The pistol is not at fault, it's the clip.
The spring in the clip has more pressure than the plastic feeder tube at the top of the clip can endure.
After a while, the feeder tube gets warn prematurely from the excessive spring pressure, and it starts double feeding or worse.
I've spent many hours figuring out the cure for this problem.
First of all, real 1911's hold 7 rounds, and these are replica's, so why not load 7 or 8 rounds, and make it more realistic ?
I've found that if only 7 or 8 bb's are loaded at a time, the pressure on the feeder tube is alot less than if you load 18 bb's, and I believe the feeder tube can handle the pressure involved with 7 or 8 loaded.
If you've been loading 18 bb's since the pistol was new, and the jamming has gotten worse over time, try loading 7 or 8 and see if that cures the problem.
If it still jams, then the damage is done, but all is not lost.
What you can do at that point is remove the spring retaining plate on the bottom of the clip, remove the spring, and cut 2 inches off the bottom (larger end), then reinstall.
Now your pistol with operate dependable, even with 18 bb's, however the auto lockback (when the last bb is fired) will not function.
I now have 2 clips with shortened springs, and they work great.
With any new clips, only load 7 or 8 bb's and you should never have any problems as far as I can tell so far, but im still testing that theory.
So far i've shot alot of rounds, and havn't had a single jamming issue with either of my 2 new clips.
So we have 2 options, 18 rounds and no auto lockback with the clips that have shortened springs, or 7 or 8 rounds with the stock clips,and the pistol fully functioning.
There is absolutely nothing wrong with these wonderful KWC made 1911 replica's, but the clips would be better if they had better quality plastic or even better, metal feeder tubes. I hope this helps alot of people experiencing problems with their KWC made 1911 blowback pistols.