Quote Originally Posted by TriumphRat675 View Post
What kind of teething problems did the AK74 quads have? Were they a similar design? Glancing at the patent (with all my years of mechanical training I received with my liberal arts degree) it looks like those spring-loaded bails might be susceptible to getting clogged up with debris.
They had durability problems and started having reliability problems with age (springs maybe?). I wouldn't expect either from Magpul. Not sure if the Ruskies got theirs sorted out. Its been since I've looked and info is hard to come by. One advantage the 74 quad has over an AR15 quad is the 74 mag is able to stay quad stack almost all the way to the top due to a lack of mag well.

Quote Originally Posted by Boss Hogg View Post
If it's close, does the US Patent Office grant patents to a design that's very similar to something that's already been released somewhere else in the world? (The EU patent office does not IIRC)
74 mag is a bit different. Even if they were filled to the same office I would guess each would get their own patent.