This is the general guide to WWII gunsights that I go by:
USAAF K-14/RAF GGS Series
P-51D
P-47D
Late model Spitfires (Mk IX on?)
Late war US Navy fighters (F4U-4?)
The US K-14 (and the virtually identical US Navy Mark 18) was a license-built variation of the British-developed gyro-stabilized lead-computing sight. The sights were largely similar, with some differences in knobs, settings, etc., and used a gyro system to permit the reticle to compensate for relative motion in the firing and target aircraft. The reticles were the same in the US and RAF versions.
US Navy Mark VIII (also Mark 8)
All US Navy and Marine Corps fighters and dive bombers:
F4F
F6F
F4U
SBD Dauntless
As Mark 8, some USAAF fighters (P-47D)
USAAF N-3
P-51B/P-51C
P-47C and early P-47D
P-38F-1 through P-38J-5
P-40
P-39
P-61
B-25
B-26
This sight reticle is also identical to the N-2 sight, which was installed on many early P-40s and the P-35. It is suitable for use in any US-built fighter, including those supplied to the USSR and Britain through Lend-Lease. NOTE: This sight consists of a simple circle with a center dot. It differs from my "RAFMark2" sight only in size (my Mark2 is slightly smaller)
USAAF N-9
P-51D
P-51K
P-63
A/B-26
B-25
The N-9 was the standard USAAF fighter sight by around 1943, until it was replaced by the K-14 gyro sights. It is suitable for use in any US-built fighter, including those supplied to the USSR and Britain through Lend-Lease.
RAF GM2 Mark II
(Also known as
GM 2 Mark IIs, Mark II* and Mark III)
Spitfire Mk. Ia through Vc
Hurricane Mk. I, IIc
Brewster Buffalo
Note: Some sources report that US pilots,
on arriving in England in 1942-43, often replaced their US gunsights with British models, so you would not be out of line using this one in the P-38F, P-51B, or the P-47C.
RAF
Type I, Mark II
Late war British fighters:
Tempest
Typhoon
Spitfire Mk V, Mk IX
Mosquito
Beaufighter
Luftwaffe Revi 3D
Bf109D
Bf109E
This is the sight fitted to early-war Messerschmidt fighters, and is appropriate for the Battle of Britain Bf109E.
Luftwaffe Revi 16B
Bf109G-10
FW190A-8
Me 262
Luftwaffe Revi C12-D
Bf109G-10
Bf109G-6
Bf109G-2
Bf109F-4
Soviet Model PBP-1
IL-2
Pe-2
Tu-2
Yak-1, Yak-3, Yak-7, Yak-9U
LaGG-3, La-5, La-7,
MiG-3
This was the standard Russian reflector sight from 1941 onwards.
Japanese Type 98
A6M Zero series
N1K2-Ja
Japanese Type 3
Ki-100 Siki-sen
Ki-84 Hayate
Ki-61 Hien
Post-and-Ring Sight
This is a "generic" sight appropriate for early war fighters of all nationalities. Post-and-Ring sights were retained on later fighters as "backup" to be used in the event of failure of the reflector unit, and many reflector models, like the US N-9, the German Revi sights, and the Japanese sights above, had integrated "rings" for this purpose.
