How far down the tube are you getting a 27.2mm reading?
Could it be that the tube has previously been reamed from 27.0mm to 27.2mm, but only 50mm down?
@Scilly.Suffolk started
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How far down the tube are you getting a 27.2mm reading?
Could it be that the tube has previously been reamed from 27.0mm to 27.2mm, but only 50mm down?