TM mk23 not firing right

[god84]

Hi all, I have the TM Mk23 with all the hadron mods and the like installed.

On my old ASG mags it was firing like a dream with the suppressor on or off.

However I bought two new STTI mags, that are apparent clones of the ASG ones.

It now doesn't seem to be able to last a full mag, every other shot dribbles out of the barrel. Its driving me crazy.