expansion of hairspring on in-house movement

[dweller]

i have had a 351 with a p.9000 movement for some time now. was looking at it recently then just realised that the hairspring does not expand evenly...one half seems to expand a lot more than the other... not sure if this is normal cos i don't see it on my other watches

any of the bros here care to share their observations on their own in-house pam movements?