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Interesting Article on Short Barreled 1911's

Discussion in 'Handgun Discussion' started by Cougfan2, May 28, 2010.

  1. Cougfan2

    Cougfan2 Hillsboro, OR Well-Known Member

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    I found this artcle by Bruce Gray on his web site regarding Short Barreled 1911's and some of the inherent problems with them. Thought y'all might enjoy the read.

    Physics and short .45 caliber pistols – a discussion
    February 1, 2010 by Bruce Gray · 1 Comment
    Let’s discuss some of the factors affecting the functioning of pistols in general, and short 45’s in particular. To contribute to this discussion, head over to SigForum and join in.

    Let’s imagine a theoretical pistol, say a .45 caliber firing a given load, in which magazine timing efficiency and lockup were basically constant values. This means that the magazine requires a minimum period in which to present rounds before the breechface, and that the barrel and slide remained mechanically locked together for a set travel.

    Let’s say that the variables at play are barrel length and spring tunnel length in proportion; slide mass; breechface over-run (it’s rearward travel past the magazine that, in part, dictates how much time the magazine is given to do it’s job); and recoil spring rate / weight.

    Shortening the barrel length reduces total reciprocating mass, while increasing bore pressure at the muzzle which drives slide velocity as a function of the jet effect of expanding gas behind the bullet.

    Thus, if we make our theoretical .45 shorter, we get faster unlocking and higher slide velocity due to reduced mass, AND even more slide velocity driven by higher residual bore pressure. Besides rendering our theoretical pistol unpleasant to shoot, excessive slide velocity has obvious consequences in the form of increased wear and breakages, plus the possibility of recoil-induced magazine malfunctions like double feeds and the like. We’ve agreed that in this pistol we can’t decrease slide velocity by increasing lockup travel to (partially) compensate for reduced slide mass.

    Yet, our shorter pistol has room for an even shorter recoil spring that is taxed to do even more work in less travel and with fewer coils in a shorter space. So, an obvious answer is to use a heavier-rated spring to slow that slide down. It makes sense.

    There are some problems and limitations at work against us here, however. First, our shorter spring needs to exert even more pressure in battery to attenuate the increased speed of unlocking from our lighter slide; to accomplish this, we can open up the coil spacing but at the expense of significantly reduced service life as we see with the various small 1911-style guns. One workaround: the multui-strand spring that SIG has pioneered already. However, that spring’s large net wire diameter limits how short it can go. Another? The flat-wound spring type.

    So, let’s say we can engineer a trick 26-pound spring that gives us all the closing pressure against that light slide in battery we want, and slows down that gnarly slide velocity like a champ. Great!

    The problem is that we’re up against another variable and one of our constants: we’ve had to shorten slide stroke considerably to arrive at this small package, and thus have reduced breechface over-run. Along with our ultra-strong recoil spring, we now aren’t giving the magazine enough time to function reliably.

    Our choice of .45 ACP, being heavier and with a less-optimal transfer factor compared to other rounds like, say, 9X19, makes this timing even more critical.

    So, we decide to lose the garage-door spring and back off the tension / rate just enough to allow the mags to feed, without permitting excessive wear and breakages from too much slide speed. Great! Our theoretical test gun survives a torture test in fine form on our test range, fed by a stack of new mags loaded by assistants.

    Why, then, do our imaginary customers complain that their pistols start in with FTF’s after a few hundred rounds or so? That likely has to do with the difference in fatigue rates between magazine and recoil springs. The same physics are at play when we shorten the magazines, and magazine springs, as well. Unlike our torture-testers, our customers have only a few mags to work with, and as these mags take a set they no longer can keep up.

    Yet another factor needs to be considered: extractor tension. Our imaginary light slide, short barreled pistol unlocks quickly with higher residual bore pressure, and thus requires more positive extractor tension as a hedge to overcome increased case adhesion forces during extraction.

