The delta L problem (ΔL problem) refers to certain firearm chambers and the incompatibility of some ammunition made for that chamber. ΔL is a Commission Internationale Permanente (C.I.P.) geometric dimensioning and tolerancing definition for cartridge cases that are longer than the chamber they have to fit in. "Delta L" essentially means "difference in length". There is normally no cause for alarm regarding any cartridge designated as a ΔL problem cartridge, as the ΔL problem does not create a dangerous condition in the firearm in the rare event that ΔL problems are actually present.