Product description doesn't mention only 29-round capacity.
So, I probably should have checked reviews before I bought, but in fairness, the product description does not reference that the floorplate drops your magazine capacity from 30 to 29 rounds. Technically, you could try to force a 30th round in, but you'll have a tougher time getting it in, and then your magazine won't feed properly. Kind of like if you try loading a 31st round in otherwise.
You could try to cut one or two coils off the mag spring, but that'll cause issues if you ever (for whatever reason) want to remove the floorplate and go back to the original one. If you intend to use these for competitions or duty, I'd skip this product. If you're just going to use them at the range, or really want the weight savings from aluminum mags like D&H's (which is what I tried these on) and are willing to mess with the spring, they'd work ok. But otherwise, I'd just stick with the PMAG version, which works fine and lets you load all 30 rounds.
