These seem to be a popular topic at present, so perhaps the following (from my database) in one place may be useful:
A : Various : Sellier & Bellot (Czech) pre-WW2. Significance of the ‘A’ is not known.
Very small “A” : CCI on improved primers - eg on Speer Gold Dot (AFTE.com)
A (Large) : Believed Alcan (on S&W cartridges.
ATS : Atelier de Construction de Tarbes, Tarbes, France also used on ATE cases
Atelier de Construction de Toulouse, Toulouse, France
B : various ? : See Atzl, Scheiring. Small “B” primer on 7x67 Leuven (W115) .
“B” primer is known to represent Bofors (Reuter).
US : Manufactured for Cor-Bon by Federal and the “B” stands for bench rest.
Swedish ? : Small B known on Norma cases in 1981
CCI marks its BR-2 and BR-4 primers with a “B”
C (large) : On CBC Magtech and other CBC cases
CD : French - Chaudun & Deriviere (Cf. “GD”)
C F : US CCI Blazer : CF = “Clean Fire”
C. F. PARIS : Cartoucherie Francaise
C R : On CBC Magtech CR = “Clean Range”
D * * * : French - Devilliers on Mock-Duel cartridges (5-pt stars)
DA. : Dansk Ammunitionsfabrik ?? - see also “Star”
D.A.G. DAG (RWS) Germany
E = US Precision Ammunition = Fire Frangible
G : French : An early product of GEVELOT, use of which is known to have been discontinued by 1875.
GD : French - Gaupillat & Delion (?) See Gaupillat.
GEVELOT * GG * : French : SFM on large rimmed primers c2024
GG (monogram) : SFM
GJ (Raised) : France : GEVELOT Jules c1845-1885 [see FR105]
H * * * : On Austrian shotshell - likely Hirtenberger. Prob cWW1 (6-pt stars)
H F : US Remington : HF = “Heavy-metal Free”
HWM : Belgium - by or for HARALD WOLF MASTERGUNWORKS ??
I (capital I or 1) : for IMPALA by ?
ICI (monogram) : Imperial Chemical Industries on Kynoch hs used xx-yy ?
K (in offset circle) : Likely German on KNIPP cartridge primers (see KNIPP),
“K” primers known by 1984.
K (large letter with serifs) : Likely German : - for KLAUS by ?
L : Likely German : On 11.5x50R Werder with GECADO *" hs. 8x72R,
9.3x72R S&S (B.Stahl) 9.3x72R (Likely Lignose but poss Lindener)
L : Stylised “L” being the LIBRA Registered trademark
L F : US Remington cartridges : L F = “Lead Free” primers
M (in part circle) : Czech : Produced by ZBROJOVKA BRNO c1928-1934.
MG * * * : French : Marcel Gaupillat & Co
MGM ooo : French MGM c1935-1978
m|m : Müller Munition
M&S : Mayer & Sohn : early-mid 1980’s. Produced by ?
N (in shield) : Germany : Produced by RWS from c1928 till approx WW2 on SINOXID (patented corrosion free primers). The ‘N’ stands for the RWS Nurnberg factory. RWS supplied primers to other cartridge manufactures and that is why these can be found on GECADO, M+FA, DWM and other manufacturers cases (although reloads also exist of course).
NP (combined) : Swedish/Nowegian : Produced likely post WW2 till c1990 by
NORMA PROJEKTILFABRIK. Used only by factory indicating Norma loads.
NR (as >NR<) Czechoslovakia - NEROXIN Brand of non-rusting primer made by
Sellier & Bellot. “NR” stand for Nerezavějící (rustproof). Patented 1933.
O The “O” or “0” primer marking used with CBC’s ammunition indicates a
Mil-Spec primer. Found on quite a few US mil experimentals.
P, P (in circle) : On Peters primers prior to 1960
R (in shield) : Germany : Produced by RWS from 1905 till 1925.
