Jim, not owning a 1911 9 mm or anyone that does I went on the assumption that the mags are 10 round capacity so hence the need for a Barney mag. If the mags hold more than ten rounds no need for the Barney mag and pardon my ignorance.
The "natural" capacity of .38 Super and 9mm G.M.s is nine.
The same trick followers and skimpy springs that make it possible to squeeze in eight .45s will let you load ten .38 Supers. It does not work quite that well for the short, tapered 9mm. Reasonably reliable ten shot 9mm single stack magazines had to wait on the slightly protruding tubes seen on current Wilson, Tripp, and Metalform magazines to allow a little more spring space.
I always had very good results from 9 shot Metalform Super magazines in 9mm guns. But that did not work out well for other brands or any ten shot. I THOUGHT a Tripp Super magazine was doing well with 9mm until this past Saturday when it tied up the gun thoroughly.
Right now I am shooting ten round 9mm Tripp Cobramags and Wilson ETMs. I have some Metalforms that are also doing well, but the first batch I had (lost in The Incident) required rebuilding after about a year of use. We'll see about these.