    Yet, that light slide carries with it much less momentum during the feeding cycle, and we can’t get as much closing pressure from that short spring to overcome the resistance that our increased extractor tension exerts upon the case rim as it tries to slide up the breechface, much less from a marginally-timed, short magazine with a less-than-adequate mag spring. Thus, the classic 3-point FTF jam we see all the time in short .45’s.

    So, we can try another workaround to deal with feeding issues caused by both higher extractor tension and a reduced magazine timing window: we increase magazine spring tension to compensate. That, however, also has consequences as the slide has to overcome more resistance as it strips rounds out of the feedlips.

    That, in brief, is an explanation of some of the fundamental problems that make shortened pistols so problematic. The tension between these factors is difficult to balance. If some of these factors seem familiar to your experience with various short .45’s, I hope it will help explain why I generally try to steer folks away from them.

    I hope to lend some technical perspective to the subject of short pistols, and hopefully help explain my preference for at least somewhat longer guns. In a world of highly critical, perhaps over-engineered handgun designs, I believe a few extra coils of recoil spring, a bit more slide mass or a little bit longer slide travel can make all the difference.
     
  2. MrNiceGuy

    MrNiceGuy between springfield and shelbyville Well-Known Member

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    The entire article is predicated on this one assumption. To gain anything from this you'd have to first agree that shortened 1911's are problematic... which I do not.

    The last two paragraphs really should have been at the beginning of his ramblings.
     
  3. DeLorean

    DeLorean Washington/Oregon Member

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    I have heard this before. Interesting take on it and something to consider.
     
  4. Cougfan2

    Cougfan2 Hillsboro, OR Well-Known Member

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    While your experience may be different, I have heard of more problems with short barreled 1911's than 4 1/4" or longer 1911's. This guy is a pretty decent gunsmith and I have seen some of his work. He knows what he is doing.

    For more info about him and his company here is a link.

    http://grayguns.com/

    He is also probably one of the best Sig P Series Gunsmiths around. My boss has a Sig 228 that Bruce did a competition package on that is phenomenal.
     
  5. Outrider

    Outrider Oregon Active Member

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    Larry Vickers, another a highly regarded 1911 pistol smith (top tier competitive shooter, and former Delta guy) frowns on shorter barrel 1911 pistols. There are many others at the top who don't like them as well. The more you deviate from the standard 1911 barrel length, the less reliable the pistols are as a group.

    Feel free to research it. People who do the top work know 1911 pistols with short barrels are problematic.
     
  6. wichaka

    wichaka Wa State Well-Known Member

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    He's pretty much spot on. The shorter 1911's can be finicky!
    They do everything a full size 1911 has to do, but in a shorter amount of time, so getting everything right can try the best of patience.

    One thing though...there is no such thing as a double feed in a modern day (as well as a 1911) auto loader. Its an AR platform problem, specifically the magazine, which are capable of doing it. The proper term is "Fail to extract"
     
  7. PinkhamR

    PinkhamR Altus, Oklahoma MSgt, USAF (Retired)-FFL Lifetime Supporter

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    Agreed re: shorter barreled 1911's and a good read ....
     
  8. Cougfan2

    Cougfan2 Hillsboro, OR Well-Known Member

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    Thanks, I was seriously thinking about going to a 3" barreled STI .45 ACP as a carry gun, but feedback from folks that had them and articles like this kind of sent me in another direction. My SP101 3" and my DW CBOB are still in my carry rotation depending on the situation and the clothing I'm wearing, but i just added a Sig 229 in 9mm to my carry rotation as well.

    I am seriously thinking about sending it to Bruce Gray to have an action job done on it, or I just may hand deliver it and get a little Smallmouth fishing in on the John Day while I'm in Spray. ;)
     
  9. wichaka

    wichaka Wa State Well-Known Member

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    I have a Colt Officers model, and have no problems with it.

    I don't shy away from them, and I don't think all are taboo...but there are some models that are problem children.
     
