Hi there,
My copy of AP1086 Book 12 Pt 2 (dated 14 June 1965) has 29A/9419314 as : Precision BSW bolt ‘R’ Steel, Zinc Coated Hex Head 3/4 BSW x 3″ long to BS1083
Additional info is as follows:
Dimensions and general features to BS1083
Thread form and class of fit to BS84 (med)
Material steel code ‘R’ to BS1083 table 9
Finish- Zinc coated to DTD903C
Hope that helps
Regards
Dave