I do not know what tolerances CBC (Brazillian maker of Mag-Tech) applies to their brass. I randomally picked up on from a 16ga box & measured it with dial calipers. Length checked at 2.472", .090" shorter than 2 9/16". Dia at mouth was .725" & just ahead of rim was .740". Modern day SAAMI specs call for a minimum chamber dia of .732" at cone juncture & .005" per inch taper. By todays standards then a 2 9/16" chamber would have a minimum dia of .732" at forward end & .745 just ahead of rim seat. This shell dropped freely in both chambers of my 16ga Lefever.
When Lefevers were being built there were no SAAMI specs & chambers varied somewhat. Imagine if you will you have a chamber whose forward end ois only .730" in dia & with normal taper. Then check it with a gauge built to SAAMI "Minimum". With chamber having .005" per inch taper & being .002" smaller in dia than gauge it ill stop short by .002/.005 or .400" short. That would show the chamber being more than 3/8" short when it is actually only slightly under in dia.
Measure twice & measure everything before you "Cut" anything. My Lefever6 actually has 3" chambers by measurement. Are they original, I don't really know. I can however think of no time in its life it would have more likely to have received them than when it was built.
It is a post 1907 gun as has the '07 patent date. At that point in time chambers were still available cut to order in most any length desried in 1/8" increments from 2½" to 3" & to 3¼" in 12ga, with the 2 9/16" being thrown in for 14 & 16 ga's. Larger than 12ga still longer was available.
