Printable one rep max chart (1RM Table) for max lifts between 300 and 400.
Note: The further away you get form a single the less reliable the table becomes. For some, the weight you max out with at 20 reps won’t accurately predict your 1RM.
If you have good strength endurance and are use to high reps, it will over shoot your 1RM.
If you’re not used to pumping out a lot of reps, it will undershoot your projected 1RM.
But in the 8 – 12 rep range you’ll be pretty close.