Since a number of doubtful "factory MP5" guns seem to be coming onto the market here is my attempt at identifying the various original German made MP5 models from their serial numbers and markings based on what I have seen in real life and photos.
Adopting suggestions from @Shoegum I have added some photos of typical receiver top and proof markings as well as photos contrasting early and late shelf semi auto receivers with a full auto push pin receiver.
At the very end are links to (1) an excellent post providing photos and details of various sears and trigger pack conversions and (2) the outstanding hkmp5collector website which contains photographs and information that I have not seen elsewhere.
I welcome any suggestions, additions and corrections. I will credit additional information as it comes in.
The date periods are approximate.
From 1964 to the mid 1970's
Apart from prototypes, the serial number was 4 or 5 digits with no letter prefix. The date code was numerical (for example, 12/72 indicated manufacture in December 1972).
This appears also to have been true for MP5 weapons made by HK in Germany, shipped to the UK and then assembled at the Royal Small Arms Factory at Enfield, England, These have EN instead of HK on the receiver top but may have German or English proof marks. The serial numbers are 5 digits starting with 0. Some with broad arrow marks on the barrel or the trunnion housing went into service with the British military where they were issued to the SAS in particular. Others were allegedly used to evade weapon export laws (see The Sleazy State: Royal Ordnance 'exported weapons to East Germany':).
Late 1970's
The numerical month/year date code was replaced by a 2 letter date code indicating the last two digits of the year of manufacture.
A = 0
B = 1
C = 2
D = 3
E = 4
F = 5
G = 6
H = 7
I = 8
J = 9 (on parts not subject to proofing, such as magazines)
K = 9 (on proofed parts, such as receivers, since J on a proofed part meant it had had to be repaired or modified to pass)
At about the same time letter serial number prefixes began to emerge. About 4,000 MP5s were supplied for the Yugoslavian militia and police bearing EN markings, the Yugoslavian national emblem, YU in front of a 5 digit serial number starting with 0 and a date code of HH (1977) or HI (1978). The S-E-F style trigger group housing was marked U-J-R (Ukočeno (Safe), Jedinačno (Single shot), Rafalno (Full automatic)).
1980's and 1990's
By the 1980's the serial numbering of standard German HK MP5 production had become:
C + 6 digits (often starting with 317 (thanks @Raufus) or 319) for the standard MP5. The highest I have actually handled was C335396. 500 weapons - C354221 to C354720 - were supplied to the Swiss Army (source: hkmp5collector website)
C + 5 digits (usually starting with 6) for the MP5-N (although some Enfield standard MP5s also had C + 5 digit serial numbers - see the hkmp5collector website)
S + 5 digits (usually starting with 94, 95, 96 (thanks @Raufus) or 97) for the MP5SD.
4 or low 5 digits with no letter prefix for the MP5K models (thanks @Raufus)
Although the year of the change appears to have varied between different models, during the early 1980's the "skinny" HK logo receiver markings were brought into line with HK's longstanding logo with the left upright of the H being taller than the rest (thank you @tnbigdawg).
MP5A2 and MP5A3 weapons that HK supplied to Norway's police and armed forces were marked with the Norwegian government crest, the later form of the "skinny" HK logo and N followed by 5 digit serial numbers.
Not later than 1984 the Kal. 9mm x 19 marking had been relocated from the receiver top to the left mag well (see @Raufus 's stunning MP5K at https://www.hkpro.com/threads/facto...ds/factory-mp5-transferable-01-start.586473/page-3?post_id=4282846#post-4282846 Post #52).
By 1988 it had become Cal. 9mm x 19.
Thereafter
In addition to the usual model description, the two letter date code and proof marks on top of the receiver, HK began to include a further numerical model designator being the first 2 or 3 digits separated by a dash from the final 6 digits of the serial number:
21- SP89 *
43- HK94 *
49- HK SC5 SD
62- MP5, MP5N, MP5SF #
63- MP5SD
64- MP5K, MP5KN, MP5KPDW
68- MP5/10
69- MP5/40
215- SP5K
271- SP5
272- SP5L
273- SP5PDW, SP5K-PDW
* Earlier guns had a simple 4 or 5 digit serial number without a letter prefix.
