Mine seems to like xcr pistol mags but not the grey lar ones you are right about the shoddy looking mags it came withI took my T97 out for the first time yesterday. Put 100 rounds of American Eagle FMJ through it without one hiccup at all. The rifle preformed flawlessly and was just plain fun to shoot. My gas setting was on 1 from the factory. Hardly any recoil and pretty good accuracy from 50 yards offhand....about 5 inch groupings, which is good for me. I was using DH mags and they worked fine in the gun, fed nicely and dropped free. I didn't even try the magazine that came with it as it looks fairly shoddy to me, the huge rivets and a bit of rust. I've yet to strip it but as others have said it seems fairly simple. A scope rail is on the way and I'm going to try a dot on it next. All in all I'm very happy with the rifle and can't wait to get it out again.
I have also had a few fail to feeds with the bullet itself being pushed back into the brass. Like you said, gets better as you break in but still get the odd one after about 250 rounds through it. I've been shooting chinese surplus and AE. Me and a couple buddies got all our STANAG/AR mags together and gave my T97 a torture test. 21 mags with 5 round per mag, 105 rounds as fast as I could do them with the many mag changes but she handled it well FTF once only and was a smoking piece at the end for sure. Its definetly a higher end chinese weapon for sure. The polymer/plastic seems to be decent as well and everything looked good when stripped except a bit of the parkerizing/finish on the barrel was shoddy in places, light or discolored. Overall alright gun for the price and if you gotta own a bullpup why not this one.
Lot of Polymer on it?