Belgian Browning Auto-5 Serial Code Decoder
Use this Browning serial number lookup reference to narrow the likely manufacture period and identify the correct Auto-5 model or series. Enter or compare the available markings, then verify the result against the supporting serial-range notes and collector references below.
By Greg Cook · Updated August 29, 2026 · Collector Reference
How to Look Up a Browning Auto-5 Serial Number
This decoder covers Browning Auto-5 shotguns made by FN in Belgium and explains the later Japanese Miroku system for comparison. It does not date every Browning rifle, pistol, or shotgun model. Getting an Auto-5 date right requires identifying the serial-number era and the model letter—if present—before choosing a production table.
- Copy the complete receiver serial: include every letter, digit, and prefix in the order stamped.
- Confirm the maker: check for “Made in Belgium,” Liège proofs, or “Made in Japan” before selecting the FN or Miroku system.
- Decode the model letter: use the table below to separate Standard Weight, Light Twelve, Magnum, Sweet Sixteen, Standard 16, and Twenty variants.
- Compare the correct era: match the full format—not merely the numeric portion—then verify gauge, weight, barrel, and proof markings.
Belgian Auto-5 production ran from 1902 through 1976 and passed through several serial formats as production expanded, WWII interrupted output, and FN introduced model codes. Published ranges can estimate manufacture periods, but factory documentation remains the better source when an exact date is important.
Model Letter Code Quick Reference
If your serial number contains a letter, find it here first.
| Letter | Model | Gauge | Weight | Production Years | Notes |
|---|---|---|---|---|---|
| H | Standard Weight (early) | 12 ga. | Standard | 1954–1956 | Used briefly; replaced by M in 1957 |
| M | Standard Weight | 12 ga. | Standard | 1957–1976 | Primary 12-ga. standard code |
| G | Light Twelve | 12 ga. | Light | 1956–1976 | Preceded by L (1952–1955) |
| L | Light Twelve (early) | 12 ga. | Light | 1952–1955 | Replaced by G in 1956 |
| V | Magnum | 12 ga. | Standard | 1958–1976 | 3-inch chamber; V = Magnum |
| S | Sweet Sixteen | 16 ga. | Light | 1953–1976 | Preceded by separate 16-ga. sequence |
| R | Standard Weight 16 | 16 ga. | Standard | 1953–1966 | Discontinued 1966; do not confuse with S |
| X | 20 Gauge | 20 ga. | Standard | 1958–1976 | 20-gauge introduced 1958 |
| (none) | Standard Weight 12 | 12 ga. | Standard | 1902–1953 | Pre-letter era; all digits |
| ABC | Remington wartime | All | — | 1940–1946 | A = 16ga, B = 12ga, C = 20ga; US-made |
Decode Your Serial Number
Enter the serial number exactly as it appears on your receiver. Include any prefix letters and digits — no spaces.
Need the full A5 tool and charts? Open the Browning A5 serial number lookup.
Browning Reading and Gun Care
- John Moses Browning: The Life and Legacy of the American Gunsmith Who Modernized Automatic and Semi-Automatic Firearms
- TempPro TP50 hygrometer Same unit as the ThermoPro TP50 on the humidity guide. Cheap, and it tells you if the safe is wet.
- Birchwood Casey Synthetic Gun Oil 10-Ounce Aerosol Long-Lasting Gun Lubricant The natural solvency of Synthetic Gun Oil cleans as it oils while its low evaporation rate assures protection against rust.
The Six Belgian Serial Number Eras
FN's serial number system evolved over 74 years of production. Understanding which era your gun belongs to is the first step to dating it accurately.
Pre-War Sequential (1902–1939)
All-digit serial numbers · 12-gauge only · No letter codes
From the model's introduction through the outbreak of WWII, FN used a single sequential number series for all 12-gauge Auto-5s. No model letter, no year code — just a number. Pre-war guns begin at serial number 1 and run to approximately 228,000. Precise year-by-year breakdowns are not available from FN's records; the table below reflects Browning Arms Company data.
| Year | Serial Range | Notes |
|---|---|---|
| 1902–1903 | 1 – ~5,000 | First U.S. shipment; marked "BROWNING AUTOMATIC ARMS CO. OGDEN UTAH" |
| 1904–1910 | ~5,001 – ~45,000 | — |
| 1911–1914 | ~45,001 – ~100,000 | — |
| 1915–1918 | No Belgian production — German occupation of Belgium; FN factory seized | |
| 1919–1930 | ~100,001 – ~160,000 | Production resumes; address changes to Browning Arms Co., St. Louis, MO |
| 1931–1939 | ~160,001 – 228,000 | Three-shot "Auto-3" variant available; J.M. Browning bust added to receiver legend |
WWII Remington Production (1940–1946)
A/B/C prefix · US-made · Not Belgian FN
With Belgium under German occupation beginning in 1940, Browning licensed Auto-5 production to Remington Arms in the United States. Remington-made guns are identified by the letter prefix: A for 16-gauge, B for 12-gauge, and C for 20-gauge. These are American guns — mechanically similar to the Belgian original but not FN-manufactured.
