1) We have checked the stock parts and found ok. See attached pictures.
2) Both parts of 424z3413-1 and 424z3414-1 checked with thread plug gauge and thread ring gauge respectively and again these checked with each other.
3) Gauges used: 0.500-20 UNJF 3A, standard thread plug gauge and 0.500-20UNJF 3B standard thread ring gauge.
4)The thread on the picture seems damaged. So I am no doubt but there is a possibility of thread jam due to wrong entry. So please check at your end once again.