# There was an overlap since C + 6 digit serial numbers appear on MP5s with date codes as late as 1992 but serial numbers beginning 62- appear on MP5s as far back as 1988 (source: hkmp5collector website).
HK's later supplies to the Swiss Army have either 62-3xxxxx or A xxxxx serial numbers and those to the Royal Dutch gendarmerie (KMar - Koninklijke Marechausee) have S prefixes to 62-37xxxx serial numbers (source: hkmp5collector website).
There have been internet adverts and auctions showing photographs of weapons that at first glance look like true HK MP5 series guns but have serial numbers starting with 43-, 271- or 273- and so would appear to be HK94, SP5 or SP5PDW conversions. Others have a two letter date code and a 4 or 5 digit serial number without a single letter prefix. With a 4.5" barrel such a gun could be either a true MP5K from the 80's or 90's or the conversion of an early SP89 or HK94. So it is important to see the shelf area as well as the markings on the receiver top. It is usually explicitly stated if the weapon in question was originally a semi auto model that has been re-marked but sometimes that is left to the prospective buyer to discover. Caveat Emptor.
HK MP5 markings in the 1960's and 1970's
![Image]()
The paint was most likely added by an owner rather than at the factory. Note the even height of the letters of the HK logo.
This combination of serial number and date does not mean that by the end of 1972 HK had produced in excess of 82,000 MP5s. During this period the initial 2 digits of the serial numbers of HK marked MP5s seem to have been chosen in no particular order when allocating a serial number range to a specific contract or production run. For example, this later 1976 packing list relates to MP5A3s with much lower serial numbers:-
![Image]()
EN MP5 markings in the 1970's
![Image]()
EN MP5 markings in the 1980's with letter date code and German proof marks
![Image]()
1985 EN MP5 with English proof marks
![Image]()
(Photo credit: hkmp5collector website)
On the right is the proof mark of the Gunmakers' Company of London. Other English proof marks are explained at Testing Firearms: Proof Test
Yugoslavian MP5 contract markings
![Image]()
![Image]()
(Photo credit: DWSUK)
Norwegian MP5 contract markings
![Image]()
HK MP5, MP5SD and MP5K markings in the 1980's and 1990's showing subtle changes in the "skinny" HK logo style during the early 1980's:-
![Image]()
![Image]()
![Image]()
![Image]()
![Image]()
![Image]()
![Image]()
Photo credit: @Raufus (many thanks)
HK markings on a 1983 semi auto HK94
![Image]()
Later 20th and 21st Century HK markings showing variations in the HK logos and in the stamping or engraving
![Image]()
![Image]()
![Image]()
![Image]()
Proof marks
An example of an English proof mark sometimes found on Enfield MP5s:
![Image]()
(Photo credit: hkmp5collector website)
From the 1980's until about 2015 the receiver top of semi auto and full auto MP5 variations that left HK Germany as finished weapons will have a German Nitro proof, a 2 letter date code and the antler of the Ulm proof house:
![Image]()
From about 2015 onwards HK guns will have the international CIP Nitro proof in front of the date code and Ulm proof house mark:
![Image]()
The semi auto shelf
The shelf area of this early semi auto weapon left the factory with only a button mag release:-
![Image]()
The shelf area of this later semi auto weapon has both button and flapper mag releases:-
![Image]()
Contrast these with the equivalent area of an original MP5:-
![Image]()
(Photo credit: ZIB Militaria)
It is essential to see this area with the trigger housing removed since some weapons that left HK as semi autos are now attached, for example, to registered full auto conversion trigger packs and the model designation on the receiver top has been professionally re-marked. Trigger housings are often "clipped & pinned" to hid the unsightly (IMHO) semi auto shelf. The inside of the wings of the housing are modified and stub ends cut from a push pin are fixed to the exterior of each wing to reproduce the appearance of a factory full auto gun:-
![Image]()
(Photo credit: HKParts.net)
Conversion trigger packs and sears
Descriptions and photos of various conversion trigger packs and sears can be found at https://www.hkpro.com/threads/info-...f-different-manufacturers-registered-hk-trigger-packs-sears-an-housings.372810/
MP5 Website
Adopting suggestions from @Shoegum I have added some photos of typical receiver top and proof markings as well as photos contrasting early and late shelf semi auto receivers with a full auto push pin receiver.