| Code | Gauge | Notes |
|---|---|---|
| A | 16 gauge | US-made by Remington; marked on receiver |
| B | 12 gauge | US-made by Remington |
| C | 20 gauge | US-made by Remington |
Post-War Belgian Sequential (1946–1953)
All-digit continuation · 12-gauge standard weight · No letters
FN resumed Belgian production in 1946, picking up the sequential series where it had left off. Serial numbers in this era are all-digit, running from 229,000 to approximately 438,000 by the end of 1953. No model letter is present; all guns in this range are 12-gauge standard weight unless the receiver is marked otherwise.
| Year | Serial Range |
|---|---|
| 1946 | 229,001 – 237,000 |
| 1947 | 237,001 – 249,000 |
| 1948 | 249,001 – 270,000 |
| 1949 | 270,001 – 285,000 |
| 1950 | 285,001 – 315,000 |
| 1951 | 315,001 – 346,000 |
| 1952 | 346,001 – 387,000 |
| 1953 | 387,001 – 438,000 |
Letter Code Introduction (1952–1957)
H / L / M / G / S / R prefixes introduced
As FN expanded the Auto-5 line to new variants, a letter code system was introduced to distinguish them. The letter system evolved quickly between 1952 and 1957 — two codes changed during this short window.
| Year | Code Change |
|---|---|
| 1952 | L prefix introduced for Light Twelve; standard weight 12ga remains all-digit |
| 1953 | S prefix introduced for Sweet Sixteen; R prefix for Standard Weight 16ga |
| 1954 | H prefix introduced for Standard Weight 12ga (replaces all-digit for new production) |
| 1956 | G replaces L for Light Twelve; H continues briefly |
| 1957 | M replaces H for Standard Weight 12ga; G, S, and R continue |
| Prefix | Model | Years | Approx. Range |
|---|---|---|---|
| L | Light Twelve | 1952–1955 | L 1 – L 83,000 |
| H | Standard Weight 12ga | 1954–1956 | H 1 – H 99,000 |
| G | Light Twelve | 1956–1957 | G 1 – G 85,000 |
| M | Standard Weight 12ga | 1957 | M 22,000 – M 85,000 |
| S | Sweet Sixteen | 1953–1957 | S 1 – S ~80,000+ |
| R | Standard Weight 16ga | 1953–1957 | R 1 – R ~40,000 |
Single-Digit Year Code (1958–1967)
Format: [digit][letter][serial] · 20-gauge introduced
In 1958, FN standardized a year-coding system across all Auto-5 variants: a single digit representing the last digit of the year was placed before the model letter. The same year digit was used for all variants that year, making any 1958 gun start with '8' regardless of gauge or weight. The 20-gauge Auto-5 was introduced in 1958 under the X code.
| Year | Digit | Model Codes Active |
|---|---|---|
| 1958 | 8 | 8M (SW12), 8G (LT12), 8S (Sweet16), 8R (SW16), 8V (Mag12), 8X (20ga) |
| 1959 | 9 | 9M, 9G, 9S, 9R, 9V, 9X |
| 1960 | 0 | 0M, 0G, 0S, 0R, 0V, 0X |
| 1961 | 1 | 1M, 1G, 1S, 1R, 1V, 1X |
| 1962 | 2 | 2M, 2G, 2S, 2R, 2V, 2X |
| 1963 | 3 | 3M, 3G, 3S, 3R, 3V, 3X |
| 1964 | 4 | 4M, 4G, 4S, 4R, 4V, 4X |
| 1965 | 5 | 5M, 5G, 5S, 5R, 5V, 5X |
| 1966 | 6 | 6M, 6G, 6S, 6V, 6X (R discontinued — SW 16ga ends 1966) |
| 1967 | 7 | 7M, 7G, 7S, 7V, 7X |
Two-Digit Year Code (1968–1976)
Format: [2-digit year][letter][serial from 1000] · Final Belgian era
To eliminate ambiguity as the 1960s ended, FN switched to two-digit year prefixes in 1968. The format: two-digit year + model letter + sequential serial (beginning at 1000). Example: 69G1000 = 1969 Light Twelve, serial number 1000. Belgian production ended in 1976.
| Year | Prefix | Active Models |
|---|---|---|
| 1968 | 68 | 68M, 68G, 68S, 68V, 68X |
| 1969 | 69 | 69M, 69G, 69S, 69V, 69X |
| 1970 | 70 | 70M, 70G, 70S, 70V, 70X |
| 1971 | 71 | 71M, 71G, 71S, 71V, 71X |
| 1972 | 72 | 72M, 72G, 72S, 72V, 72X |
| 1973 | 73 | 73M, 73G, 73S, 73V, 73X |
| 1974 | 74 | 74M, 74G, 74S, 74V, 74X |
| 1975 | 75 | 75M, 75G, 75S, 75V, 75X |
| 1976 | 76 | 76M, 76G, 76S, 76V, 76X — Final year of Belgian FN production |
Post-1976: Japanese Miroku Serial Numbers
Beginning in 1976, production shifted to Miroku in Japan. The Japanese serial system is completely different from the Belgian FN system and must not be cross-referenced with the charts above.
