Priming tap

Gents,
I have an Argosy domestic type pump and over the years the brass priming bolt has become rounded and now cannot be removed. I am planning to try an Easiout and it that fails drill and retap the hole.
Rather than use a bolt I have seen straight drain taps, often advertised for Wolseley engines, has anyone tried using one as a way to prime the pump?
Thanks in anticipation

If you mean the bung in the top of the air vessel it is not normally a priming tap but a plug to add/remove air from the vessel to cure water hammer caused by the piston, however, the tap you are talking about would do the job, I'd think the hole would be a little small to pour water in thou....

Thanks I think I may as well stick with a bolt, if it was designed to have a bolt why change it.