If it is a M6.4 x .5 I have about 17 left in stock.
The actual number is M6.4-.5 D4 4F TP
Mike this is not the correct size. I have that tap got it form you, its for the smaller Heritance feeds. I just tried the feed in a Jr Gent front section and it did not fit. Looking at the threads on the Heritance feed they are much smaller and finer than the Meisternib or Jr Get feed.
Justin if memory serves we went through this same ordeal a few years ago when several of us were wanting to expand our pen making and the smart guys concluded that the threads inside the Jr Gent section like many other kits have a really oddball pitch, one that will have to be ordered.
It's all a little fuzzy now but one member, might have been Brobbins, actually sent a few kit sections in to have the thread pitches measured but at that time no one was really interested in getting taps to match kit sections since we were all going kitless anyway.
Good luck finding the right tap for your kit sections.