Shortfuse: I have not tested my own ability of shooting Glock vs 1911 for accuracy.
What I CAN tell you is that twice I entered an informal NRA Bulls eye pistol match at a local range and won both times with my Glock 21.
I say "informal" because we each just did 2 slow fire strings (10 shots each) at reduced targets, 4 timed fire, and 4 rapid fire strings (5 shots each) IIRC with only one handgun. (Not the once with the .45, once with the .22LR, and once with something else)
OK, with that in mind, I won by a substantial margin each time I entered, shooting against custom Para-Ordnance, STI, and other expensive 1911s.
Let me make myself perfectly clear
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that the main reason I won was I dry fired bullseye style every day for a week before each match and before the first one read the article in American Handgunner about this kind of match at least once a day for the whole week. In simpler terms, I submersed myself in the bulls eye mentality for about 8 days for each match.
ALL other competitors did not have a bullseye attitude. I actually single loaded my G21 for the slow fire strings so I would be holding the minimum amount of weight at arm's length. I gave my arm a break between shots, also. I even found a good stance and didn't move my feet for the whole slow fire string. NO, I'm not a bulls eye expert, just a Reasonably Knowledgeable Individual, but it payed off at these matches.
Having said all that, Glocks are less tolerant of bad shooting technique such as squeezing the grip or jerking the trigger than 1911s.
When it comes to practical or combat accuracy, I don't see any difference in Glocks vs. 1911s at realistic distances. I DO see that better shooters have tighter groups so mainly it's the shooter, not the gun that counts.
Edmund