These are the rarest uppers and lowers Knight's produces. Knight's Armament SR-30 Pistol in .300 blackout w/KAC 300BLK LOWER, and the KAC 9.5" 300BLK upper with KAC heavy Buffer. Gun in pic has the SBA3 Tactial Armbrace installed.
$2478 for pistol, add $30 shipping = $2508 and add 3% for cards is $75 = $2583 shipped on a card
These come with Manual, Magpul panels, & KAC front and rear sights also. Transfers as a lower to your dealer, this way in the future you can build anything you want on the lower, pistols, rifles etc. Call Chuck 305 923 6560 TO order or for more details.
Upper Receiver Kit, SR-30 MOD 2 9.5" Barrel, M-LOK"P/N:32310
The SR-30 E3 Mod 2 takes advantage of the .300 BLK, offering a 9.5” barrel that is as capable as an 11.5” 5.56 mm SBR, for a significantly more transportable and maneuverable firearm. The QDC compatible Flash Hider will mount any of the KAC 7.62 mm QDC suppressors. The SR-30 has 99% parts compatibility with the SR-15, requiring only a dedicated barrel and muzzle device. Seamlessly transition from subsonic ammunition to supersonic with nothing more than a change of the magazine. 
Barrel: 9.5” (24 cm) 1:7 Twist, Hammer Forged, Chrome Lined
Caliber: 300 Blackout
Weight: 3.8 lbs (1.72 kg)
Length: 18.5” (47 cm) OAL

These come with the SR30 lower receiver.