#RotaryBolt

What was the first double-stack .45 ACP handgun in the world? Well, Springfield Armory Inc might have you believe it was their XD (originally called the HS2000 – and then and now made in Croatia), but more plugged in gun nuts will point to the Para Ordnance P14-45 wide-frame 1911 pistol. It turns out that double stack .45s go back before then… WAY before then. Meet a gun that never lived long enough to get a real name, a double-stack 15-round .45 ACP handgun designed by Colonel Isaac Newton Lewis:

We introduced you to the concept of locking in a previous one of our 201-level posts on how firearms work, and today we’re going to talk about what has become the most common locking mechanism for rifles: Rotary locking. If to lock an action, you need to create an interference between the breechblock and the barrel, one of the most intuitive ways to do this is the same way a barrel bolt latch works.

In the second of our 101-level discussions on firearms operating mechanisms, we mentioned that firearms may have what’s called a locking mechanism, which prevents the separation of the breech and barrel during the high pressure ignition of a round of ammunition. For 101-level posts, we’ll mostly note whether locking occurs or not and nothing more, but today’s 201 post will begin to talk about locking mechanisms in detail. First, we need to understand that there are two different things meant by the term locking. The first is the more proper understanding of a fully locked breech which must be opened by some external force, but the second is often referred to as “locked” as well, even in some professional literature. This second use is more properly called half- or semi-locked, and describes locking elements that are used in retarded-blowback mechanisms.