Originally Posted by uv_halo
As for the T8-T9 series of guns, I don't know if I'd say 'over-engineered'. Just engineered from the beginning to be a spool valve relying on an air-through magazine (the T4 was for the most part, a re-housing of the T8/T9 guts).
I'd consider the T15 to be a 'next-generation' marker. PhantomDesigner claimed to be involved with it's development- here's what he had to say:
The inevitable FS jam is a function of the mag/breach design. Based on pics of the mag I've seen so far, I wouldn't hold my breath. Relying on a follower to hold a round in the breach is not the best way to go. In my opinion, you can get away with this if you're running a low-force, closed-bolt system.
As fragile as FS rounds are, I think it's probably particularly challenging to duplicate the extraction function of modern rifles (i.e. you get a jam, quickly pulling a lever to eject the damaged/unseated round) and chamber another round, without making the mess worse.
That would be difficult to duplicate as fs rounds have no lip for the extractor and they're fragile not nearly as strong as brass which can stand up to a extractor mechanism. I do agree about closed bolt, not just for fs rounds but for magfed markers in general.