CM raider strange feeding habits

[Cerbera]

Hi all,
Could use a little help with my CM 16 raider. Actually it's not mine anymore, I gave it to a friend but it's been behaving strangely recently. I overhauled it before giving it to him and the gearbox is sounding smoother/better then ever!
However it "dry fires" the first 8 rounds or so of every mag I put in it. I've tried 6 or 7 different makes of M4 mag and they all show the same symptoms.
I tried loading each mag with less BB's but that wasn't it either. I gave him a couple of real magpul 120rds p-mags that were the best fit in the magwell but they too are misbehaving now.
When the BB's do decide to fire they fly straight with very little spread. Excellent actually! Any ideas would be appreciated.
I just put a TM rubber and a strengthened tappet plate in there too, it was doing so well! Really annoying.
thanks in advance.


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