slide back until it locks onto the receiver.
  9. Hold the slide back about one-quarter inch to align the half-moon cutout on the left side of the slide with the hole in the receiver and insert the pin that holds the barrel in place.
  10. Replace the magazine.

Grip Removal

  1. On the side from which you wish to remove the grip, drift the retention pin flush with the frame.
  2. Push the grip down until it stops.
  3. Grasp the portion of the grip plate that is now beneath the bottom edge of the frame and lift it up, raising the rear edge first.

Seven shot groups at ten yards.

The Remington 51 and the Browning 1910
When I take the Remington to the range, it functions flawlessly with hardball ammunition, and and will even feed certain hollow points, particularly the Remington Golden Saber ammo.  The trigger pull is relatively heavy.  With concentration, I can fire 2 inch groups at 10 yards pretty consistently.  According to Don Simmons, later production guns had better trigger releases.  The gun is very slim and light, and is reliable enough for concealed carry.  It is perfectly safe to carry with a round in the chamber--one of its original selling points.  The heavy trigger can be an advantage in a concealed carry gun, since you won’t be likely to shoot someone accidentally.  Other than the trigger, the only major criticism I can level at the Remington is that the breech does not lock open on the last round.  I wish the M51 had a slide lock/release lever like the M53.

The Model 51 is a great gun to practice instinctive shooting with.  I find I can hit cans at ten feet with offhand shots about 80% of the time.  Field stripping seems complex on the face of it, but goes quickly with a little practice.  The toe of the magazine base can be used to punch out the pin from the right side, then pry it up from the left, and can also be used to remove the grips, so complete disassembly is possible with no tools.  The thumb safety is slow to disengage and impractical for defensive use, but probably unnecessary.  If you grip the gun firmly and pull the trigger with intent, it will shoot, but otherwise not.  That strikes me as just right.

Comparisons with the 1910 FN Browning are inevitable.  There are strong stylistic influences from the Browning, but altogether the Remington is more refined.  The Remington is slightly larger in length and height.  The Remington’s grip fills the hand, whereas with the Browning your little finger has to curl around the bottom.  The Remington is a little more slim than the Browning.  Both guns are extremely reliable.  Browning’s design has the merit of simplicity, and my .32 Browning Model 1910 is easily as accurate the Remington.  The Browning is a straight blowback design.  Its trigger isn’t great, but is better than the Remington.  Neither gun stays open on the last round, but at least the Remington has a means of locking the slide open when necessary.  Also, the Remington has a thumb-operated magazine release on the left-side grip, which is much faster than the one on the base of the Browning.  Finally, the Browning’s safety is not as robust as that of the Remington.

To sum up, the Remington is safe, reliable, accurate, ergonomic, and easy to carry, but has a less-than-great trigger and does not stay open on the last round fired.  The Model 51 was many years ahead of its time.  I wish someone would take up production of this fine pistol today. 


1910 Browning

Remington Model 51


7.65mm / .32 ACP

9mm Kurz / .380 ACP

Magazine Capacity

7 rounds

7 rounds*

Overall Length

6 inches / 153mm

6.38 inches / 162mm

Overall Height

3.91 inches / 99.4mm

4.67 inches / 118.5mm

Grip Depth at Base

1.67 inches / 42.4mm

1.99 inches / 50.6mm

Barrel Length

3.44 inches / 87.5mm

3.5 inches / 88.9mm

Slide Width

.8 inches / 20.3mm

.79 inches / 20mm

Weight Empty

19.6 ounces / 554.8g

20.7 ounces / 586g

* The .32 version of the Remington Model 51 holds 8 rounds.


American Rifleman, May 1986.  “General Patton’s Peacemaker,” by Ronald A. Ogan.
Complete Guide to Compact Handguns, by Gene Gangarosa, Jr.  Stoeger Publishing, Wayne, N.J.: 1997.
Firearms Assembly II, The NRA Guidebook to Handguns, National Rifle Association:  1975.
Handguns of the World, by Edward C. Ezell.  Barnes & Noble, New York:  1981.
The NRA Book of Small Arms, Volume I:  Pistols and Revolvers, by Walter H.B. Smith, 2nd Edition,
copublished by the NRA and The Military Service Publishing Co., Harrisburg, PA:  1948.
Patton and His Pistols, by Milton F. Perry and Barbara W. Parke.  Stackpole:  1957.
Remington Arms, An American History, by Alden Hatch.  Rinehart & Co., New York:  1956.
Remington Handguns, 2nd Edition, Charles Lee Karr, Jr. and Caroll Robbins Karr,
The Stackpole Company, Harrisburg, PA: 1951.
“Remington 51: Still One of the Best”, by D.R. Lulling and E.R. Gerbsch, American Rifleman, December 1976.
“The Remington Model 51,” by Donald M. Simmons, Jr., in Gun Digest, 33rd Edition, 1979.
“Remington Model 51 Pistol” in Dope Bag, by Daniel K. Stern, American Rifleman, September 1965.
Textbook of Automatic Pistols, by R.K. Wilson and Ian V. Hogg.  Arms & Armour Press, London:  1975.
Troubleshooting Your Handgun, by J.B. Wood.  Follett Publishing Co., Chicago:  1978.
U.S. Military Automatic Pistols: 1894-1920, by E. S. Meadows.  Richard Ellis Pubs., Moline, IL: 1993.
U. S. Patent 1,348,733
Detailed Photographs of Field Stripping the Remington 51

Remington 51 Prototypes
Remington 51 Prototpyes in the J.B. Cargile Collection
Highlights from the J.B. Cargile Collection of Remington 51s

Copyright 2007 by Ed Buffaloe.  All rights reserved.








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