Far, far too broad a subject really, there were dozens if not hundreds of different small arms rounds in use in WWII, if you want to compare specific ones why not open up a separate thread like the "... vs ..." threads that appear. If you'd like to see your thread generate some replies, try putting something in of your own opinion, a good example would be a kind of "I think -insert appropriate bit of kit here- was the best because...". Even if you know next to nothing about the subject matter, you'll almost certainly get a reply or two, either people agreeing with you or disagreeing. If you really don't know anything at all, or wouldn't feel comfortable sticking your neck on the block in such a way, ask a question. Here from your post it isn't clear what if anything you're expecting to hear. Asking, for example "What was the best/worst Rifle round of WWII?" Would be a better option. Unfortunately basically posting "-Insert type of equipment- discuss" isn't likely to get many responses at all, except for ones like this telling you that the subject matter is too broad. Not intending to have a go or teach you to suck eggs, just constructive criticism.
In case of any cultural confusion caused by Simon's egg remark... The full English saying is 'to teach your Grandma to suck eggs' - which means to tell somebody something they already know, or more usually to tell somebody how to do something that they know how to do. An example would be to instruct Merlin how to make good puns... :smok: