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Barrel length and effect on 9, 40, 357sig, 45

Discussion in 'Caliber Corner' started by Henry's Dad, Nov 6, 2012.

  1. Henry's Dad

    Henry's Dad woof, woof

    In the world of compact/subcompact semi-autos, which caliber is least affected by short barrels? Which suffers most? I'm mainly thinking about 9mm, .40 S&W, .357sig and .45 ACP. Feel free to comment on others as well.

    I'm thinking in terms of accuracy and loss of velocity vs. being fired from a longer barrel.

    I've heard certain rifle calibers suffer less than others when shot from shorter barrels (.308 does better than others, I've read). Just wondering if the same distinction can be made among popular carry calibers.

    Edit: Just found "Ballistics by the inch" thread that should answer this for me. Sorry. Feel free to chime in if you have something to add.
     
    Last edited: Nov 6, 2012
  2. WinterWizard

    WinterWizard

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    I think they all suffer the same. I think it's a myth that some don't suffer as much as others. Less velocity equals less energy and less possibility of violent expansion. Caliber doesn't matter. JMO.
     


  3. CDW4ME

    CDW4ME

    1,575
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    Jun 5, 2009
    USA
    Chrono averages out of a couple of my pistols:
    Glock 32:
    Federal 125 JHP @ 1,332 fps
    Cor-Bon 125 JHP @ 1,380 fps
    Glock 33:
    Federal 125 JHP @ 1,272 fps (-60 fps)
    Cor-Bon 125 JHP @ 1,324 fps (-56 fps)
     
  4. cowboy1964

    cowboy1964

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    U.S.A.
    Yeah, all about the same, or close enough, across calibers. From short barrels I'm more concerned with controllability because of the smaller gun frame and lighter weight.

    However, within a caliber, faster rounds will lose more velocity faster than slower rounds simply because they have more to lose. OTOH, you still have a faster round whereas with a slower round you may be getting too slow (230gr 45 ACP from a 3" barrel is a good example).
     
    Last edited: Nov 6, 2012
  5. SDGlock23

    SDGlock23 Glockoholic

    In any given cartridge the heavier bullets tend to be less effected by barrel length changes than lighter weight ones. A majority of .45's are initially tested from 5" barrels whereas 9mm or .40 for example are often tested from shorter 4" barrels, so you might tend to see less velocity loss in a 9mm or .40 from a shorter 3" barrel as compared to a .45 in a 3" bbl.

    I have chrony tested .40 loads in the 4" G23 and 3" Kahr CM40 and there's not a big difference, in fact some of the 165gr ammo was almost the same. Personally, if I were going to carry a small barreled semi auto it would be in 9mm or .40 since they still retain good enough speed to still get reliable expansion, not that a .45 wouldn't expand, it's just going to be going pretty slow from a 3" bbl.
     
  6. ABNAK

    ABNAK

    729
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    Apr 22, 2005
    Tennessee
    Excellent point. Many folks seem to forget this and wonder why .45's drop so much.
     
  7. ABNAK

    ABNAK

    729
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    Apr 22, 2005
    Tennessee
    This serves to bolster my theory, after many years of chronographing rounds, that the oft-mentioned "50fps loss per inch of barrel length" is actually "50fps loss per half inch of barrel length", at least as far as handgun ammunition is concerned.

    The above does not apply to heavy-for-caliber loads as they tend to lose less velocity. Mainly applies to lighter or mid-range loads with some speed behind them.
     
    Last edited: Nov 6, 2012
  8. Zombie Steve

    Zombie Steve Decap Pin Killa

    18,083
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    May 31, 2007
    Old Colorado City
    .45's drop a lot?

    Winchester brass, CCI large pistol primer, 6.6 grains WSF, 230 grain XTP, 1.210" OAL:

    10 shot averages / chrono @ 10 feet.

