1911 feeding question

[il.bill]

1911Tuner

Thank you for the photo. That picture is easily worth a thousand words. I would like to save that on my computer for reference, if you do not mind.

I purchased five 7-round NOS 'Colt' magazines from Robertson's Trading Post for $75 delivered a while back. They say 'Colt 45' on the base plate, but there is no Prancing Pony nor follower dimple anywhere to be seen. Two or three do not lock the slide back when empty, but they feed reliably so far.

Thank you again for sharing your knowledge so often for the benefit of so many of us. Keep up the good work!

 

[1911Tuner]

They say 'Colt 45' on the base plate, but there is no Prancing Pony nor follower dimple anywhere to be seen.

Those are counterfeits. The manufacturers get around the infringement question by not using the horse logo, and lead uninformed buyers to believe that...because it says COLT.45 or COLT 45 Auto...that it's a Colt magazine.

I used to see these a lot at gun shows selling for as little as 5 bucks a copy. Many of them were actually pretty decent magazines after changing the springs. I had one that lasted for years before the baseplate welds finally failed. Others that were outwardly identical weren't worth bringing home.

Incidentally, Colt hasn't made magazines in house in over 50 years. They contract for them made to their specs...usually Metalform, Check Mate, and OKAY Industries...but recently, they've bought them from others.

 

[ATLDave]

So given 1911Tuner's responses, I'd like to know if you typically experience this issue with the last round or second to last round. You mentioned that the problem occurs with more than one magazine but don't mention when the problem occurs.

I haven't noticed a pattern to it yet, but I'll start paying attention and report back if it manifests again.

 

[ATLDave]

Might be nice to know what brand 1911 we're talking about

Kimber. No brass pictures at the moment, but is there something you're looking for?

 

[Skylerbone]

An flat indentation on the base of spent brass caused by machining errors in the area above the ejector. My S&W after initial clean up (later scraped smooth by a smith).

The AOs were cut with an angle rather than a radius at the J Cut (port side when in hand) but neither of these errors would be common with a Kimber. That makes magazines/springs the primary suspect, with a more remote chance of breech angle running a very remote second. Still something to look for.

 

[Powderpacker]

I have had this problem at times. My magazine springs have never been replaced. 1911Tuner, whose springs do you recommend?

I have a series 80 Gold Cup. I shoot 200 grain LSWC's over 5 grains of W231. I think the Gold Cup uses a 16# spring. Would I be better off with a 14# spring?

Jimmy

 

[1911Tuner]

My magazine springs have never been replaced. 1911Tuner, whose springs do you recommend?

Wolff, but be sure to order the right spring. If you're not having any problems related to the spring, there's really no need to replace them, other than as a preventive measure.

Recoil spring: As long as the slide makes full travel rearward and goes to battery reliably, either one will do.

 

[gym]

It's nice to see true "genius" explain things we take for granted. It's amazing how something that looks so simple, could be that complicated. Great job explaining the nuances of the extraction issue.

 

[1911Tuner]

I have a recurring, sometimes maddening habit of asking "What is it for?" It's made me unpopular in certain circles and in certain situations, because there is just as often no practical answer to the question.

We can often determine the answer to that question by studying and thinking...by asking of the designer as if he were standing there: "Why did you do that?" What is its purpose?" "What is it FOR?"

In the case of that little dimple, I asked that question several years ago, and...being unable to sort it out or get Johnny Browning to answer me...I decided to embark on an experiment with a pistol that had long since proven its dead-nuts reliability.

I removed it from the followers of a half-dozen magazines and started shooting. Almost immediately, I started observing two intermittent problems had hadn't been present with the dimples in place.

The first, and most frequent, was the slide locking open with the last round loose on top of the magazine lips. The other, less frequent, but still repeated often enough to draw a conclusion...was the round chambered ahead of the extractor, stopping the slide out of battery...but there was a variation that wasn't readily apparent and one that I noticed quite by happenstance.

Whilst preparing the fired brass for reloading, I noticed a sharp burr kicked up on the edge of a few case rims, along with a telltale mark further inboard that matched the shape of the extractor nose. A mark and a burr that I'd never noticed before...leading me to coin one of my favorite and oft-repeated axioms...

"Just because it's functioning is not proof that it's functioning properly."

Curious, I pressed on.

I started single-loading the pistol by locking the slide to the rear...chambering a round by hand...and dropping the slide, forcing the extractor claw to snap over the rim. Of course, the burr and mark were reproduced on every case.

