My .357 was exactly the same. There really isn't a chamber as we normally would define it. When I lengthened it for .357 Maximum brass, the reamer only removed a tiny bit of metal in the long freebore, leaving a small lip.
I did try several Max cases trimmed until they fit the factory chamber. Accuracy improved somewhat, but at that point, it began to look silly to trim cases, when ten minutes with the reamer and some cutting oil would allow the use of full-length Max cases and full-power handloads.
Even after lengthening the chamber to .357 Maximum, there is still so much freebore that I can seat a huge 245-grain Lyman cast bullet that was originally designed for the old .35 WCF cartridge all the way out so that the lube grooves almost show, and still not touch the lands.
Yup, NEF oughta get a new chamber reamer . . .