I have used the monolithic 'copper' hollow points for MANY years in MANY different calibers and bullet weights and I have had very good results. Early on they were very temperamental about which gun would shoot them accurately but all of them I have used recently, both hand loaded and factory, have been working well in most guns I have used them in.
As for the 55 gr 223 bullets I personally have not used them but a friend of mine has terminated several hogs with them and likes them A LOT. I have not been able to do a 'post' on any of his kills but if they perform as well as the ones I have used in larger calibers I would think they would be acceptable for up to medium size hogs.
An armed society is not always a polite society, but it is a free and safe society!
Self Defense is an absolute and natural right!
Keep your head down and your powder dry!