GBB pistol loading issue

[Screw Loose]

Hi everyone, got a KJW full metal GBB M9 which doesn't seem to be loading properly, it fires every other shot however if I manually cock the slide it fires every time, is it just as simple as needing to be lubed up? If so what's best to use as new to the whole airsoft thing and not entirely sure what I should be using? 

Thanks in advance, 

Liam 

 

[EDcase]

Is it new?  Might be worth asking for a replacement...?

Work the slide back and forth by hand.  Does it feel smooth or catchy?  Keep working the slide holding the hammer down with thumb until it feels smoother.

Lubing would be a place to start. Plenty of vids showing how on Youtube.

Use 100% Silicone grease or spray.  (Don't use WD40)

Clean barrel but don't spray lubricant in there. (plenty of vids)

Check the air nozzle and feed arm underneath for signs of damage.

Compare to online images to make sure nothing is broken.

May also need to clean the magazine BB slot