It's true I've been focussed on looking at 8 rd. mags rather than 7. Maybe I'll get a couple of each.
The original mag capacity for the .45 Auto 1911 was 7 and is my personal choice for mags, but the 8 round capacity has become the more common mag in recent years. You need to pay attention to what you are buying, when choosing 7 rounders, since the most commonly marketed 7 rounders these days are for Officer/Compact size 1911's and they won't fit in your Government/Full Size gun. Be aware of what you are buying.
Another thing to realize is there are basically three lengths of 8 round 1911 mags. All things being equal, the longer tube will work better than the shorter tube.
Using the Chip McCormick (CMC) line-up as an example, since they have three different length 8 rounders.
1. Match Grade
M-MG-45FS8-Match Grade | Full-Size 1911, .45 ACP, 8 Round, S
- this is a flush fit 8 rounder. Flush mags were originally designed as 7 rounders, but with modified springs and followers, manufacturers were able to squeeze 8 rounds in a tube length designed for 7. Some work, some don't.
- these mags will likely be difficult to seat with 8 rounds in the tube and the slide forward.
- my personal opinion is if you want a flush fit 8 rounder, the only follower that reasonably allows that is the Devel (Shooting Star) follower primarily used in the CMC line-up of mags.
2. PowerMag
M-PM-45FS8-Power Mag | Full-Size 1911, .45 ACP, 8 Round, Sta
- a slightly extended tube length. The PowerMag and Wilson's 47D are the same length. They are a little longer than a flush mag, but still are 7 round mag tube length mags modified to hold 8 rounds. Wilson uses the same length tube in both their 7 round 47 and their 8 round 47D.
- these mags are also often difficult seat with 8 rounds and the slide forward, especially when new. They usually loosen up and allow comfortable seating with 8 and the slide forward.
3. Railed PowerMag (RPM)
M-RPM-45FS8-Railed Power Mag (RPM) | Full-Size 1911, .45 ACP
- This is an actual extended tube 8 rounder, designed as an 8 round mag and not a converted 7 round mag. The RPM is longer than the PowerMag. Wilson's ETM, Tripp's CobraMag, ACT-Mag, and a few others are of this length. If you want a reliable 8 round mag, you should probably choose a mag of this tube length.
- these mags usually seat with 8 in the tube and the slide forward as easy as a 7 rounder.