Every once in a while during hard acceleration I am unable to shift into second and if I try to force it I grind gears, at first I thought I was just failing to press the clutch in far enough, but last time I made sure the clutch was as far down as I could get it.

I'm puzzled because it happens at random and I've never had this issue while under normal driving conditions.

 

2nd gear synchro is worn. You can switch to a high-quality synthetic gear lube to help a little (NEO, Redline, etc...), but the only real fix is replacing the synchro or the transmission.

 

^ This.

Also, just to be sure, make sure your hydraulics are working correctly with the clutch system.