Mine works great. I keep mine oiled wetter than my Glock and I use Remington Golden Bullet 525 bulk pack, which is 36g HP that runs I think 1280 fps.
Make sure you use high velocity, not standard velocity and not hyper velocity. I think Remington makes a variety of these types. You want the Golden Bullets.
Maybe buy some Mini-Mags, which are usually regarded as best quality and most reliable, and see if it jams using those. If the kit is clean and oiled, you shouldn't have a problem.