I'm new to this forum but I thought I'd jump in. The Wilson 7 and 8 rounders are the same size externally as long as the same size base pads are used for both. The difference is in the followers. If a standard, full sized 1911 magazine such as the 7 rnd colt, 8 rnd shooting star or power mag fits flush, then so will the Wilsons. Wilson makes a ten round mag called the Bureaucrat which hangs out below the frame an inch and a half or so on the full sized 1911. Some people like the 7 rnd Wilson for an extra edge of reliability in a carry gun. I've always shot the 8 rnd mags and had complete success with them. It does take more effor to seat an 8 rnd mag than a 7rnd, but you could always just load 7 in a mag intended for 8 if that bothers you. Hope this helps.
Wilson's Officer length 7 round mags are shorter than the Government model 8 round mags. Wilson sells an 8 round Officers mag, which is the standard 8 round mag with a different base pad than has an extension up the front, to prevent over-insertion and provide a pinky rest.
I think that was the comparison Juggernaut was looking for.
Sorry, I don't have any pics of my Ultra CDP with a Wilson 8 round mag in it.
To all of you who answered, thank you. That picture told me everything I needed to know. I'll stick with the 7 rounders for carry. I have a Compact with the Shooting Star Mag, and I've been lucky with no problems. Wilson's will go into my Ultra CDP though, just because...