    5" 1911 (TRP): 856 fps
    4.4" Sig P220: 824 fps
    3.78" G30: 827 fps
    4.6" G21: 876 fps
     
  9. cowboy1964

    cowboy1964

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    U.S.A.
    Yes, a 230gr from a 3" will come in around 750-780 fps. A good JHP should still work but that's getting mighty slow IMO. Though I'd be more concerned about the infamous feeding problems in 3" .45s really.
     
    Last edited: Nov 6, 2012
  10. SDGlock23

    SDGlock23 Glockoholic

    Looks about right, the big 230gr isn't going that fast to begin with and it doesn't react as much to bbl length as would a 185gr or 200gr. I've ran factory 230gr FMJ through a G30 and it did high 700's to right around 800 fps. Chop off another 3/4 of an inch and that's not going to help matters.

    Another example, I loaded up some 200gr JHP in my 3" Kahr CM40 and it averaged 975 fps. The same load from the 5.3" G35 was only 90 fps faster..with almost 2.5" extra bbl.
     
    Last edited: Nov 6, 2012
  11. ABNAK

    ABNAK

    729
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    Apr 22, 2005
    Tennessee
    I was referring mainly to factory loads which are generally spec'd to a 5" barrel.

    Of course it's relative too: like others have said, a .45 isn't a screamer to start with so even a *modest* drop could put you in the upper 700's, which I'd not really be comfortable with personally.
     
  12. fredj338

    fredj338

    21,945
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    so.cal.
    It's not a myth, has to do with burn rate, pressures & caliber. The 45acp, being low pressure, suffers the least loss per inch than the other service calibers, also shows the least gain going to a longer bbl. Having said that, bullet design is more important than vel loss. Todays bullets have a wider vel range for reliable expansion. Stick w/ proven designs & the diff in bbl length should not be an issue.
    Most of the 230gr JHP I have run still make right @ 800fps in my OM 3 1/2" bbl. The 200gr XTP almost 900fps. The BlackHills 124grXTP+P does 1220fps in my G26 vs 1265fps in the G17. I don't worry about it much.
     
    Last edited: Nov 6, 2012
  13. JW1178

    JW1178

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    It seems that it's a percentage ratio, so the "50FPS" rule, although a good standard when giving rough estimates, is not really accurate. Slower rounds lose less FPS, but lose about the same percent.

    It does seem though that rounds that use the most powder and/or higher pressure loadings such as the .357mag and 10mm really take advantage of extra barrel length.
     
  14. WinterWizard

    WinterWizard

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    I don't disagree. But I think the difference across calibers is so small as to be insignificant.

    I do agree that 3.5" is about as short as I'd care to go in .45. I think the .45 suffers below that length barrel. I would never own a 3" .45. Even the 3.3" Springfield XDs is too short for my liking. My opinion is that if you are going to carry something that small, go with 9mm or .40.
     
    Last edited: Nov 7, 2012
  15. SCmasterblaster

    SCmasterblaster Millennium Member

    18,237
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    Hartford, Vermont
    My first thought was that .45 ACP is the cartridge least affected by barrel-length reduction.
     
  16. CDW4ME

    CDW4ME

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    USA
    Another...

    Glock 19:
    Winchester Ranger T 124 gr. +P @ 1,212
    Winchester Ranger T 127 gr. +P+ @ 1,238

    Glock 26:
    Winchester Ranger T 124 gr. +P @ 1,162 fps (-50 fps)
    Winchester Ranger T 127 gr. +P+ @ 1,182 fps (-56 fps)

    Last one (comprehensive reply now)
    45 acp handload: Hornady 185 XTP with 10 gr. AA#5, Winchester primer, OAL 1.210" taper crimped.......... (anticipation building)

    5'' barrel 1911: 1,034 fps
    Glock 30 SF: 970 fps (-64 fps)
     
    Last edited: Nov 8, 2012
  17. Ljutic

    Ljutic

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    Jun 8, 2011
    So far in my testing, I've been pretty amazed at how the velocity of .40 holds up as barrel length decreases.

    I've also posted two short barrel 45 tests recently that show 3.3" is plenty of barrel for good terminal performance. Should be even better in the G36.
     
    Last edited: Nov 8, 2012