Need advice: Armband vs HRM

crazy4fids

NEED ADVICE
This was my workout today:
10 minute warmup
leg extensions 10/30 lbs, 10/50, 5@6/70
leg curls 10/50, 10/70, 2@6/90
leg press 10/30, 10/50, 5@6/70
glutes 10/50, 10/70, 6/90, each leg
elliptical 15 minutes
stretch for 15
Now my BodyMedia Fit armband says that while I was at the gym, I burned 315 calories in a little over an hour.
My new Garmin FR70 HRM says I burned 701 calories in the same amount of time.
I wouldn't complain if the numbers were within 100 points of each other, but a 386 point difference?
What's up with that?

rockerbabyy

HRMs arent really made for weightlifting so id ignore that completely.
id go with the BMF even though they can be off by like 10% as well, but at least it measures more than just heart rate.