Let's face it - almost everyone who came along after John Browning "stole" some design features.

The Glock has, essentially, the operating system of the Austrian 1907 Roth-Steyr, the tilting barrel locking of the Browning High Power, the use of the barrel hood for locking instead of lugs on the barrel and corresponding machine cuts in the slide from the SIG Sauer 220, the polymer frame of the Heckler and Koch VP70Z, the high capacity magazine of the Browning High Power, the firing pin safety of the Walther P4, and I guess I could go on and on.

The "feature" which was the subject of the Glock v. S&W lawsuit is the feature described in the Glock patent as the "positive guide means," which, if I understand the documents correctly, is the "shelf" on the left side of the Glock frame which prevents the cruciform sear from dropping out of engagement with the lug on the firing pin until the moment of firing, which Glock refers to in its literature as the "drop safety" (since it prevents the sear from "dropping" out of engagement with the lug on the firing pin safety before the moment of firing).

Just why it is called a "positive guide means" in the patent documents is a mystery except that engineers sometimes call a part one thing when designed and another thing when it is presented to the public.

The fact that Glock felt it had a legal claim when you look at the inside of the two pistols was a mystery to me, but then again, I am not a patent attorney, nor am I the inventor of the Glock pistol. I suppose if I were Gaston Glock, I might think my idea had been infringed upon also.

While parts may not interchange, the way the two uppers work is identical. That said, there is nothing in the upper that is really so unique as to deserve a patent.

The lowers on the Glock and the original SIGMA 40F just did not look enough alike or operate the same to my amateur eye to justify a settlement, but sometimes settlement decisions are made based upon other factors (cost of the suit, etc.).