I'm trying to decide if I want an mpx, but I am thoroughly confused. I think I have narrowed it down to the mpx K 4.5 barrel, but now it seems there is a mpx copperhead 4.5 that also has the improved trigger. Other than the rail on the front, is there a difference between these (the copperhead 4.5 seems to be about 200 less than the K). Sights do not seem to be included. Does anyone know why the 8 inch barrel was discontinued?Thanks

My understanding is the Copperhead came from a Sig contract where a customer wanted the MPX but in a more compact configuration. Monolithic upper, shorter 3.5" barrel, and the newer funky looking grip that is not widely available via aftermarket.

I don't care for the monolithic upper or the non-threaded shorter barrel on the Copperhead. I prefer the modularity of the MPX-K and happened to come across a new one for a song.

Regarding the 8in barrel, it seems to be more of supply / demand thing. The extra length doesn't do much for 9mm ballistics and the trend seems to be shorter barrels across most of the mfg who make PCC's.

EDIT: Looks like you're referring to the newer black one that has the Timney trigger, 4.5in barrel, and also has mounted flash suppressor instead of one integrated into the barrel. I guess it comes down to the aesthetic you want for the price you have for both. If you mount a suppressor on the Copperhead it's going to just stick out. With an MPX-K on the other hand you can pickup any number of very good Sig and aftermarket handguards to make a suppressor look more integrated.