http://www.303british.comNot knowing exactly what it is you want to know, I'll add my unsolicited $0.02 worth.
Use the right bullet diameter...which is .311".
I have not found a military No.4 barrel that would group a boat-tail bullet at 100 yards. The boat-tail pills I have used had "gone to sleep" by 200 yards.
If you are using a No.4 rifle, more often than not, it will take a number two or number three bolt head. Use the longest (biggest number) bolt head that will allow the bolt to close on the brass you are using.
Avoid full length case resizing like the plague.
Hope this helps.