[gbw]

This pistol has a habit of doing this every couple hundred rds. or so. I'm going to start with the FP stop and extractor, but if anyone knows better I'd love to hear it.

Gun is a Colt CE slide, Essex frame, Kart NM bbl., and nearly all other small parts are Ed Brown.

I don't shoot it alot although I really like it. I think Essex gets a bad name. Probably 7000 - 8000 rds. through it now.

It is my first homebuilt gun. Except for this one trait, it has been exceedingly accurate and reliable. It was quite dirty when this occurred - approx. 450 rds. of lead bullet loads since last cleaning. I wiped it down some before the photo so the details would be clear but otherwise didn't touch it.

If you had described this MF to me I think I would have said 'impossible'. To wit:

The empty is wedged into (under) the mag lips - hard. It will have to be pried loose. I'm assuming the extractor pulled it under there, but I'm not quite sure how.
The extractor is no longer engaged under the case rim.
The empty is NOT touching the slide that I can see.
The slide stop IS engaged.
The empty DID hit the slide quite hard, since it is ruined. So where did the energy come from to pull it back away from the slide? It's almost like there were 2 rearward impulses back on the slide. If so, where did the second one come from, and why did the slide stop engage only on the second try? There has to be a second rearward movement, since the case was ruined on the first and is now pulled away from the slide.

Also, I occasionally find an empty on the ground that has been jammed and ruined the same way. Strange.

Anyhow, I thought some of you fellow 1911 geeks might be interested.


http://i113.photobucket.com/albums/n240/gbw_jr01/IMG_0997.jpg

http://i113.photobucket.com/albums/n240/gbw_jr01/IMG_1000.jpg

The mag is a Checkmate 'hybrid' design. I've 20 of these mags and had a good bit of trouble with them - I think the springs are too weak, and the lip formation seems spotty - on some of the stainless versions, it's nearly impossible to insert the mag without a rd. jumping free. I've installed the '11 lb.' springs from Wolff, we'll see if that helps.

[RogersPrecision]

gbw,
I've seen this before.
I believe it is a combination of an improperly tuned extractor and too wide magazine feed lips.
The extractor should have some travel. As a case is pushed up into position, the extractor should flex outwards at least .020". And the bottom corner should have only a small radius. The object is to have proper tension whether the case is high or low on the breechface.
As for the magazines, well they are probably toast.

[rcmodel]

It's the extractor. And maybe the magazines too.

Here is a great explanation.
http://www.thehighroad.org/showpost.php?p=3763974&postcount=11

rc

[gbw]

Thanks, gentlemen. I'd suspected the extractor as well, it is almost certainly over 'gunsmithed' by me I'm afraid, when I first did the gun. It's probably a crouton along with the mag. Also this is one of the few 1911s I own that does not have the EGW oversized FPS. Usually I fit them tight with a very small radius on the bottom if any, courtesy of the ledgendary 1911Tuner.

I have to admit I still cannot understand the exact sequence of events that would lead to this condition. Just doesn't seem possible. I'm about to read Mr. RCs thread perhaps that'll help.


Well it did help a good bit. I still cannot see how the slidestop locked AFTER the case was driven forward into the slide then pulled back into the mag. away from the slide? But then no one ever promised me I'd understand everything.

[Shimitup]

I concur on the extractor issue, the case is falling away from the breech face and dropping into the mag lips as the slide come out of battery. As RogersPrecision says make sure the case is snug as it's pushed up under the extractor. Try filing a case rim a few thousandths smaller that you ever expect to encounter and make sure the extractor has enough travel to hold it as well. measure the rims on the ones that failed you may find them a wee bit small.

[gbw]

It passes the extractor tension test, always has. But some clocking could easily be an issue and the extractor is likely other ways 'gunsmithed' to scrap by the the original builder making "improvements". That would be me.

[RogersPrecision]

I don't think the case is being driven forward. I think the slide is driving it rearward into the lips, and continuing to slide lock.
The impact of slide to frame is jarring the crumpled case off of the barrel hood.

