The press is stuck

[TeaTime]

4th week of Starting Strength (practical programing flavor). Squat, deadlift, bench, chin ups all progressing nicely, press is weird. It seems like every time I try it, its much harder/easier from the last time. Started at 55 pounds gone up to 75, last night I am back to 65 (BB weight included).
my gym doesn't have a squat rack only a smith so I am doing the press from the bench rack. Perhaps the un-racking is the culprit?

[Mark Rippetoe]

Too many variables that way. But how are you doing your squats?

[TeaTime]

I do the squat warm up from the bench rack, the work sets on the smith .I know it's a shitty way to do it, but that's the only place with real iron around and i figured smith squat is better then no squat.
Anyway it will change in about 4 months, I'm starting college and they have a real gym, but in the mean time I don't want to rot a home just because of limited resources.

[Mark Rippetoe]

Look, TT, we've talked about this many times. You can't do the program without a way to do the exercises in the program. I'm sorry, but a Smith machine is not a barbell.

[TeaTime]

My press is stuck because I do smith squats?

[Mark Rippetoe]

Your progress has stalled because you aren't doing the program. How are doing presses from the bench rack?

[TeaTime]

I do a sort of a curl to the shoulders, stabilize it to the press position and then press.

How shall I proceed? I don't want to waste the next 4 month, and there is no other gym with iron barbell around.

[Mark Rippetoe]

Buy some equipment like most other people in your situation do.

[JLascek]

Mega hormones from squatting can help the press. Mega.