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Thread: Magazine Timing (Looooonnnng)

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  1. #1
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    Magazine Timing (Looooonnnng)

    Since a couple have asked about it, I thought a little quick seminar on magazine release timing would be in order. Keep in mind that the magazine is not an accessory. It's a removeable, disposable part of a system in which each part works with another part...often as a redundant or backup...to the other. Browning was the master or redundant function. The magazine and all related areas of the feeding phase are the epitome' of that.

    As we know, the 1911 pistol was designed with controlled feed as a criteria. The cartridge should be fully and positively under control from the instant that the slide touches it until it's in the chamber. If at any point in the feeding phase, that control is lost, the liklihood of a malfunction is greatly increased. Not guaranteed...but increased. Reliability isn't about guarantees. It's about reducing the odds of a failure. Anything can malfunction. All we can do is strive to see that it doesn't...and we do that in large part by insuring that every round is under control until the empty case clears the port.

    I've often mentioned that the more recent wadcutter-type magazines release too early and too abruptly...but without really delving into exactly why that's a bad thing. The early, abrupt release point is fine for the short cartridge OAL
    that comes with correct seating depth of some styles of SWC bullets. Even though those rounds do misfeed occasionally, even in a well-tuned gun...because they were intended for target ranges...an occasional misfeed during a match isn't the problem that would be if the gun is the only thing between you and the morgue.

    Simply stated....the release point should come after extractor pickup is well established. Once that's been accomplished, it can release gradually or abruptly with no loss of control. Well-established being the key phrase here...it doesn't mean that the rim is barely under the corner of the extractor. it means that it's at least halfway there...with the rim under the claw, and the bullet ogive well into the chamber.

    Here is where the tapered/gradual release design comes into its own. By allowing the rear of the cartridge rise nearly parallel with the front, the approach to the chamber is straighter, with less angle to overcome while it breaks over to the horizontal plane. This serves to reduce the amount of stem binding that's present with the parallel/early/abrupt release wadcutter magazines...which don't allow the rear to rise. That forces the round to climb the feed ramp at a sharper angle.

    When the round approaches the release point at a steep angle, the rim is also at a steep angle relative to the extractor. If the extrator has a sharp corner on the bottom, it can contact the inside of the rim, and cause a failure to go to battery. Radiusing the corner helps, but it doesn't address the whole problem.

    When the round releases too early and too abruptly, all that keeps it from getting ahead of the extractor is the extractor itself. When the bottom corner has been radiused too heavily...the corner may miss the rim as it pops up...and we have the classic push-feed. If the claw snaps over the rim, the gun goes to battery. If it doesn't...it stops dead without the ability to extract the round with the "Tap-Rack-Bang" drill...and that malfunction is slow to clear in an emergency. Bad JuJu.

    Enter the extractor modification in which the bottom of the claw angles forward to aid in recapturing the rim should the slide knock it ahead of the optimum pickup point. It works well most of the time if correctly done...and enhances the odds that the extractor can catch up to a loose round and sort of "funnel" it back into the claw.

    The point is that all these modifications became necessary because of the desire to shoot short semi-wadcutter ammunition at targets. The short, abrupt release point...the extractor prep...and the ammunition all go hand-in-hand. How it came to be SOP for all guns and all extractors and all magazines is still a mystery to me.

    Only Colt stuck to the proper magazines for conventional ammunition. That is...cartridge OAL of 1.200 or more, with ball-like bullet ogives...and of course...7-round capacity with proper follower design. Given that Colt has been building the gun non-stop for almost a century, common sense and logic may should lead us to acknowledge that Colt probably knows a little more about the gun than many would suspect. I can promise that they know more about it than most of the aftermarket entrepeneurs who mount a campaign to convince us that we "need" this or that new/improved product. i.e. :If your pistol doesn't have THIS (pick one) then you NEED this pistol!"

    When the magazine release is correctly timed, it feeds the rim gradually and in a controlled fashion into the extractor pickup point...resisting the slide's impact and keeping the round in contact with the slide rather than being knocked forward of it. The bullet nose is in contact with the feed ramp, and is being cammed upward. The rim is also rising as it moves forward in the tapered lips...both being pushed upward by the magazine spring. This push is even and nearly parallel front to rear, unless the follower pitches forward, and effects a nose-dive into the ramp...causing the round to climb at a sharper angle.

