Redding Neck Sizing Bushings- sizes not as stamped.

[Ruger_shooter]

I have two of these bushings, .244 and .245. When I measure their inside diameters I find that they in fact measure .239 and .240 respectively. I expected them to be as exactly as stamped. Are they deliberately made like this to account for the brass springing back when taken out of the neck sizer??

[Treebone]

Ruger Shooter,
If you measured them with vernier/digital calipres you will have got a false reading, the small flats on the edges of ID blades of the caliper will cause them not to measure on the true internal diametre of the bush, thus accounting for the few thousandths difference from the stated bore ID.

TB.

[Ruger_shooter]

Ruger Shooter,
If you measured them with vernier/digital calipres you will have got a false reading, the small flats on the edges of ID blades of the caliper will cause them not to measure on the true internal diametre of the bush, thus accounting for the few thousandths difference from the stated bore ID.

TB.

Thank you for that. Would never have realised that this was the case.

[Treebone]

Thank you for that. Would never have realised that this was the case.

The only true way to measure them is with small hole gauges or Go/No-go plug gauges.

TB.

[MikB]

Ruger Shooter,
If you measured them with vernier/digital calipres you will have got a false reading, the small flats on the edges of ID blades of the caliper will cause them not to measure on the true internal diametre of the bush, thus accounting for the few thousandths difference from the stated bore ID.

TB.

A few tenths, or a thou at the absolute outside, I'd think. I reckon your original springback theory would cover most of the difference.