At the very end are links to (1) an excellent post providing photos and details of various sears and trigger pack conversions and (2) the outstanding hkmp5collector website which contains photographs and information that I have not seen elsewhere.
I welcome any suggestions, additions and corrections. I will credit additional information as it comes in.
The date periods are approximate.
From 1964 to the mid 1970's
Apart from prototypes, the serial number was 4 or 5 digits with no letter prefix. The date code was numerical (for example, 12/72 indicated manufacture in December 1972).
This appears also to have been true for MP5 weapons made by HK in Germany, shipped to the UK and then assembled at the Royal Small Arms Factory at Enfield, England, These have EN instead of HK on the receiver top but may have German or English proof marks. The serial numbers are 5 digits starting with 0. Some with broad arrow marks on the barrel or the trunnion housing went into service with the British military where they were issued to the SAS in particular. Others were allegedly used to evade weapon export laws (see The Sleazy State: Royal Ordnance 'exported weapons to East Germany':).
Late 1970's
The numerical month/year date code was replaced by a 2 letter date code indicating the last two digits of the year of manufacture.
A = 0
B = 1
C = 2
D = 3
E = 4
F = 5
G = 6
H = 7
I = 8
J = 9 (on parts not subject to proofing, such as magazines)
K = 9 (on proofed parts, such as receivers, since J on a proofed part meant it had had to be repaired or modified to pass)
At about the same time letter serial number prefixes began to emerge. About 4,000 MP5s were supplied for the Yugoslavian militia and police bearing EN markings, the Yugoslavian national emblem, YU in front of a 5 digit serial number starting with 0 and a date code of HH (1977) or HI (1978). The S-E-F style trigger group housing was marked U-J-R (Ukočeno (Safe), Jedinačno (Single shot), Rafalno (Full automatic)).
1980's and 1990's
By the 1980's the serial numbering of standard German HK MP5 production had become:
C + 6 digits (often starting with 317 (thanks @Raufus) or 319) for the standard MP5. The highest I have actually handled was C335396. 500 weapons - C354221 to C354720 - were supplied to the Swiss Army (source: hkmp5collector website)
C + 5 digits (usually starting with 6) for the MP5-N (although some Enfield standard MP5s also had C + 5 digit serial numbers - see the hkmp5collector website)
S + 5 digits (usually starting with 94, 95, 96 (thanks @Raufus) or 97) for the MP5SD.
4 or low 5 digits with no letter prefix for the MP5K models (thanks @Raufus)
Although the year of the change appears to have varied between different models, during the early 1980's the "skinny" HK logo receiver markings were brought into line with HK's longstanding logo with the left upright of the H being taller than the rest (thank you @tnbigdawg).
MP5A2 and MP5A3 weapons that HK supplied to Norway's police and armed forces were marked with the Norwegian government crest, the later form of the "skinny" HK logo and N followed by 5 digit serial numbers.
Not later than 1984 the Kal. 9mm x 19 marking had been relocated from the receiver top to the left mag well (see @Raufus 's stunning MP5K at https://www.hkpro.com/threads/facto...ds/factory-mp5-transferable-01-start.586473/page-3?post_id=4282846#post-4282846 Post #52).
By 1988 it had become Cal. 9mm x 19.
Thereafter
In addition to the usual model description, the two letter date code and proof marks on top of the receiver, HK began to include a further numerical model designator being the first 2 or 3 digits separated by a dash from the final 6 digits of the serial number:
21- SP89 *
43- HK94 *
49- HK SC5 SD
62- MP5, MP5N, MP5SF #
63- MP5SD
64- MP5K, MP5KN, MP5KPDW
68- MP5/10
69- MP5/40
215- SP5K
271- SP5
272- SP5L
273- SP5PDW, SP5K-PDW
* Earlier guns had a simple 4 or 5 digit serial number without a letter prefix.