    When the release point is correctly timed, it hands the round off, and when it finally gets free, the angled breechface takes over and continues to let the rim come up gradually...under resistance...to keep it in contact with the slide as the round makes the final bit of breakover into the chamber. The magazine and the breechface are redundant features that compliment and back one another up in the event that either is less than optimum. Of the two, the magazine is the more critical. You can find happiness with a vertical breechfacce and a late/gradual release magazine than with an early/abrupt release magazine. You can also find it with a correctly angled breechface and an early/abrupt magazine...but just not with the same bet-your-life reliability as when both are within spec. Here is where the intermittent malfunction comes from. The one that has no rhyme or apparent reason, and occurs so infrequently as to cause us to chalk it up to fluke or bad ammo...but there's a mechanical reason for it all the same...and it's usually the magazine.

    If the gun and the magazine are within spec...assuming a good extractor that's properly tensioned...the average man will seriously deplete his bank account in an attempt to buy enough factory ball ammo to cause a misfeed.

    I have a pair of ORM 1991A1 Colt 5-inch guns that are within spec in all critical areas. I've used nothing but 7-round magazines since day one...and mostly Metalform's "wadcutter" designs. The pair has over a quarter-million rounds collectively. They've been through one complete rebuild/refitting, and are both on their third barrel. 95% of the ammunition has been my reloads...and 95% of that has been with my home-cast and commercially produced cast lead...of all shapes and descriptions. One has never malfunctioned other than the one time that it failed to lock empty due to a broken slidestop lug. The other has had maybe a half-dozen...attributable to the ammo in all but one...and that one was due to a cracked magazine...in 15 years of hard use. Neither pistol has lost an extractor...ever. They've gone up to 75,000 rounds without even a need for retensioning the extractors until recently when I finally tossed a batch of brass which had rims so badly oversized that the extractors took a set on the diameter...and when I switched to a new lot of once-fired brass, the ejection was a little weak. No failures to eject...but just a little weak. I did retension at that point...almost a year ago...and have had zero failures to extract or eject.

    I have another beater that required a little tuning. A NRM Colt that had an MIM extractor. I relpaced it with a used USGI extractor that came out of a junker 1918 B;ack Army Colt. 30,000+ rounds without a failure. I attribute this awe-inspiring performance mostly to the magazines, and take just a little credit for the tweakin'...which was very little. No "Ramp and Throat" work...No mirror polishing...No voodoo or magic tricks. The feed ramps are
    far below what most smiths consider minimum...at .300-.320 deep.

    Magazines...Extractors...Ammo.

    Check-Mate industries has stepped forward and said that if we want'em, they'll supply'em...and without having to go through the middle man to get'em. These tapered hybrids that they make are the best of the best, and I strongly advise one and all to take advantage of it. If your gun won't run with these...you've got bigger problems than a magazine can cure.

  2. #2
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    Great write up...of course.

    From all the conversation on mags, it seems the hybrid is the best of the bunch...even with ball? If I read that and other posts correctly, why bother with the GI format which may need "timing" ?

    I assume when JMB designed the GI mag he had a good "handle" on the ammo specs that were going to be used. Given it was designed for one customer...the army. In todays world with all the "different" ammo available, for good or bad, I'd expect the rims to be different? Also, I don't think "reloading", where rims expand, was in JMB's mind for the GI mag.
    Is that a case for the hybrid instead of the GI mag? Or I am off base?

  3. #3
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    Quote Originally Posted by auto45
    From all the conversation on mags, it seems the hybrid is the best of the bunch...even with ball? If I read that and other posts correctly, why bother with the GI format which may need "timing" ?

    They're especially good with ball, or any other hollowpoint with a ball-shaped ogive.
    The GI hardball style may or may not need any tuning. My one example did...even though it fed...while the four that Deadmarsh got didn't need a thing. I'm persnickety and a little hard to please. I can feel it and hear it if a round doesn't feed just exactly the way I want it to. That's the beauty of the GI magazine. It's a cinch to tweak if it releases a little late.

  4. #4
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    Quote Originally Posted by 1911Tuner
    Check-Mate industries has stepped forward and said that if we want'em, they'll supply'em...and without having to go through the middle man to get'em. These tapered hybrids that they make are the best of the best, and I strongly advise one and all to take advantage of it. If your gun won't run with these...you've got bigger problems than a magazine can cure.
    DUUUUUUUUUUDE! When?























    I'm impatient!

  5. #5
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    Quote Originally Posted by Nitrox
    DUUUUUUUUUUDE! When? I'm impatient!
    Ahhhh...Patience, Grasshopper. Good things come to those who wait. Jackie says about 2 months.

