czvz,
The "transfer bar" is not an obscure concept. It is a thing that you can easily see. Watch the hammer as you slowly cock it (pull it back). As you do so, you will see a small bar of metal come up and forward between the hammer and firing pin, and come to rest on the back end of the firing pin. This small metal bar is the transfer bar. Furthermore, look at the hammer, and you will notice that it is notched, so that it is impossible for the hammer itself to come in contact with the firing pin. Your gun will not fire without the transfer bar. The transfer bar falls away after you pull the trigger. If you lightly pull and release the trigger before the hammer has had time to fall, the transfer bar may fall out of position prematurely, causing a weak (or failed) firing pin strike.
The transfer bar is an invention of the modern corporate lawyers, and is supposedly put there to make the gun safer (prevent accidental discharges). I'm not sure how it accomplishes this, as my bar seems to come into place even before I pull my trigger. I am told that old-timers despise the transfer bar because of the affect that it has on trigger pull. I've never shot a pre-transfer bar gun, so I can't tell you what the difference is.
Duane