While I stand by the probability that it is likely the extractor,some other folks have made some good points.
I have to agree that tuning the extractor may not be the best first step.
If the gun will run with the 230 gr hardball it was designed for...well,its the same extractor...and its running.
That is the least invasive first step.
Next,sure,try a standard,good quality magazine.Seven rounds is what it was designed for,and seven have the best rep for reliability.That 10 rounder might be a good reload,but its not a holster magazine.You need at least one,and at least three is better.
I do not suggest trying a used magazine.
Now,here you COULD run into a little bit of an issue with magazine spring tension.The mag spring plays some part in the round scooting up the bolt face.
And,of course,if you change one thing at a time,you learn something.Change two things at once....what do you know? It could be x,it could be y,or it could be x+y. Now what?
It is also valid that your life and death handgun may be better served by a professional gunsmith than your DIY efforts.What is routine easy for him may be excruciating and expensive by the time you get it right.Your smith will not charge much.
With all due respect,as I observe the level of skills in our culture today...probably 7 or 8 out of ten,my guess,should not even try to remove the extractor from their 1911,much less tune it.
The 30yrs I spent in the machine shop....well,I have to remember,not everyone has that background.
An aside,if you do get your extractor sweetly tuned,Well,for a 1911 or other controlled round feed pistol,do not !! drop a round in the chamber,then drop the slide to single load,or load mag plus one.
Always feed from the mag up under the extractor.
Forcing the extractor to snap over can de-tune or break it.
