.223 Wylde AR Upper Short-stroking problems

[caleb90]

hey all. im a newbie when it comes to ar 15s. my first one is my 6.5 grendel built from ground up by myself. i recently bought a cheaper 223 wylde upper from cbc industries and i cannot get it to work. my grendel is a 20in bbl with rifle gas system adjustable gas block turned out 3/4 with a carbine buffer system. shoots like a dream. this new upper is a 20in bull barrel with rifle gas and non adjustable gas block put on the same lower. when i got it i cleaned lubed and check every thing over. loaded 10 rounds in mag and 8 out of 10 short stroked and didnt pick up next round. brought it back in took gas block off checked the ports and marked the port locations put it back on to make sure the ports were centered. took bolt back out checked gas key and gas rings and looked for any thing rubbing wrong. all looked good, took it back out loaded 1 round at a time in the mag and it still wont cycle fully. brought it back in yet again tore it down yet again. verified barrel port size and its location from the barrels shoulder, checked gas block port location from its shoulder checked for leakage and all is good. ran out of day light so will have to test it this weekend. is there any thing i can be over looking? help much apreciated thanks!