R : Norwegian : Produced by Government arsenal RAUFOSS
RN : Norwegian : Produced by Government arsenal RAUFOSS AMMUNISJONSFABRIKKER to be used on reloaded sporting cases to indicate genuine factory loadings. RN = Raufoss/Norma (see RANO)
RWS : Germany : Used by RWS, known of in 1963
RWS N : Germany : Used by RWS
S : Likely German - poss RWS : On 8x68RS experimental likely post 2000
SFM * GG * : French : Produced by SOCIETE FRANCAISE DES MUNITIONS DE CHASSE. On large primers generally for revolver and tool ammunition. Eg FR33
SINOXID : Germany by RWS from c1928
SM : Swedish : (Offset) SVENSKA METALLVERKEN post WW2 till c1965.
S M : German : SM Chemnitzer Sportwaffen und Munitionsfabrik
TESCO : German : Teschner-Collath on large rimmed primers from c1924
T3 monogram : Czech : Produced by POVASKE STOJARNE (PS) c1945-1954. Primer is generally referred to as the “T3” the significance of which indicates the corrosion free properties of the primer. SBP had it’s own NEROXIN type.
U : (Unconfirmed) Germany: Believed produced by H.Utendoerffer-RWS until 1905.
U (in shield) : RWS registered in Germany in 1929.
U (bucket shaped) : On CBC Magtech.
U, U (underlined : USA - On UMC primers prior to 1911 & Remington later…
US, US monogram : Used by United States Cartridge Company (USC Co.) before 1938 on most calibers including European Sporting.
V : Czech : Sellier & Bellot from 1935-cWW2. V believed to represent the Vlasim factory.
VV (double opposed v’s) : Believed CBC.
VIS : Italian : Leon Beaux
VIS NOX : Italian : Leon Beaux (corrosion free)
VP (monogram) : Used on a variety of manufacturers handgun cases (WIN, FC)
which may be related to the VAPEX company.
W, W (in circle) : USA - Winchester Repeating Arms Co
Z (in circle) : Czech : Produced by ZBROJOVKA BRNO c1928-WW2.
ZL : Lienhard and represent ‘Zündhutchen Lienhard’ . ZL is a trade mark.
Acorn : RWS (DNAG - also used on RF
Circle : Evidently RWS indicating Sinoxid primed for handgun ammunition.
See also “O”
Crescent : French : Produced by SOCIETE FRANCAISE DES MUNITIONS DE CHASSE.
Diamond/ 4 sided star - RM-S = the Rheinmetal Logo :
Horseshoe : The Horseshoe was a trademark of Sellier & Bellot, Schönebeck plant (Austrio-Hungary) and was stamped on copper primers typically on ammunition with early “SB” hs. This symbol was used later by Munitionswerke Schönebeck Germany (on primers ?) but interestingly this was not its successor !?
Leaf (Walnut): Originally Badische Munitionfabrik. later Gustav Genschow (GECO).
Leaves with Acorns : Germany : Evidently produced by GUSTAV GENSCHOW (GECO) as this is one of their company symbols. Also found on cartridges with “L” hs believed produced by LIGNOSE (unconfirmed - less likely is LINDENER).
∏ (Pi Symbol) : Actually represents a gate and so could be Svenska Metallverken or Svenska Metallverken
SPADE : Scandinavian ? Found mainly on 12x44R with “MASENG” hs of unknown manufacturer but may be a reload and the primer could have come from any source. Also on or 12x44R with "HAGEN 12 * " hs and also 10.2x57R LV with “HAGEN 10-2” hs. Note that CARTOUCHERIE FRANCAISE used a spade symbol on Rimfire ammunition for export. [Moss] ACE in Leeds, had primer cups embossed with the outline of a Spade (the playing cards suit, not a shovel).
Recently used by ZERO of England.
Star : Germany: Produced by RHEINISCH METALLWAREN u MASCHINENFABRIK, SOMMERDA.
Star : Denmark: Produced by Dansk Ammunitionsfabrik - small off-set 6-point star
Swiss Cross : Swiss : Produced by Government Arsenals EIDGENOSSISCHES MUNITIONSFABRIK ALTDORF and THUN. Used from 1919-1942.
V (truncated V with flat bottom) - CBC
Four dots on DWM primers
Any corrections, updates or additions are welcome !