1911 experts - 9mm vs. 45 ACP pistol width the same?

[wsr]

Not my experience. I just picked up a used RIA 9mm 1911 this week (really like it) and it really doesn't fit any of the other 1911 holsters I have. It's too fat at the barrel end to fit into the Comptac that I use for a Springfield Range Office. (It might if i totally loosened the adjusting screws but then the Springfield would be flopping around). It fits sloppy into a Fobus holster that I use for a Colt, but would fall out if turned upside down. I have a Serpa that fits a Kimber SSII fine but I have to push hard on the RIA to get it to go in and get caught on the retention tab. I'm actually kind of bummed on the lack of commonality in holster fit.

That's not a caliber issue that's a manufacturer issue

[JohnS624]

Not my experience. I just picked up a used RIA 9mm 1911 this week (really like it) and it really doesn't fit any of the other 1911 holsters I have. It's too fat at the barrel end

Does it have a rail or extended frame?

[pscipio03]

Aside from some one-offs, the measurements should be the same.
1911 on top is a cheap-o Tisas 9mm; one on bottom is a customized Colt 70 Series 45.
Just a quick measurement behind the barrel hood shows widths.
One of the reasons why 9mm 1911s tend to be a little more finicky- the pistol was designed and built around a different caliber.

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[Supercharged1]

No rail.

[Supercharged1]

Regarding caliber not being the issue, that's true. Probably more correct to say the when it comes to holsters for 1911's in general, one size does not fit all.