We're installing prefinished red oak with a pneumatic flooring nailer and L cleats. Instead of driving the nails down to the bottom of the groove, the nails are left sticking out by 3/8" or so. We installed the exact same floor in a different house a few years ago with the same tools and had no problems! I swear we've tried everything we can think of to crack the code but are stumped, so here we are!

In a nutshell we've done the following with no luck:

- Tried some extra flooring from the other job on a different subfloor
- Replaced compressor
- Replaced L cleat flooring nail gun

We're stumped! Anybody have ideas for what we can try?

Thanks!

Could there be something under the underlayment/subfloor thats stopping the fasteners from penetrating? Shorter cleats? Higher pressure? Sounds weird.