The modern thin-walled forged-steel design made feasible shrapnel shells for howitzers, which had a much lower velocity than field guns, by using a larger gunpowder charge to accelerate the bullets forward on bursting. The ideal shrapnel design would have had a timer fuze in the shell base to avoid the need for a central tube, but this was not technically feasible due to the need to manually adjust the fuze before firing, and was in any case rejected from an early date by the British due to risk of premature ignition and irregular action.