I'm not sure what the weight difference is, but it is definitely noticeable. I have at times indeed thought it was a mistake getting a 16" HBAR. The lighter barrels are quick handling, but for quick follow up shots I find the HBAR doesn't have as much flip. My Oly HBAR is a tack driver and as the round count rises the heat doesn't shift the point of impact as much as it would on a lite weight barrel. So would I trade my HBAR in on a lite profile barrel. Hell no! Will I be building a quick handling lite weight rig, hell yes! If the girl you are shopping for is going to keep a reasonable rate of sustained fire, I Would definitely suggest going with a lite weight barrel. Don't get me wrong here, but anyone can appreciate the weight savings, even more so of those that don't have a lot of upper body strength. What kind of shooting does she plan on doing?