It depends on a lot of factors, where you start from in terms of strength, what your nutrition is like, if strength is your only goal etc. If it helps I've been training consistently for about as long as I've been a member here, and my max squat was just over 300lbs at the end of march. My diet has improved gradually over that time to what I think is fairly clean, but my goals have been varied, since fat loss was probably my biggest concern initially.
In the end most people could get to a 300Lb squat, 150Lb bench and 350Lb Deadlift... it is merely a matter of how long. If you are training pure in powerlifting then your gains will come a bit faster than not. If you are doing other things as well and training for hypertrophy instead of strength it will take longer etc.
I just started the Bill Starr 5x5 program to get some base strength after losing my gains after a while of not working out. I play basketball and run track. I train for power, strength, speed, and explosivness.
How long was your break from the weights? If it was quite a while, ie over 6 months then i wouldn't recommend going straight into a strength program.
I did a 9-week cycle of a modified Bill Starr 5x5 (madcow intermediate variation) and my squat went from 230 to 260 for 5 reps. The program ramped up to your current max on the 4th week, then over the next 5 weeks, the weight went up consistently by a small percentage until it hit 260. After 9 weeks of training heavy (for me) I saw pretty good gains in strength, and more gains in muscle and even more gains in fat. I over-ate a bit just to make complete use of the training and help recovery. Also after 9 weeks, I definitely needed a solid week off. Now I'm working on cutting back some fat without losing the mass. Its more weight than I want to be carrying around as I'm focusing on all around athleticism, not just pure strength. Even so, used in cycles, its been the most effective program I've used to increase max strength and I plan to use it again over the winter. I don't mind the extra fat during the cold months.
