Directly from Wikipedia:
The Panther was the first prototype semi-automatic marker designed by Tom Kaye of Airgun Designs in 1988. Since it was only a prototype it was never offered to the public. The design was sold to Direct Connect, but was never manufactured. AGD bought the design rights back in 1989 through a non-performance clause in the original contract. The blow back design was deemed to be too primitive (because pump markers changed in 1988, they got removable barrels and quickstrip pins) so a second generation prototype "P2" (for Panther Prototype Two) was developed. This second design was also a blow back, and had many problems. It was decided to give up on blow back technology and re-engineer the entire action into a "blow-forward" design. This eliminated many problems inherent in blow-backs, such as their dependence on full, constant operating pressure in order to cycle reliably. This hearalded the beginning of the Automag design which went through two revisions; P3 and P4. The P4 design was released to the public in 1990.
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