Odd failure to feed

[CherryRiver]

This past weekend I had the pleasure of participating in the Michiana Territorial USPSA match at the wonderful Bend of the River Conservation Club in Niles, Michigan.
As usual, I had my trusty Colt Special Combat Government Model in the holster, operating in Limited-10 division. Only, this time it wasn't so trusty. After the second or third (of the seven- it was a 225-round match) stage, I had at least one stick-up failure to feed on every run. On the last one, I found out later watching the video a friend shot of my run, I had three!
That's a year's worth for this gun. But what was striking was that every one of the tie ups came at the second shot of the reload. Now, in USPSA, you're always reloading on the move and rarely empty a magazine. Instead, you make sure you never see slide lock by dropping your mag before you run dry.
That means that for every one of the sticks, the first round out of the magazine failed to strip off and get up in the chamber.
During the heat of the game, I didn't really notice, but every time it failed, the previous empty had ejected fine (the one left in the chamber from the previous load-up), but with no round in the chamber, all I got was a click.
I didn't bother to tap the mag bottom, since I knew I had pounded the long ten-rounders in there properly. A quick rack on the slide and I was back in business.
Since it happened twice on one stage and three times on another, that means it wasn't just all the same magazine.
For reference, I use four Wilsons and one McCormick. I see from the pictures it happened to both kinds. All were a bit dirty, but not terrible, and had been cleaned within memory, if not the preceding week.
There's only one thing else I can think of- I had recently changed out the original recoil spring for a standard power progressive-wound one from Brownell's. I'm not sure how that would affect only the top round in a full mag, but there it is.
Suggestions?
Thanks
Bill

[Canuck-IL]

I had at least one stick-up failure to feed on every run

with no round in the chamber, all I got was a click.

I'm missing something in the description...was there a live round jammed or are you saying the slide closed to battery w/o chambering a round?

/Bryan

[1911Tuner]

Hmmmm

Sounds like a rideover failure to feed. Odd one, because rideovers generally tie the gun up pretty solidly with the slide out of battery...and it normally happen on or near the last round...but I suppose anything's possible.

Mag spring not strong enough to get the round up in time. Lightly loaded ammo or oversprung slide causing short-cycling. The slide isn't runnin' back far enough to strip the round.

Too-heavy radius or bevel on the bottom edge of the center rail, camming over the round...also not highly likely without tyin' up the gun. May strip and feed the round when hand-cycling, but may not at full speed if any of the other above factors are in play.

'Bout all I can think of when I'm in a rush...

[John]

From his description, it looks as if he had a plain old FTRB. He says that he reloads while still the chamber is loaded, so there is a live round there. That round ejects fine but the first round of the new mag fails to chamber completely.

I am not sure what it means by :

There's only one thing else I can think of- I had recently changed out the original recoil spring for a standard power progressive-wound one from Brownell's. I'm not sure how that would affect only the top round in a full mag, but there it is.

If that's a progressive 16 lbs spring, then maybe the spring doesn't have enough mph to push the new round in the chamber? Being progressive, I believe it is softer when reaching its full length.

Of course, it would be nice if he had stopped once to see how the round was in the gun when the malfunction occured. We need to know where the nose of the round was and where the rim of the round was when the stoppage happened.

[1911Tuner]

John...You been in Lena's cookin' wine again? :D

Prob'ly in a rush too, and didn't see this part:

During the heat of the game, I didn't really notice, but every time it failed, the previous empty had ejected fine (the one left in the chamber from the previous load-up), but with no round in the chamber, all I got was a click.

At first, I thought that "Stick-up" meant a live-round stovepipe, and almost responded to that...but that wasn't it.

[John]

Ah, I missed that Oh Master!

Humble apologies, but you know that if I do not have my first glass of Nescafe, the system is dead. I keep telling myself to stay away from the keyboard in that condition, but my wish to help people out makes me sit down and answer questions. Some times, with strange results, as above!

[1911Tuner]

Humble apologies, but you know that if I do not have my first glass of Nescafe, the system is dead.

Hey...That "Stick-Up" thing almost threw me, too. Thought it was a failure to go to battery. I had to read back over it a couple times before I got the picture.

[CherryRiver]

Man, I gotta reduce the mellifluousness of the language.
Sorry. A stick is what I tend to call any operational failure of any semi-auto. Probably not a good choice. But, sometimes my tendencies as a storyteller get ahead of my capabilities for precise language.
Yep, it failed about eight times with different magazines to strip off the first round only of a full magazine, leaving a closed gun with an empty chamber, resulting in a very loud click.
Since it was a big match, slowing down to look wasn't possible. I didn't even realize until later, when I saw the videos, that I had an empty chamber every time, and that the failures only took place on the second attempt at a shot after a reload.
I think I can get some time Saturday to change the spring and run a hundred through it, but I'm busy setting up my own 3-gun for Sunday, in which I'm shooting a Webley and a Lee-Enfield anyway.
They don't stick, they jam.
Bill

[1911Tuner]

Bill...A little more info may help diagnose it.

Recoil spring rate, if too heavy, may be a player, though not likely that it would cause the slide to ride completely over the round and go to battery.

Is there a lot of up/down play in the slide? Is there an excessive amount of clearance between the bottom of the center rail and the top of the frame? You'll need to disassemble the frame and use a feeler gauge to determine it. I like to see about .007-.010 inch between'em.

Check the bottom front corner of the center rail to see that it's getting a good purchase on the case rim. Some people will see that bevel or radius and figure that if a little is good, a lot would be gooder...and work on it in the mistaken belief that it'll smooth out the feeding...but it can cause the rail to ride over the rim and actually cam the round back down into the magazine. I've seen this one more than a few times. Sometimes it's repairable...sometimes not...depending on how far the "smoothing" was taken.

