People are always interested in how tight a barrel locks up. Most people really dont care about barrel unlock. While lockup is very important for accuracy. Where a barrel comes to rest at unlock is equally important to ensure the pistol stays reliable and doesnt have a failure of barrel, link, slide stop or even frame.
I worked on a stock 1911 today and it was typical of most off the shelf 1911 and 2011 pistols. Almost everyone that has come accross my bench has had improper unlock. Even most of the so-called factory custom guns havent had the proper unlock.
So how should a barrel come to rest after the pistol is unlocked??? Well, the vertical surface of the barrel feet should impact the vertical surface of the frame. Almost all of the ones i have seen come to rest on the frame horizontal surface and the barrel feet horizontal surface. The main problem with this is that the only thing stopping the rearward motion of the barrel (which is most of the energy) is the slide stop and link. Eventually one of these will fail.
Pic of barrel and Frame showing horizontal surface impact
So to fix it, we cut the horizontal bed of the frame down to allow the barrel to drop farther and subsequently move farther to the rear. Once you do this however, most modern ramped barrels will then impact the inside of the of the frame rails. Again this is not stopping the rearward motion of the barrel. So, we also increase the 45 degree chamfer on the inside of the frame rails so the barrel may drop far enough to allow it to impact the vertical surface.
Pic of frame cut for clearance
Once we get the vertical surfaces to impact, then we tune how they interface with each other. It is important to have nice even impact all the way across and most of the way down the feet of the barrel. If this isn’t achieved, then we risk shearing off the feet of the barrel.
Pic of proper vertical feet impact
I worked on a stock 1911 today and it was typical of most off the shelf 1911 and 2011 pistols. Almost everyone that has come accross my bench has had improper unlock. Even most of the so-called factory custom guns havent had the proper unlock.
So how should a barrel come to rest after the pistol is unlocked??? Well, the vertical surface of the barrel feet should impact the vertical surface of the frame. Almost all of the ones i have seen come to rest on the frame horizontal surface and the barrel feet horizontal surface. The main problem with this is that the only thing stopping the rearward motion of the barrel (which is most of the energy) is the slide stop and link. Eventually one of these will fail.
Pic of barrel and Frame showing horizontal surface impact
So to fix it, we cut the horizontal bed of the frame down to allow the barrel to drop farther and subsequently move farther to the rear. Once you do this however, most modern ramped barrels will then impact the inside of the of the frame rails. Again this is not stopping the rearward motion of the barrel. So, we also increase the 45 degree chamfer on the inside of the frame rails so the barrel may drop far enough to allow it to impact the vertical surface.
Pic of frame cut for clearance
Once we get the vertical surfaces to impact, then we tune how they interface with each other. It is important to have nice even impact all the way across and most of the way down the feet of the barrel. If this isn’t achieved, then we risk shearing off the feet of the barrel.
Pic of proper vertical feet impact
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