My framing nailer is a Hitachi NR83A. Think that is comparable to yours. (Don't remember what your's is.)
For sub-floors I use something comparable to Senco M002041 - Ring Shank Full Rounded Head Nails, 8d, 2 3/8 x .113 (80mm x 2.9mm) Bright Basic... and I put down Liquid Nails Construction Adhesive on the jousts.
That gun nail will fit:
- Senco SN60, SN65, SN65C, FramePro 600/700/750 FRH
- Bostitch N90RHN
- DeWalt D51845
- Hitachi NR83A
- Paslode 5324SRH
- Porter Cable FR350
and knock-off's thereof.
I don't use screws. Screws are slower and if you did use screws, you would have to ensure that all the heads were countersunk below the surface. Other reasons- Screws are more brittle than nails. If there is an application where I have to use screws in a floor (such as in decking), then I also use a type that lock-in so they don't back out from years of vibration.