It will lift 0.28 stock no problem, if its not its because the bucking is dirty or worn out.
Buckings rely on friction to create backspin, so if they are dirty or oily this reduces the grip, which in turn reduces the backspin possible.
Thats why i dont like Maple ones as they are the least grippy rubber substance ive ever come across - another subject anyway.
Stock TM buckings are great, funnily the Maple Omega nub works very well in the NGRS.
Make sure to use quality BBs, keep them and the mags clean, swab out the barrel and bucking periodically with the tool provided.