Large error in Zeroing No 1 Mk III* at 25 yards - your thoughts, please?

[22SqnRAE]

G’Day Enfield Experts,

I have a zeroing issue and I’m stumped to understand how/what/why. Maybe your collective experience and knowledge may help? I have read the previous posts and articles on how to zero, how to adjust foresight blades and the like. This situation is beyond not following basic instruction.

I have a No 1 Mk III*, FTR Lithgow in 1956. Zeroing at 25 yards, the following 3 shot groups were observed:

Sights @200yd MPI +3.15” above POA
Sights @300yd MPI +4.13” above POA
Sights @400yd MPI +4.13” above POA

Foresight is 0.015” blade. Ammunition is Privi Partizan 174gr FMJ, MV 2460fps (published). While not Service Mk VII ball, I won’t agree that commercial or handloaded ammo will be this far out. I have recorded similar errors at 100m with hand loads known to be spot on in other No 1 Mk III* rifles I have. I appreciate that hand loads can be a little different in performance to commercial and service ball, but not this much difference.

Zero for 200yd, according to REME Armourer training pam, at 25 yds should have MPI 0.75” above POA, or at 100yds MPI 3” above POA.

The observed groups are touching, so my sight picture is OK. Sights are not.
No chance of adjusting POI by changing foresight blade, as highest blade is 0.03” and I’d need 0.69” or thereabouts!

What are your thoughts on correcting this conundrum? (Rear sight leaf is not loose, nor is any other component, headspace is between 0.064” and 0.072”)

I’d appreciate your views on how to approach this situation. Something is well out of whack…

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