Thread: Forbes 280AI Load Development

Further to the previous post and some more info specifically for @Feebz' Forbes in case he is interested, putting his results into QuickLoad along with the other powders being mentioned. This identifies that the slower powders do produce more velocity at a fixed moderate peak pressure which may be what the book data was indicating. Predicted for 50kPSI peak:

2225, 66.5gr, 2850 ft/sec, 10% compressed (if achievable)
2217, 61gr, 2800 ft/sec, 2% compressed
2213sc, 58gr, 2725 ft/sec, 95% fill

If loading for 60kPSI peak then the following is predicted, the double-based N560 also included:

2217, 64gr, 2950 ft/sec, 7% compressed (if achievable)
2213sc, 61.5gr 2900 ft/sec, 1% compressed
N560, 62.5gr 2980 ft/sec 1% compressed

So if wanting to try for more velocity than the 61gr of 2217, then 2213sc, N560, or similar burn rate powders are recommended, bearing in mind that the above figures are from a simulation and come with no guarantees. If preferring to stay with 2217 and happy to work with heavily compressed loads and accuracy remains, then the prediction is that there is still quite a bit of room to move.