Tm gbb mp7 Airtac hpa adapter not feeding properly

[MackT_1]

I recently got a tm gbb mp7 and I’m using the AirTac m4 hpa adapter and it works perfectly with my pts epm-1s mags feeding well and all, however after the first half of the bbs in the mag (90/170)  it starts to not feed properly and eventually it won’t feed at all even though there is still air in my tank and still 70-80 bbs left in the mag. Not sure why it’s happening and I haven’t heard about this happening to anyone else. So if you know about this or know how to fix it please let me know. Thanks