geometric dimensioning and tolerancing definition for cartridge cases that are longer than the chamber they have to fit in.
conforming maximum sized cartridge (a cartridge with external dimensions larger than specified by the Commission Internationale Permanente), use of that ammunition in the firearm may lead to chambering and/or feeding problems in the shoulder area of the chamber, or other headspace issues.
A precondition for such a comparison is that the shoulder angles are identical, since otherwise shifts will occur, which are not recognizable at first glance.
This condition results from the fact that the length of the junction cone becomes longer if the diameter becomes smaller.
On the other hand this oversize is a major problem with break action and combination guns, which are less common in the United States than in Europe, because correct cartridges cannot be loaded into correct weapons in the event ΔL was not considered during manufacturing.
For this reason, the chambers of break-barrel arms are generally manufactured with reamers that take ΔL into account.
[1][failed verification] Generally bolt-action and break-barrel hunting rifles in C.I.P.-regulated countries are not cut to the minimum C.I.P.
The arms manufacturer SIG Sauer brands Blaser and Mauser are however known for hammer forging tight (but still C.I.P.
The table shows the popular .30-06 Springfield cartridge family with ≈ 0.15 mm (0.0059 in) theoretical chamber length shortage to be the most prominent ΔL problems candidate.