Problems with BBs feeding. Not mag spring or loose mag.

[AirsoftPleb]

Hey! Hi.....

So, if you saw the other post I made, I just played the Guns of Azerbaijan match on July 15-16. As soon as the match started I was having issues, first, I lost my buttstock (that someone found that god) but I noticed an issue of my gun just not shooting?
1) At first I thought it was the mags (brand new, never used before) but they are a high quality set. Also I pulled back the notch and all the NBA shot out, so I know that works!
2) next I thought my hop up wasn't pushing far enough to release the latch. This was disporven by the Bbs falling out everytime I ejected the mag.
3) next I thought the hop up was too narrow or got deformed but I realized I could shoot the gun upside down and that really confused me.

Next step I let my someone who also had a combat machine to try the mags and they worked perfectly for him. So to be something to do with my hop up I think.

NEED TO KNOWS
My gun is a G&G combat machine raider CQB. (Bought in like, 2015 but only used twice)
My mags are G&G 120rd polymer mid caps
The BBs were .20 Matrix High grade BBs
The hop up is stock, the gun is stock, I haven't made any upgrades.

[Dominum]

The mags are new, right? Did you load them as full as you could get them? Try loading only 80 rounds and see if they feed.

[AirsoftPleb]

it is the mags. I tried using my high cap that came with the gun and it worked fine.
Ill try loading less than full and see how that works. I was thinking about taking them apart and cleaning them.
Also at the match someone suggested stretching the spring out? That sounded sketchy so I was going to try a few other things before I resorted to that.

[Dominum]

The spring tension is likely too much, not too little. You stretch springs when mags are very very old and the tension is not enough to feed, which usually results in feeding to slowly so that it will feed in semi but not in full. What you have is too much tension. Heavier BBs with higher polish may help, but generally the mags just need to be broken in by using them not filled all the way.