Reloaders measure case length to ensure that the case is still within SAAMI tolerance. If a case guage indicates a case is too long, it should be trimmed to correct length before being reloaded. If a case is withing SAAMI tolerance, but the bolt is still difficult to close, a headspace guage may be required to determine headspace tolerance. Cartridge overall length is also important to ensure the ‘jump’ from bullet to rifling is appropriate. This can be a significant issue for accuracy.