Ok, so I’m new on here. I’m not gonna ramble on. Anyway, purchased the Sub 2000 Brand New from a gun shop last week. Did allot of researching about it, ended up buying about 95 percent of ALL the MCARBO UPGRADES, without even shooting this rifle once. Today I finally got to test it out at a indoor range. My Sub 2000 was still Factory Stock. I got to fire off about 40 rounds and then it stopped firing. I tried different magazines, messed with it numerous times for about 20min. Then figured out, for some reason I now had to pull the trigger TWICE before it would fire!!! Any idea whats causing that ??? Thank you for any replies.