Before long, I noticed a loss of extractor tension. Forging ahead after resetting it...it happened again. Shortly after the 4th retensioning cycle...the extractor hook snapped off flush with the breechface.

You may draw your own conclusions.

 

[Krogen]

1911Tuner: I'd sure like to see you write a book! I'll place my order right now, pre-publication!

As to "what is it for?" we have a practice at work called Five Whys. You can see where it might lead. Simply keep asking why for every answer to the previous why. Of course, it doesn't have to stop at five, but must not be fewer than five whys. This can get comical, intense, annoying etc. but it makes people think; and some folks angry. I believe I'll add "what's it for" to my repertoire!

 

[tipoc]

A good thread and good posts.

tipoc

 

[RainDodger]

Yes - this is all excellent info for 1911 magazines!

I have a number of 8 round Sig mags. ONE of them (the others appear fine) tends to lock my slide back prematurely and the round in the mag is partially pushed forward but not free of the mag's feed lips yet. It's still captive, but the slide locked back.

Is that sounding like a weak magazine spring? The dimples are present in the follower and the other Sig mags work okay. I'm running these in a Springfield TRP with an 18 lb. Wilson recoil spring. Thoughts about it?

Thanks a lot.

 

[MCMXI]

... original "Hardball" type with full tapered feed lips and late, gradual release. ... "Wadcutter" type, with parallel lips and early/abrupt timed release ... "Hybrid" which combines the feed/release characteristics of the other two.

I removed it [little dimple] from the followers of a half-dozen magazines and started shooting. Almost immediately, I started observing two intermittent problems had hadn't been present with the dimples in place.

You may draw your own conclusions.

The obvious question here is did you test each of the magazine feed lip styles described above? Did you observe the same failure with all three feed lip types?

 

[1911Tuner]

The obvious question here is did you test each of the magazine feed lip styles described above? Did you observe the same failure with all three feed lip types?

At the time, all I had was WW2 era USGI magazines, so no.

I've noticed the same failures in several modern "wadcutter" type magazines with smooth followers.

And I'm havin' a little trouble wrappin' my head around why different styles has anything to do with it. The problems were never noted with the stock followers, and immediately appeared when the dimple was removed with a file, and then went away again when the followers were replaced.

That pretty much only leaves room for one conclusion.

 

[wally]

I've no doubt the dimple on the follower is important for the last round. But I'm having a very hard time seeing how it can have any effect if the push feed is happening with three or more rounds left in the magazine.

I was having some ignition problems with Tula primers in a 9mm 1911 and went to a 26 lb hammer spring. Made the pistol push feed city! Went back to the stock spring and things seem back to normal. Same as too strong a recoil spring the recoil foce doesn't decouple from the frame and basically leaves the round sitting there with the magazine and gun moving out from under it. With a loose enough grip I could watch it eject the top round and feed the one underneath.

 

[1911Tuner]

I've no doubt the dimple on the follower is important for the last round. But I'm having a very hard time seeing how it can have any effect if the push feed is happening with three or more rounds left in the magazine.

That part of the discussion just sorta evolved from the original question...and you pretty much figured it out with the inertial effect causing the round to jump the magazine. Although it's usually a weak mag spring at the root of that, too much recoil spring can make it more likely to happen.

 

[Steve in Allentown]

I was having some ignition problems with Tula primers in a 9mm 1911 and went to a 26 lb hammer spring. Made the pistol push feed city!

I wonder if a lighter recoil spring in combination with the 26lb hammer spring would have worked.

The heavier the hammer spring, the more resistance the slide will encounter on its rearward travel. This should have the effect of slowing down the slide. I can't figure out how this would negatively affect the feeding of the next round.

 

[wally]

I wonder if a lighter recoil spring in combination with the 26lb hammer spring would have worked.

I switched in the lightest recoil spring I had when I switched in the hammer spring, how low you can go on the recoil spring is pretty much set by the force it takes to strip the rounds off the magazine.

The 9mm 1911 is much more prone to push feeds than the .45 because the rounds are significantly shorter and all the manufactures seem to put the spacers to compensate at the rear of the magazine which reduces the amount of feed lip available to hold the rounds. I use Checkmate and Metalform mags with Wolf extra power mag springs. I wasn't expecting push feed problems with the stronger hammer spring, but I wasn't totally surprised by it either.

 

[Steve in Allentown]

. . . how low you can go on the recoil spring is pretty much set by the force it takes to strip the rounds off the magazine.

Quite right. I just can't figure out the physics behind the phenomenon of a heavier hammer spring exacerbating an inertia feed condition.

