But would you touch a kid with a glove?
I'm surprised it took them that long.
Only if willful infringement is proven. Several years ago, the company I worked for was the defendant in a patent infringement case. In the discovery phase, an email from my boss was found that acknowledged he was aware of the plaintiff's patent, but was going to move forward anyway. The jury found willful infringement and awarded treble damages. The "joke" was the court found the actual damages to be about $14K - so treble damages were about $42K. This was nothing compared with the legal fees - which were the better part of $1M.
FYI - the Magpul patent-in-suit 8,069,601 was issued in December 2011 (filed in Jan 2009).
The complaint alleges the defendants literally infringe at least the following claim:
1. An ammunition magazine comprising:
a. A casing having a mostly rectangular cross-section with fore and aft sides and two longer lateral sides and first and second open ends, the casing further comprising:
i. two guide rails extending a length of the magazine, each one situated along the lateral sides in an interior of the casing, the guide rails extending at least mostly to the first open end and each presenting a flat forward surface, roughly parallel to the fore side; and
ii. a ridge, centrally located on an interior side of the fore side and extending to a terminus located at least mostly, but not entirely, to the first open end;
b. A follower residing within the casing, said follower further comprising:
i. A follower platform with two opposite tines at fore and aft positions and extending generally perpendicularly and distally therefrom;
ii. Two side fins situated to interface with the casing's guide rails;
c. A floor plate capable of interfacing the casing at the second end; and
d. A follower spring residing between the follower and floor plate; wherein the tines and the side fins limit rotation of the follower within the casing.
This is pretty broad to me, and frankly I'm surprised such a broad magazine claim could be issued as late as 2011. The patent issued after only a single office action, which in my experience is "faster than usual". Doesn't mean it isn't legitimate or anything like that - this depends a lot on the examiner and how competent, nit-picky, and experienced they are. In cases like this where there are multiple defendants (even if competitors), they often form a joint defense team to pool costs and share prior art research. If they think they have good enough prior art, they can file for patent reexamination. In that case, the patent office can affirm the patent or invalidate the patent based on the findings and their judgement. This will likely take a while to sort out, and it is unlikely this will go to a jury trial.