I noticed yesterday that when I raise and lower the muzzle of my Kimber the chambered round slides back and forth. Also, if I retract the slide a bit I can slide the round back and forth with my finger. I've never noticed this before.
I dont think I have ever heard that question before this. I have four 1911's just lying around and I checked each one of them and all I can say, is mine dont do that. Now keep in mind that mine are all COLTS.
I really dont what to tell you, but I would start with an ammo check, make sure you try factory stuff, and reloads too. Find another Kimber and try it, I really dont have a good answer for you, but I bet someone here will. Mic the chamber, send it back to Kimber but do something to clear this up.
I'm pretty sure that whatever it is it happened at my last range session. I've got 300 rounds through this pistol and I haven't noticed this before. I think it's the extractor, personally. It's like the extractor is now sticking out too far.
Off the top of my head, I'd tend to agree with you on the extractor. It should hold the round in place against the breech face. If it lacks enough tension and is not holding the round, the round could move like you said.
what you have here is a longheadspace/long hood situation. You have a very loose chamber. Not going to be a problem probably but it would never do in a match gun. I'd also check the extractor tension. Take the slide off the gun and slide a loaded cartridge up under the extractor so it's positioned just like when it's chambered. You should be able to hold the slide horizontal and the cartridge should stay in place. I suspect if you can hear the round rattling back and forth in the chamber that you have a loose extractor.
The round stops going forward in the chamber when the
bullet hits the rifeling. (unusual)
the case mouth hits the front of the chamber
or the case is stopped by the extractor. (if the case is .880 for instance or the chamvber is long)
You need room from the bolt face to the extractor hook (about .065 works well) to allow the case to come up the bolt face. The bullet is already entering the chamver so the round is coming up on an angle. the bottom of the extractor needs a slight radius to allow the rim/grove to push the extractor out of the way and not stop the rim from going up past the extractor. The back of the hook should also not be sharp at the bottom so it does not dig into the case.
I "think" your all correct that the extractor has little or no tension.
Tony I would have agreed with you until recently. One gun had a chamber that was .922
deep and it shot under 2" at 50. I was shocked! and One barrel came from the factory with a chamber that was .930 and shot a best group from a barrel fixture at 50 that was an unbelieveable .5 6 shots! I would have never guessed. (note these were both in super)
I've seen that before on a couple of guns, and they were very accurate and had no problems at all. Maybe there is little extractor tension, but as long as the pistol operates fine I think there's no really no need to change this. In my limited experience nearly all 45 ACP cases are a bit too short, so they won't headspace in the front of the chamber but rather are being held by the extractor in a somehow floating position, depending on the diameter of the chamber and the loaded round. All revolver rounds "float" in their chambers, sometimes even shake a lot, and their accuracy is more than fine.
Headspace for the 1911 is 0.008" to 0.012". If the loaded cartridge moves move than this when the gun is in battery, then you have a headspace problem. If so, then get it fixed as quickly as you can. Excessive headspace usually spells trouble for the gun and the shooter.
If the cartridge moves at all after it has engaged the extractor hook, then the extractor tension is too light. Follow Tony Gattuso's directions and see. Increase the tension until the extractor holds the cartridge in place by itself with the slide removed from the frame.