  6. #6
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    Timing

    To expound a little further...As most of you who have been here longer than a week know...I'm a reliability freak. I don't care a whit what the gun looks like, or even if it's tack-driving accurate. I want it to work...Period...and that just about covers the extent of my effort on the 1911 pistol. In that light, I guess I'm a specialist of sorts...whatever that encompasses. I have done a little customizing...A little. I've done some accurizing...A little....but nothing even approaching world-class Bullseye accuracy tuning. Work like that, I leave to people like our own Jerry Keefer. I'm a reliability tuner, pure and simple. A mechanic. I'm like the guy at the local auto-repair shop. The big boys build the cars for the Nascar racers...while the guy on the corner gets your daily commute vehicle runnin' like a top. He gets little glory for his efforts, but he is what he is...A mechanic.

    In the pursuit of the 100% reliable 1911 pistol, I've picked up a few things along the way. Most of it applies to the oddball guns that are out-of-spec, or the ones that seem to malfunction once in a while...or even a few times in rapid succession...and fall back into flawless function for another 500 rounds.
    These are the truly maddening examples that require little tricks of the trade, plus very often a measure of luck in order to set'em right.

    As I've often said...to the point of wearing it out...The biggest majority of functional issues with the 1911 pistol are simple in cause, and almost always pretty simple to correct. It can usually be narrowed down to the magazine...the extractor...or the ammunition...or related areas of the gun.
    For instance, a too-narrow breechface guide rail dimension often mimics excessive extractor tension, and bad barrel ramp geometry mimics bad frame ramp specs, with a 3-Point Jam as a result. This is probably the single biggest reason that I jump up and down whenever I see the advice to "Polish the Feed Ramp" as the first approach to correcting a feeding problem...when it's at least 90% likely that the magazine is at the root of it.

    So...In the course of going on 43 years in my pursuit of Nirvhana...A careful study of magazine function has been a productive one. I've "fixed" more pistols by doing no more than using a good magazine than I have with actual tweaking and modification of the guns. Probably at a rate of 10:1 or close to it.

    Many people who are otherwise skilled and knowledgeable with the 1911 pistol fail to understand how the gun actually functions...or how it's supposed to function when all is right. An even smaller percentage understand how the magazine should function. They'll look at a well-made magazine...notice that the feed lips are well-formed...and assume that it's a good design. While these magazines are actually very good, and will function in a large percentage of the guns that they're likely to find a home in...it ain't necessarily gonna happen. These are specialty magazines designed for specialty ammunition, and when used with the ammunition they were designed to work with...they do very well. They are not, however...a "Jack of all Trades" by any stretch. That many do fill that role much of the time is no indication that they're the best design for all ammunition and in all situations.

    We need only watch the difference in the feed as the slide strips the round to see the difference in the angle of approach to the chamber. With the "wadcutter" magazine, it dips into the feed ramp and turns back upward...strikes the top of the chamber, and angles back toward the horizontal plane...finally entering the chamber. While this is happening, the poor rim is trying to find its way under the extractor at such an acute angle, that it's a wonder it finds it at all.

    With the proper magazine meant for use with Other-Than-Target ammo...the
    round strikes the feed ramp at a much shallower angle and begins to come straight up with front and rear nearly parallel as the tapered lips let the rim rise at the same rate of ascent...or nearly so. By the time the extractor starts to pick up the rim, the cartridge is entering the chamber on a nearly horizontal plane. Absent is the feeling of something hitting the gun, and is replaced by the smooth feeling of a well-oiled machine that is applying a slight braking effect for the last bit of travel into battery. This is as it should be. If the round chambers too resistance-free...the slidestop pin and the lower lug feet take a pounding. Not as great as by dropping the slide on an empty chamber...but more than is conducive to long barrel lug life.

    Of course, there's a balance between enough resistance and too much...but that window of opportunity is fairly wide, and as long as the gun is reasonable clean and the recoil spring is in good shape...RTB reliability is as it should be. Besides which...a pistol that feeds with a "Ka-Chunk" is applying more brake than one that feeds smoothly and slows the slide just as it goes to battery.

    Study the magazine. That's where a big part of reliability is found.

    More later. Dogs gotta be shuffled in, fed, and put to bed.

  7. #7
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    Quote Originally Posted by 1911Tuner
    Ahhhh...Patience, Grasshopper. Good things come to those who wait. Jackie says about 2 months.
    Is that 2 months until the group buy can begin or two months delivery time after the order is placed?? When will pricing be determined?

  8. #8
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    Quote Originally Posted by aphco
    Is that 2 months until the group buy can begin or two months delivery time after the order is placed?? When will pricing be determined?
    Dunno and dunno. We'll have to ask her. She's registered by the username
    "Check-Mate"

  9. #9
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    Quote Originally Posted by 1911Tuner
    Dunno and dunno. We'll have to ask her. She's registered by the username
    "Check-Mate"
    Done. Waiting for her answer.

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