Miroku Serial Number Format
[Serial Number] + [Date Letter] + [Date Letter] + [Type Code]
Example: 01001RT151
- 01001 = Serial number
- R = Date letter (R = 7)
- T = Date letter (T = 6) → 76 → 1976
- 151 = Magnum 12-gauge
Date Letter Decode
Type Code Reference
| Type Code | Model |
|---|---|
| 151 | Magnum 12 gauge |
| 161 | Magnum 20 gauge |
| 211 | Light 12 gauge |
| 221 | Sweet Sixteen |
| 231 | Light 20 gauge |
How to confirm Miroku production: Look for "Made in Japan" on the barrel. Belgian guns are marked "Made in Belgium" or carry Belgian proof marks (star-in-oval, ELG crown).
Belgian Proof Marks — Confirming FN Origin
Belgian FN guns carry government proof house marks from Liège. These appear on the barrel, receiver, and sometimes the magazine tube. Knowing these marks confirms a gun is genuinely Belgian — important when a serial number alone leaves doubt.
ELG in Oval (Crowned)
Definitive Belgian Liège proof. Appears on virtually all FN production. The crown over ELG signifies nitro proof acceptance.
Star in Oval (PV)
Smokeless powder provisional proof. Common on all post-1898 Belgian guns.
Perron Symbol
Liège city symbol (a pillar with spheres). Appears on guns proved at the Liège proof house.
Inspector's Initials
Small letter stamps, often found on barrel flats. Indicate individual inspector acceptance — helpful for dating within a production window.
Common Dating Mistakes to Avoid
- ✕ Do NOT apply the 12-gauge chart to a 16-gauge gun. The Sweet Sixteen (S prefix) and Standard Weight 16 (R prefix) ran completely independent serial sequences.
- ✕ The H prefix (1954–56) is easily confused with a date digit. If your serial looks like H12345, the H is a model code, not a year indicator.
- ✕ Guns shipped from FN could sit in Browning's warehouse for months or even years before sale. The serial number gives the manufacture year, not the purchase year.
- ✕ A gun with no letter prefix and a number below 228,000 is almost certainly pre-WWII. A number between 229,000 and 438,000 is post-war Belgian (1946–1953).
- ✕ Japanese Miroku guns are well-made and should not be dismissed — but they are not Belgian. The two systems are completely separate.
Frequently Asked Questions
Enter the complete Auto-5 receiver serial exactly as marked, including every letter and year digit. Use the model-letter table to identify gauge and weight, then compare the number with the matching Belgian FN era or later Miroku code system.
Not in every case. Some Belgian Auto-5 eras use approximate ranges, records are incomplete, and shipment or sale dates can differ from manufacture dates. Treat the decoder as an estimate and use factory records when an exact documented date matters.
Check the barrel's “Made in Belgium” or “Made in Japan” marking, Liège proof marks, gauge and chamber marking, receiver model letter, weight configuration, and other barrel and receiver codes.
Check the barrel marking — Belgian guns say "Made in Belgium" and carry Liège proof marks (ELG in crowned oval, star in oval). Japanese guns say "Made in Japan." Additionally, Belgian production ran 1902–1976; any Auto-5 built after 1976 is Japanese Miroku. The serial number format also differs completely.
A pure all-digit serial places your gun in one of three windows: 1–228,000 is pre-WWII Belgian (1902–1939); 229,001–438,000 is post-war Belgian (1946–1953). All-digit guns are 12-gauge standard weight — FN's letter system was introduced specifically to mark new variants.
M = Standard Weight 12-gauge Auto-5. FN introduced the M code in 1957 to replace the earlier H code. If a year digit precedes it (e.g., 6M, 71M), those digits identify the year: 6 = 1966, 71 = 1971.
S = Sweet Sixteen (lightweight 16-gauge); R = Standard Weight 16-gauge (heavier frame, no receiver milling). Both used separate independent serial sequences. The Standard Weight 16 (R) was discontinued in 1966; the Sweet Sixteen (S) continued through 1976. Never cross-reference the two charts.
Yes — with the WWII exception. From 1902 through 1939, and again from 1946 through 1976, all Belgian-market Auto-5s were manufactured by Fabrique Nationale de Herstal in Liège, Belgium. The 1940–1946 guns with A/B/C prefix codes were made by Remington Arms in the United States under wartime license.
V = 12-gauge Magnum, chambered for 3-inch shells. The Magnum variant was introduced in 1958 alongside the year-code system, so all V-prefix guns have a year digit or two-digit year before the V. Example: 4V = 1964 Magnum; 72V = 1972 Magnum.