New pistol build, FTE

[LMarshall73]

So, I finally finished my second AR pistol and took it to the range yesterday for a workout. First round failed to extract resulting in a double feed. Cleared the malfunction (pulled the charging handle back, let the bolt slam home, pulled the handle back again and the case extracted - nothing out of the ordinary with the case), chambered a fresh round, hit the forward assist for good measure. Fired and another FTE. Cleared the same as previously mentioned. Chambered a third round, pulled back on the charging handle to ensure that the extractor was grabbing the case (it was), used the forward assist to reseat the round, fired, FTE. Specs of critical componenets below:

Rock River Lower/LPK
Spikes Pistol Tube and buffer
BCM upper
DPMS Kitty Kat barrel w/Levang comp
Spikes M16 BCG

Ammo was Lake City SS109

I do have a BCM Extracor spring upgrade kit I could install, but wanted to see if anyone had any other recommendations first. Ideas?

[Azrael2004]

I would add the extractor upgrade or at least an o-ring. It's amazing the woes a little o-ring can overcome. Inspect the extractor hook while you have it out.

If it still does it then I would explore further.
If you fire a round with an empty mag in the rifle does the bolt lock back?
Is the extractor tearing through the cartridge rim, rough chamber, signs of overpressure cartridge.........?