[gbw]

Sometimes the simplist thing is invisible to those who insist on being blind. Of course Mr. Rogers et al. is right and even after reading the right answer twice I didn't see it. There could not be 2 rearward impulses and there are none such. Thanks.

[Jim Watson]

There are also a lot of reports of guns that will not eject the last round, just leave the empty laying on top of the empty magazine. Same deal, the prior rounds have the top round in the magazine to guide them toward the ejector with minimum grip by the extractor. The last one doesn't. The angle is just not right to ram the last empty back into the magazine lips, but it is a similar fault.

[log man]

We pretty much all agree the extractor is most likely the problem. Think about this if the hook entry radius comes up a little too high and realizing the case is extracted from the linked down position and if the center line of the case rim should get below the point where the radius and the vertical wall meet the case would be pushed downward. OOPS! Clocking could also play in this.

LOG

[1911Tuner]

Impossible? Nay. Quite common, in fact. Always on the last round, and most often caused by a clocking extractor. Over-radiusing the lower edge of the wall is also a distinct possibility, though it doesn't cause it nearly as often as the extractor clocking...or rotating counter-clockwise in its bore as the round feeds. The really maddening part is that, sometimes the extractor rights itself and doesn't give a visual clue to the occurrence.

Load a full magazine, and fire the gun...and look closely at the extractor every time it feeds and goes to battery.

The mechanics:

The case gets stuffed part way back into the magazine...indicating good extractor tension...depresses the follower, preventing slidelock...and when the slide rides forward, it attempts to feed the empty case. The case noses up, and gets crushed between the slide and the barrel hood.

Why on the last round and no other time?

Rounds left in the magazine provide a convex surface that prevent the empty case from dropping below the top of the magazine feed lips...keeping it on a straighter path until it hits the ejector. On guns with standard, non-extended ejectors...once the slide moves far enough to uncover the magazine...the upcoming round bumps the case and aids ejection.

[RogersPrecision]

Tuner,
You missed the part about the pistol being at slide lock.

[1911Tuner]

Seen that happen a couple-three times, too...and that one's a little tough to figure out. It's still the ever-clocking extractor, though.

[Jim K]

RogersPrecision is correct. The recoil spring does not have enough power to dent the case that way and in that case the slide would be moving forward with the case, not smashing it against the slide.

What happens is that the case drops during the rearward slide movement, except that it doesn't actually drop from gravity. The gun is in recoil and the case, obeying good old Mr. Newton, tries to stay in the same place, allowing the gun to catch up with it and bring it in line with the magazine lips. The residual pressure in the case has enough power to drive it into the magazine lips, then the slide rams into the case mouth, denting it as shown.

I once concluded that the extractor is indeed playing a role, not because of how it grips the case, but because it doesn't. Either the extractor is defective or it has not fully engaged the rim (possibly due to "clocking"). Either way, the extractor is not holding the case, allowing it to escape and "drop".

The pistol is at slide lock because the case did not push the follower down far enough.

Jim

[1911Tuner]

The crunched case mouth comes from impacting the barrel hood. Study it and see that the two marks are about 30 degrees apart. If you match it up with right side corner of the barrel hood, it will fit like a piece in a puzzle.

I've also seen this happen on a few occasions due to either the extractor's fitting pad...the forward one just behind the claw...being too large to allow the extractor to contact the case rim. More rarely...and so far, only in the old Thompson Auto Ordnance pistols or early Essex slides...which had the extractor channel located too far to the right...which accomplished the same thing as the above description.

The mislocated channel is easy to spot. The flat edge of the extractor at the butt-end doesn't align wih the inside edge of the slide. This one can't be corrected with an oversized, fitted firing pin stop. About all you can do is to replace the slide.

The former can be corrected by reducing the fitting pad until the extractor case tensioning wall behind the claw so that it can contact the rim.

With both these conditions, there is almost always erratic ejection, and the last case is generally left lying loose on top of the magazine with the slide locked...and only occasionally does it get crushed on the return.

At any rate...whenever you see the case mouth crushed in this way...it's an extractor issue, assuming that the ejectorisn't completely missing.