  10. Cougfan2

    Cougfan2 Hillsboro, OR Well-Known Member

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    Please excuse my ignorance. Isn't the Officers model a 4 1/4" barrel on a shortened grip? Even if it is a 4" model, I think the author was referring to the real short 3" barrels, although he was NOT clear about that in the article.
     
  11. swoop

    swoop Milwaukie, Oregon Well-Known Member

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    Officers is 3.5" commander 4.25 Defender 3.0 Have to agree with Bruce Gray on this. Shorter you go, more trouble you will have with the 1911 :thumbup:
     
  12. wichaka

    wichaka Wa State Well-Known Member

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    I disagree with the "more trouble you WILL have."

    Yep they CAN be persnickety, but that doesn't equate to WILL have problems, which I take to mean that the owner is just waiting for the thing to quit working properly...taint so!

    Generally if they are running properly out of the box, more often than not they will run and run well. If there's a hint of a problem out of the box, the headaches can multiply.
     
  13. wakejoe

    wakejoe Beaverton, OR Well-Known Member

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    Also take round count into consideration.

    One person may not have ANY problems with his short 1911; but he only shoots 50 rounds every few months. While another guy can't keep it working for long, because he shoots 500 a week, or more.

    But, I do not and will not own a 1911 shorter than 5 inches, due to the problems listed in the article. :D
     
  14. swoop

    swoop Milwaukie, Oregon Well-Known Member

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    The trouble I've had with my shorter Colt's has been with recoil springs going south after a few thousand rounds down range. My full size guys are like the energizer bunny they just keep runnin & runnin. :D The officer is part of my carry group, but I keep a eye on the round count..springs are cheap insurance. I know that you have worked on Colt's a lot over the years, so I'll bet that your officer's model has been fine tuned by wichaka. :thumbup:
     
  15. ogre

    ogre Vancouver, WA Well-Known Member

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    Thanks for the post Cougfan2. I enjoyed the read.
     
  16. Cougfan2

    Cougfan2 Hillsboro, OR Well-Known Member

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    My pleasure. It is a topic I have been interested in when I was considering a 3" 1911 as a carry piece. Given feedback from others and the info in the article, while some may have no problems with the really short barreled 1911's, I just don't want to take any chances on a carry piece.
     
  17. MarkSBG

    MarkSBG Beaverton Oregon Well-Known Member

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    Yeah, thanks coug! Good read.

    Personally, I think that the length of a guns barrel is one of the easiest features to conceal, so a long barrel in my IWB is no biggie.

    (Yeah, there are limits to how much I can shove my waistband. :laugh: )
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  18. wichaka

    wichaka Wa State Well-Known Member

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    swoop, yep the shorter versions will eat recoil springs...no doubt there!
     
  19. I-Shoot

    I-Shoot Oregon Bronze Supporter Bronze Supporter

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    That has been my experience. I've only sold two guns because I had consistent feed problems with them -- both were 3" barreled .45's (one was a Kimber Ultra Carry, the other a Glock G36 -- and I told both buyers of the issues I had with them). My conclusion was similar to the articles, that the short stroke of the slide made the timing on feeding more critical than on longer barrels.

    I came to that conclusion partly because I found the guns very sensitive to my standard grip pressure. I have owned over 20 handguns of varied sizes and calibers, and I have developed a "standard" grip pressure that is strong enough that I have no "limp wristing" failures. With the short barreled .45's, I found that holding them much tighter than I usually would (i.e. much tighter than any other handgun I own [Glock, SIG, Walther, Styr, Beretta, HK, etc.]), reduced the number of misfeeds. I didn't feel like retraining myself in terms of my standard grip pressure, so I let them go.
     
  20. sports-shooter

    sports-shooter Seattle East Side Member

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    My experience with the Springfield EMP is not so good. It jams regularly and is very picky with ammunition. I never bothered to solve it, but sometimes I wonder if the shortened barrel is a factor.