After having spent more than half my life with a Colt 1911-A1 fitted with a 7 round magazine, I fail to see the disadvantage to carrying 10 rounds of 45 acp in the pistol? In earlier days we used to carry 2 extra 7 round magazines on our belts and never loaded an 8th round into the chamber on top of a fully charged magazine because that might have caused a top round jam.
Today, I carry a Glock Model G-21. That's 13 rounds in the pistol and 17 more rounds carried as backup inside an Arredondo magazine on my belt. That's 30 rounds in total! OK, shooting style and technique have changed; so, I'll grant that 30 rounds today doesn't equate to the same thing as 21 rounds yesterday.
Nowadays, a combat pistol tends to be fired, either, twice or thrice every time that it's used. Roughly speaking the total 30 rounds I carry, today, equate to the spare 14 rounds I carried yesterday. This means that today's different self-defense methods and pistol firing techniques have effectively reduced the greater amount of ammunition I'm presently carrying by more than half!
This being said: I, too, really like and trust my G-21's. All pistol ammunition performs, at best, only marginally. Still, with a longer barrel and larger heavier bullets my G-21's hit about as hard (and as often) as I could hope for out of any combat handgun.
Then -
Now -