The references I have show die #126 as "9 MM rifle", anyone have any idea what cartridge it may be referring?
The die is 1.82 overall length and my imprecise measuring to the beginning of the neck shows about 1.01. The neck sizing area mikes 0.371.
Another oddity is a seating die # 116 which should be 7 mm Mauser but it is stamped also with 6.5 mm and appears to be typical Ideal stampings. The seating stem is #438 which would be correct for several .225 boolits but the stems get changed around so much that is meaningless.