The slide is having to overcome the increased resistance of the heavier hammer spring. This should have the effect of robbing momentum from the slide movement. Less momentum, less tendency for the round to end up forward of its starting position in the magazine, right?

Where's Einstein when you need him?

 

[1911Tuner]

I just can't figure out the physics behind the phenomenon of a heavier hammer spring exacerbating an inertia feed condition.

If you ever watch a very slow-motion video of a locked breech pistol firing, you'll notice that there's very little movement of the gun until the slide impacts the frame...and then it torques upward and backward violently. By robbing the slide of speed and momentum, it doesn't impact the frame with as much gusto.

Installing a heavy recoil spring has that effect, but you reach a point of diminishing returns pretty quickly, and the frame begins to be shoved backward rather sharply by the power of the recoil spring alone. Remember that, once the slide starts to move, a separate action/reaction system comes into play, with the spring providing the force vector between slide and frame.

By using enough mainspring...or maybe going a pound or two heavier...the slide's acceleration is resisted the instant the gun fires...before it gains much speed and momentum.

This effect is compounded with the use of a small radius on the bottom of the firing pin stop...as per Browning's original design...by reducing the mechanical advantage of the slide in accelerating the hammer's mass and compressing the mainspring.

The original firing pin stop radius was .078 inch...or 5/64ths. I've gone as small as .050 inch without ill effects...and it does tame muzzle flip to a noticeable degree.

 

[Steve in Allentown]

. . .that there's very little movement of the gun until the slide impacts the frame

. . . the frame begins to be shoved backward rather sharply by the power of the recoil spring alone.

By using enough mainspring...or maybe going a pound or two heavier...the slide's acceleration is resisted the instant the gun fires...before it gains much speed and momentum.

This effect is compounded with the use of a small radius on the bottom of the firing pin stop

Tuner, I follow your posts with great interest and have bookmarked many of them on multiple forums across the web. I understand everything you've written here and have incorporated these concepts in my tinkering.

But, I don't understand how, in this particular case, a heavier hammer spring (main spring) increases the possibility of an intertia feed.

 

[gym]

On a simpler note, which readily available magazines are best for the majority of 1911's. Preferably something that is easy to get hands on, like a Wilson or McCormick?
And is there a disadvantage to using the 8 rouders in guns that come with 7 rounders, "I can't possibly see one, but why not ask"

 

[wally]

And is there a disadvantage to using the 8 rouders in guns that come with 7 rounders, "I can't possibly see one, but why not ask"

My experience is that a properly setup 1911 will run fine with simple GI style magazines and wadcutter vs. tapered feed lips makes no real difference. Needing "fancy, expensive, special" mags is putting on a band-aid to cover up the real underlying problem IMHO.

The downside of the 8-round mags is they are prone to push feed the last round since they lack the dimple on the follower, which can be hard on the extractor eventually and they will sometimes give a feed failure on the last round. I carry the 8-round (7-round for Officers sized) in my pistol figuring if I don't get the 9th shot I was no worse off than if I'd had used a 7(or 6)-round mag.

I've always used the CMC "shooting star" or Mec-Gar for the eight rounders (although I prefer the CMC for carry because of the flush fit) and "GI forgery", CMC, Metalform or Checkmate for the 7-rounders -- doesn't much matter when the gun is setup right, as long as the mag spring is good and the follower has the dimple in the right place.

On alloy frame guns the point on the "devel", aka shooting star" 8-round follower can booger up the frame around the bottom of the feed ramp. When the last round chambers the follower gets dragged forward and the point hits the frame, its worse if the slide fails to lock back on the last shot. Its basically only cosmetic damage, but can be prevented by rounding off the point of the follower which is what I've always done to the CMC 8-rounders.

The original firing pin stop radius was .078 inch...or 5/64ths. I've gone as small as .050 inch without ill effects...and it does tame muzzle flip to a noticeable degree.

Small radius firing pin stop is pretty essential with a 10mm 1911 firing full power loads.

 

[1911Tuner]

But, I don't understand how, in this particular case, a heavier hammer spring (main spring) increases the possibility of an intertia feed.

It doesn't. It decreases the chances. I must've misread your question.

 

[wally]

Quote:
But, I don't understand how, in this particular case, a heavier hammer spring (main spring) increases the possibility of an intertia feed.
It doesn't. It decreases the chances. I must've misread your question.

I've not mis read my actual experience with a 9mm 1911. 26lb hammer spring made it push feed city. Replacing the stock hammer spring and no push feeds in 400 rounds since the return to normal -- I don't run enough recoil spring to snap the extractor over the rim, so every push feed is a stoppage.