309 lb works out to 2x45 + 1x35 + 1x5 per side plus the bar — call it 305 lb in practice, since gyms rarely stock the odd change. 5 reps sits comfortably inside the 2-to-10 range these formulas were fitted on, so this estimate is about as reliable as the method gets. Your 265 lb set represents about 86% of the estimated max.
How far 309 lb can be trusted
Five reps is the most common way people estimate a max and the rep count these equations were checked against most often. The seven put your max between 298 and 315 lb. A set of five is short enough that breathing and pacing do not dominate it, so what the bar does on the fifth rep is a fair proxy for what it would do on a single — which is the assumption the whole method rests on.
Training loads from a 309 lb max
Programmes are written as percentages of the max, not as absolute weights. From 309 lb, rounded to the nearest 5 lb:
| Percentage | Load | Typical set |
|---|---|---|
| 95% | 295 lb | Heavy single |
| 90% | 280 lb | Doubles and triples |
| 85% | 265 lb | Sets of four to five |
| 80% | 245 lb | Sets of six |
| 75% | 230 lb | Sets of eight |
| 70% | 215 lb | Volume work, ten or more |
309 lb is 2x45 + 1x35 + 1x5 per side plus the bar — 305 lb loaded. Plate maths gets easier at this weight, because most of the jumps land on whole 10s and 25s. The bottom three rows of that table are worth rounding generously; the top two are where you want to be precise, since 5 lb at 95% of 309 lb is the difference between a single and a missed single.
The formulas behind this answer, and their limitations
The table above the fold is Epley (1985), Brzycki (1993), Lombardi (1989), O'Conner (1989), Wathan (1994), Lander (1985) and Mayhew (1992), each applied to 265 lb for 5 reps; the headline figure is their median. All seven assume a set taken close to failure with clean technique. At 5 reps you are still inside the fitted band, but conditioning is now affecting the result alongside strength, and the seven have begun to curve away from each other. They also under-rate strong, experienced lifters, who hold a higher percentage of max at any rep count than the regression average. The full account — the populations behind each equation, what a bounced rep does to it, and why we stop at ten reps — is set out on the methodology page. Warm up thoroughly and use safety bars or a spotter before going anywhere near 309 lb. This is a training estimate, not medical advice.