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1st round from mag always low, 4+1 syndrome

Discussion in 'Handguns: Autoloaders' started by js2013, May 24, 2015.

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  1. js2013

    js2013 Member

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    Anyone know the cause of the 4+1 syndrome? Ayoob refers to it but I've never seen the reason explained. I figure it has to do with lockup but would like to know the details/theory/resolution.
     
  2. ATLDave

    ATLDave Member

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    I'm not familiar with this "syndrome." Can you describe it?
     
  3. ApacheCoTodd

    ApacheCoTodd Member

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    First round double action?

    Not enough info to effectively speculate.

    Todd.
     
  4. CNobbe

    CNobbe Member

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    The theory is the first round chambered might impact a little differently than the next four and so on. Not the first round from the magazine. Whether it's barrel lockup, barrel temp changing, or something else is pretty hard to diagnose.

    The guns I shoot the most consistent tight groups with don't seem to have any issue with the first round from the mag and accuract. (P99, CZ 75, 1911(s).
     
  5. 9mmepiphany

    9mmepiphany Moderator

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    The prevailing theory, the last time I did any reading on it, had to do with how the first round was being chambered and how releasing the slide from slidelock had a different dynamic of forces, on barrel lockup, than when the slide was driven to the rear of it's travel by the recoil of the preceding shot.

    The effect will lessen or increase based on the consistency of the lockup of the action.

    In my youth, I played with it a bit and my experience was that it occurred less often with dropping block actions (P-38, Berreta 92) than tilt barrel actions (1911, SIG, CZ). It was completely absent in my H&K P9S and P7...but I don't know if it was the H&K quality of build or the action design. Interestingly, it doesn't seem to occur in single shot pistols...or Olympic pistols, which use blowback actions
     
  6. The Lone Haranguer

    The Lone Haranguer Member

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    "4+1 syndrome" is like this: With five-round groups fired from a bench or machine rest, the first round, which is hand-chambered, impacts apart from the next four, which are chambered at the full speed of the action and more clustered together. It has something to do with slightly different lockup and alignment of parts, and should go away as the pistol gets more rounds through it. Mostly, it gives gun scribblers something to fill up space with. :p

    This makes sense because dropping block actions don't tilt the barrel.

    I don't know about the P9S, but the other guns have fixed barrels.
     
    Last edited: May 24, 2015
  7. kcofohio
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    kcofohio Contributing Member

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    Now that's funny! :)
     
  8. Walt Sherrill

    Walt Sherrill Member

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    Maybe, maybe not. (While folks can speculate with almost no information, that doesn't mean their speculation/analysis is correct or addresses all of the important variables...)

    It would be much better if we knew more about the gun in question -- they type of barrel lockup, whether it was DA/SA (with different trigger pulls between the first and following rounds), DAO, striker-fired, etc.

    I've never noticed MUCH of a difference between 1 and 2 rounds on guns that had the hammer or striker fully or partially cocked by slide action with the first shot; that makes me think that some folks might be causing the difference when they squeeze off that first shot.

    I've also not heard a lot of discussion of this phenomenon being seen when using a Ransom Rest. Anybody know whether it raises its ugly head in that sort of testing?
     
    Last edited: May 24, 2015
  9. 9mmepiphany

    9mmepiphany Moderator

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    The H&K P9S operated on the Delayed Roller-locked System.

    While the barrel wasn't fixed...it came off the frame when the slide was removed...it didn't reciprocate either
     
  10. The Lone Haranguer

    The Lone Haranguer Member

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    Unless you were referring to loading the first round into the chamber from the magazine, the first round from the mag is the second shot from the gun.
     
  11. ATLDave

    ATLDave Member

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    I'm highly skeptical. Someone would need to provide some pretty compelling evidence for me not to suspect human error as the cause.
     
  12. 9mmepiphany

    9mmepiphany Moderator

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    Back when gunzines were the only source of gun information, this was pretty common knowledge.

    I noticed it with my own guns and thought it was just me. It even happened when shooting off a solid padded bench position. It actually made me feel better when I started reading that it was very common (among well respected handgun testers), testing new pistols.

    It does seem to go away with use, so I always figured it was part of the "break in" process as the various parts "mated" their contact surfaces with each outer.

    I've noticed that as accuracy expectations have gone down, that it seems less of a concern...likely because the shooters aren't accurate enough to noticed.

    Bear in mind that 25 yards used to be a common testing distance, whereas 10-15 yards now seems to be commonly acceptable
     
  13. js2013

    js2013 Member

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    "It does seem to go away with use, so I always figured it was part of the "break in" process as the various parts "mated" their contact surfaces with each outer."

    Everything I've read so far confirms what you said. It does it 100% of the time, and if I hand cycle the 1st round is low, but if I drop the slide it'll still be low but not as bad, which confirms the theory. It'll be intestering to see how long it takes to "break in". Visual inspection didn't show anything obvious but I'll take another look under magnification.
     
  14. Walt Sherrill

    Walt Sherrill Member

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    I'm still interested in seeing of the phenomenon is as obvious in a Ransom Rest test as in a hand-held test...

    ------------
    After writing the comment above, I went to the 1911Forum where I found a lengthy discussion of Ransom Rest results with some top-grade guns.

    Some of them had flyers (but it wasn't clear if it was always the first shot, and a few of them didn't!! Several of them had very tight 5-shot groups... (Note: you have to scroll down a good way in the article to see the results.)

    http://forums.1911forum.com/showthread.php?t=321236
     
    Last edited: May 26, 2015
  15. wally

    wally Member

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    Fouling shot?

    Isn't the first round out of a clean barrel always a bit off from the remainder?
     