# There was an overlap since C + 6 digit serial numbers appear on MP5s with date codes as late as 1992 but serial numbers beginning 62- appear on MP5s as far back as 1988 (source: hkmp5collector website).
HK's later supplies to the Swiss Army have either 62-3xxxxx or A xxxxx serial numbers and those to the Royal Dutch gendarmerie (KMar - Koninklijke Marechausee) have S prefixes to 62-37xxxx serial numbers (source: hkmp5collector website).
There have been internet adverts and auctions showing photographs of weapons that at first glance look like true HK MP5 series guns but have serial numbers starting with 43-, 271- or 273- and so would appear to be HK94, SP5 or SP5PDW conversions. Others have a two letter date code and a 4 or 5 digit serial number without a single letter prefix. With a 4.5" barrel such a gun could be either a true MP5K from the 80's or 90's or the conversion of an early SP89 or HK94. So it is important to see the shelf area as well as the markings on the receiver top. It is usually explicitly stated if the weapon in question was originally a semi auto model that has been re-marked but sometimes that is left to the prospective buyer to discover. Caveat Emptor.
HK MP5 markings in the 1960's and 1970's
The paint was most likely added by an owner rather than at the factory. Note the even height of the letters of the HK logo.
This combination of serial number and date does not mean that by the end of 1972 HK had produced in excess of 82,000 MP5s. During this period the initial 2 digits of the serial numbers of HK marked MP5s seem to have been chosen in no particular order when allocating a serial number range to a specific contract or production run. For example, this later 1976 packing list relates to MP5A3s with much lower serial numbers:-
EN MP5 markings in the 1970's
EN MP5 markings in the 1980's with letter date code and German proof marks
1985 EN MP5 with English proof marks
(Photo credit: hkmp5collector website)
On the right is the proof mark of the Gunmakers' Company of London. Other English proof marks are explained at Testing Firearms: Proof Test
Yugoslavian MP5 contract markings
(Photo credit: DWSUK)
Norwegian MP5 contract markings
HK MP5, MP5SD and MP5K markings in the 1980's and 1990's showing subtle changes in the "skinny" HK logo style during the early 1980's:-
Photo credit: @Raufus (many thanks)
HK markings on a 1983 semi auto HK94
Later 20th and 21st Century HK markings showing variations in the HK logos and in the stamping or engraving
Proof marks
An example of an English proof mark sometimes found on Enfield MP5s:
(Photo credit: hkmp5collector website)
From the 1980's until about 2015 the receiver top of semi auto and full auto MP5 variations that left HK Germany as finished weapons will have a German Nitro proof, a 2 letter date code and the antler of the Ulm proof house:
From about 2015 onwards HK guns will have the international CIP Nitro proof in front of the date code and Ulm proof house mark:
The semi auto shelf
The shelf area of this early semi auto weapon left the factory with only a button mag release:-
The shelf area of this later semi auto weapon has both button and flapper mag releases:-
Contrast these with the equivalent area of an original MP5:-
(Photo credit: ZIB Militaria)
It is essential to see this area with the trigger housing removed since some weapons that left HK as semi autos are now attached, for example, to registered full auto conversion trigger packs and the model designation on the receiver top has been professionally re-marked. Trigger housings are often "clipped & pinned" to hid the unsightly (IMHO) semi auto shelf. The inside of the wings of the housing are modified and stub ends cut from a push pin are fixed to the exterior of each wing to reproduce the appearance of a factory full auto gun:-
(Photo credit: HKParts.net)
Conversion trigger packs and sears
Descriptions and photos of various conversion trigger packs and sears can be found at https://www.hkpro.com/threads/info-...f-different-manufacturers-registered-hk-trigger-packs-sears-an-housings.372810/
MP5 Website
