Great pics and great buck, thanks for sharing. Generally speaking, the main frame of a buck is usually established by the end of June, and then the tine growth takes over in July, many times with exceptional growth (1"/day as LBLman stated) if conditions are right (rainfall, habitat, etc). By the end of July, most buck's antlers are fully formed or very close to it, then the blood flow ceases and the hardening process begins.
One other thing to note is the "bulbous" looking round ends of the tines on this buck, an indicator that they are still growing to some extent. My experience has been the G1s & 2s usually finish growing first, whereas the main beam length and last few up tines are the last two finish up.