  16. 351 WINCHESTER

    351 WINCHESTER Member

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    I used to own a Colt officers model .45acp. The first shot always went way left. I let others shoot it and it did the same for them. I read an article once that called this the "automatic syndrome". I sold the gun.
     
  17. Walt Sherrill

    Walt Sherrill Member

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    The first shot for a five-shot session isn't always shot through a clean barrel. And the phenomenon seems to occur whether the barrel is clean or not.

    Some believe the difference is how that first shot is chambered (either manually, are as the follow-up shot.)

    In the Ransom Rest tests I posted a link to, earlier, that variable wasn't addressed, but it seemed as though most of them started with a round chambered (manually) and the hammer cocked -- but no indication whether the barrel was clean, or whether the first "test" round was chambered by a prior shot.
     
  18. Jolly Rogers

    Jolly Rogers Member

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  19. Walt Sherrill

    Walt Sherrill Member

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    Sadly, I only vaguely understand what's being discussed as I'm not as familiar with 1911s as other guns.

    I appreciate that the discussion is specific to 1911s and wonder whether the same phenomenon (and supposed cause/cure) applies to other weapons, as well?
     
  20. GLOOB

    GLOOB Member

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    Count me as a believer. Glock 17L, rental. I sorta doubt it was new, but I can't say for sure. I tried using the slide release vs sling-shotting, and it didn't make any difference for this gun. First shot was probably 15-20 MOA left. It was easy to see, because all the other shots went through a single ragged hole at what I recall was probably 15 or 20 feet. The first shot always refused to join the party, and it was always 3/4" dead left. 30-odd handguns fired, and this was the only time I have experienced it. Not to say that I can shoot all handguns accurately enough to have easily noticed something like this; with the G17L, I noticed on my first mag, was satisfied something fishy on the second, confirmed on all subsequent mags. After the second mag, I shot off the rest of my ammo loading only 5 rounds and shooting for accuracy, just to re-experience this. It's such an odd thing to see. I should also note, I was a better shot back then, 20 years ago, and to this day I rank that gun as probably the most accurate (in my hands) handgun I ever shot, up there with a particular old West German Sig P220.

    I wondered if it was possible that my thumbs were pushing on the side of the slide while cycling the subsequent shots, so it is interesting to see that this can happen in a Ransom rest, too.
     
    Last edited: May 26, 2015
  21. leadcounsel

    leadcounsel member

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    The situation of a round in a chamber will be the same - or only a minuscule different - depending on hand racking versus recoil racking.

    Sounds like user error - DA vs SA and different trigger pulls type of thing.

    I'd need to see compelling evidence to think otherwise.
     
  22. Walt Sherrill

    Walt Sherrill Member

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    Compelling evidence...

    That's why I mentioned Ransom Rest tests. (And the link I posted showed some differences, but they didn't explain how the first round of the test was chambered...)

    In theory, I can see how a round chambered MANUALLY might not have the same lockup as a round chambered by slide action: the forces won't be the same. That said, I KNOW that some folks starting with a DA/SA gun will get different results between the first and second shots because of the SHOOTER, not the gun. But in the case of Ransom Rest tests and a SA gun (1911), that's harder to explain away... and in the linked article, only ONE of the guns didn't show a difference...

    That suggests that in some cases, lockup may be the issue -- but I'm pretty sure that the SHOOTER is often part of the problem, too.
     
  23. 9mmepiphany

    9mmepiphany Moderator

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    This has come up a couple of times already in this thread and is really a non-factor.

    First: It occurs with the 1911...often enough that there is a thread about it on a 1911-centric forum

    Second: The first shot, after the first round is chambered, is fired, from a DA/SA pistol, from the condition that chambering the round left it...in SA

    Third: It happens occurs with a Glock, which has a consistent trigger stroke

    Forth: It occurs when shooting off a rest with the shooter aware enough to pay attention to it...Post #20

    I don't know that many people who own Ransom Rest. The one I do uses it to compare accuracy when developing new loads and has been doing it for 30+ years.

    His normal procedure is to throw away the first round when measuring groups...after the rounds to settle the gun into the rest...because he has found that that first round will strike in a different location to the following 5 rounds (he loads 6)
     
  24. js2013

    js2013 Member

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    "See the post in this thread by Jerry Keefer (#7):
    http://www.1911pro.com/forum/viewtopic.php?f=7&t=2902
    He is a respected Bullseye smith and has studied this issue and provides some insight.
    Joe"

    That's good info. Thanks!

    I remember when I started shooting competition and we had a old HM on the team. Every time his 8/9th shot he'd call a 10 or X, but it'd be an 8, always at the same spot. All others shots were on call then the next 8/9th shot again would not be on call. Most folks would just figure they screwed up, but he knew his call was right. He finally figured out the problem.
     
  25. Walt Sherrill

    Walt Sherrill Member

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    Yes... but only if there was a shot BEFORE that round.

    IF the first round was chambered manually, as when loading an empty weapon, there could be a difference in lockup -- as the forces applied when manually cycling the slide and the forces applied as a result of a round fired could be significantly different (and, perhaps, even the distance the slide travels could be different). That seems to be the reason that the first shot, in Ransom Rest tests, as explained in your response above, are discounted.

    I agree with the other points you cited above.

    With regard to leadcounsel's comments above, there seems to be enough different examples of first rounds going astray, with both SA and DA/SA guns to suggest that it's not always or only shooter error. That is not to say that shooter error couldn't be MORE of an issue with some guns and some shooters than a lack of consistent slide movement and lock up between first and subsequent shots. (I worked as one of the folks doing target scoring in many IDPA matches over the years and saw, time and again, first rounds going to different places than intended (while subsequent rounds were better-placed) with many DA/SA guns starting from hammer down. But more experienced or more skilled shooters made the differences less obvious.)

    .
     
    Last edited: May 27, 2015
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