I bought a heavy HF 04041 21 degree wih plastic collated nails just to
check it out for a small project prior to doing a deck. It is around 10
lbs though.

I found some generic 21 degree nails and they say that they are for
these guns:

Dewalt D51845
Hitachi NR83A and NR90AC2
Porter Cable FR350 and FR350MAG
Senco All Fram Pro 600 FRH and 700FRH series

Hope this helps.

RonT