Remove the recoil system, and hand-feed a few rounds so that you can see how much purchase the rail is getting on the case rim. If the rail corner looks good...it may be the position of the magazine in the well, but the effect is the same.

[CherryRiver]

The reason I mention the recoil spring is because it's the only thing I can think of that has changed, apart from varying degrees of dirtyness that would be expected from use.
The SCG is a custom shop gun and mine is pretty darn tight. One thing I know, not pertinent to this, is that the chamber is the tightest .45ACP chamber I have and so I use this barrel as a gauge for checking match ammunition.
The slide fit is quite tight but not at all sticky.
I traded into the gun a year ago and it had what I would guess 3000-6000 rounds of use. It has run fine, with the exception of being intolerant of bad ammunition, specifically plated bullets that got shaved during seating because my Dillon wasn't belling the cases enough at the powder station.
Apart from that, it has run very well indeed.
This malfunction came on pretty suddenly. The gun gets cleaned every match, but the extractor tunnel was a bit on the dirty side. Not impacted solid, but the swab pushed through came out black and gooey.
I use FP-10 so it wasn't unlubed. I do use a touch of Tetra grease on the frame rails and slide stop pin.
The ammunition is Rainer 230gr round noses in front of 4.6gr of WST, loaded on a Dillon SDB with the separate crimp die. My inexpensive chrono thinks it produces about 750-760fps on a moderate day. I clean my empties to an excess and my ammunition is "too shiny" according to one friend. It has been 100% reliable in my old Combat Commander and new 1991, with the exception of the shaving problem since corrected.
The spring in question is a Wolff variable-power 16 1/2 pounder. The OEM spring was okay, but I wanted to change it in advance. No special reason for the progressive choice except that I thought it sounded like a good idea.
Again, the magazines were a bit dirty (they get used for about three matches a month) but not terrible. One thing I did to upset the diagnostic applecart was that I cleaned them, too, and gave the springs a little bit of stretch on the way back in, just a little. I do like to press down on followers to keep track of upward pressure and they seemed maybe a touch weak.
The Wilson 10s have been excellent for me. I note that replacement springs are not available from Brownell's for them and so I guess I have to call Wilson.
Anyway, back to the diagnosis: the slide rail is getting a huge grab on the top rim; hand-cycling the springless slide gives a loudish clack as the top round in a full magazine snaps up, too. I don't have good dummy ammunition here and I am not crazy about cycling live ammunition in the house, so it's going to have to wait until the weekend.
But failing to feed up only the first of the ten rounds is just so weird. I could get it if it was the last (not that a USPSA gun ever goes to the last round).
Range time is next, and I appreciate the response.
Bill

[1911Tuner]

Bill...I'm gonna call this one short-cycle. The slide isn't moving back far enough to uncover the next round...and it simply rides across it and back into battery. Either go back to the old spring or up the power level of your ammo.

[CherryRiver]

I have it!
Short-cycling it is. What was catching me up short was the first-round-only thing. But as I apply the analytical computer to it (as soon as I rubbed the two sticks together long enough to get some smoke), I realize this- that the barely marginal spring power/ammunition power/dirtyness balance was right at the edge, except that with the full mag, the top round is pressing up against the slide rail the hardest , and creating just enough drag to unbalance everything.
Take out a round and the drag is lessened just enough to let things go on normally.
One other takeaway from this: I thought the gun was shooting very fast with very soft recoil, given a load that makes major on the power factor. The videos also suggested that, too, since it looked like my "splits" were unusually fast for a mid-level competitor (on my good days) like me.
WST has a deserved reputation for being soft-shooting while still being snappy-burning enough (like the original Bullseye) to reliably cycle. I've actually done some range testing with same-magazine comparisons with four other powders and have some empirical proof in hand (pun intended).
Apparently I stumbled onto the exact point in the graph where all the lines intersect.
Since increasing one's power factor in USPSA (all I use this gun for) is a serious fox pass and I couldn't bear the embarrassment of going over 170, it's back to the OEM spring.
Interesting.
Bill

[saltydog]

Tuner,

Twice you made mention of 'the center rail'. I don't understand exactly what the center rail is.

Maybe the notion of 'lowering the rails' on the frame prevents me from understanding what you ment when you mentioned the center rail.

Enlighten me Kemo-Sabe.

Thanks,

salty.

[1911Tuner]

I realize this- that the barely marginal spring power/ammunition power/dirtyness balance was right at the edge, except that with the full mag, the top round is pressing up against the slide rail the hardest , and creating just enough drag to unbalance everything.

Yes, Grasshopper. Whenever balance is restored, harmony follows. The Ying and the Yang. The flow of the Chi must be smooth.


Twice you made mention of 'the center rail'. I don't understand exactly what the center rail is.

The disconnector rail, Salty. It serves three functions. Cocking...Operating the disconnector...and stripping the round from the magazine.

[CherryRiver]

The shame of it is, I never even got a chance to get the Dremel out of the drawer...
Bill

[1911Tuner]

The shame of it is, I never even got a chance to get the Dremel out of the drawer...
Bill

AAARRRRGH!!!

[CherryRiver]

Kinda loud in here, isn't it? Better put those plugs back before runnin' the belt sander.

[twin oaks]

Bill, forget the belt sander- I've got a nice Porter-Cable 3/4 inch drill and some cylinder hones you can use on your feed ramp. It'll make it nice and shiny.:)