Front Sight Blades Lee Enfield No1 No4 SMLE, No5 Carbine
Front Sight Blades for Lee Enfield No1 and N4 SMLE RIfles and No5 Carbines and their derivatives. The front sight blade came in 0.015" increment height variations from -0.045 through to +0.120 (the -0.030 to 0.090 sizes wer approved for rifle factories and armourers - the other sizes are for STEN or sporting origins but fit all anyway).
There are four major derivatives of No4 Rifle Front Sight Blades - changing the rear chamfer and adding the split base - the solid base used on split sight blocks and split sights on solid sight blocks (I recommend split base blades for use in No5 Carbines). Marked for size per the No4 rifle datum. Marked for factory of manufacture:
CA - Canadian Arsenals
F - Fazakerley (Faz)
LB - Longbranch
M - Matlby
N69 - Singer Machine
S - Savage
S in Square - Stevens Mfg (SS)
S.M. - Singer Machine
Longbranch (CA) and Savage examples used a relaxed specification for blade body width and are notable wider than British produced front sight blades.
When adjusting zero for your rifle - add a taller sight blade when Point of Impact is high and a shorter blade when POI is low. For a 303 Mk7 rounds I have observed around 3 inches of elevation / depression change at 100 yards for each size of front sight (0.015”). For 308 (Nato 7.62 x 51) rounds I have observed 2 inches of elevation /depression.
These will fit other Enfield rifles from other factories such as the No1, No2, Ishapore 2A and the Pattern (19)14 (No 3) and Model of 1917 rifles (Also No 3 rifles), but the sight datum is 0.060" higher so add +0.060" to the stamped sizes on these rifle. A +0.015 No1/4 blade is equivalent to a +0.075 P14 / M17 blade.