Cartridge Overall Length can be critical. Generally speaking, the pressure increases when the bullet is seated deeper (there are exceptions), but you should know this from reading your manual. For example, there is some reason to believe that a number of the many 40S&W Kabooms have been caused by bullet setback; the lawman loads and unloads his pistol many times, with the result that the bullet is pushed deeper into the case. The impact of the bullet slamming into the feed ramp has caused setback and the Over All Length is shorter. The reduced powder space behind the bullet creates an overpressure situation when the cartridge is fired.
A lack of planning on your part does not necessarily constitute an emergency on my part.