The body style was more modern than the M series.
They've been replaced by the L and the M series.
In 1902 these stamps were withdrawn and replaced with the "A M" series.
The range was subsequently expanded with the M series and G series.
The last in the M series was the M-11.
The new M series took the place of KB models in 1970.
One shift in the design was the number of machine-guns which was much lower than on the "M" series.
The standard ammunition load was lower, only around 600 rounds, compared to 3,000 of the "M" series.
Quicksilver's disappearance is explained in the Son of M limited series.
The M series were precisely detailed with a wide range of offerings.