When theres delays theres reason. My guess? Over-zealous and overly ambitious. FX has a great business model. Rinse, repeat, Bell, Rinse,repeat, Whistle, Rinse, repeat. Crazy how much hype FX can build up for things that take a year + to release with little criticism, yet when any other company does similar they generally never hear the end of it and receive all types of hate... :shrug:
If I were to guess, and I am just guessing, there is a reason for this: FX's pace of new releases is comparatively relentless and they exist out on the cutting edge. They also are reliably late, but only fashionably late not stupidly late. Contrast that with the Umarex Hammer which has been "just a few months out" for several years now. And as much as we think of FX as an airgunning behemoth, I'm betting they're actually a very small company comparatively speaking in terms of number of employees, cash flow, etc.
Regarding why what seems so simple has taken so damn long to show up, I've got two hypotheses.
1) There is a lot more mass to spin in a slug, so they probably need deeper rifling to bite effectively. Given how FX makes barrels, this is probably a lot more challenging for them than a company which makes barrels via button rifling, cut rifling, CHF, etc.
2) They're probably not expecting it to be a high volume or high profit product, and so the little fun side development projects often are shoved aside in favor of things that'll generate real cash flow for the company. In the case of FX specifically, they're showing a variety of signs of strain when it comes to manufacturing capacity. Take the Dreamline for example. By and large it is just a hodgepodge of other parts they're already manufacturing with some clever integration. That doesn't make it bad, far from it, but it means that dev. time probably isn't what is slowing it down, it is probably machine time at their manufacturing facility. If they're struggling to keep up with demand on whole rifles, methinks producing slug liners for us freaks is just not the priority.
Of course none of this is meant to make excuses. I'm generally of the opinion that companies should meet deadlines and deliver what they promise, but FX seems to be run by the Axelson cult of personality and part of his creativity is his optimism. Certainly nobody else is stepping up to do what they do, so I guess that adds me to the list of people who will "just put up with it."