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180gr .40 or 185gr .45 acp for penetration?

Discussion in 'Caliber Corner' started by DFin, Aug 28, 2010.

  1. DFin


    Mar 22, 2008
    Does anyone know if 185 grain .45 acp has better, worse or similar penetration when compared to 180 grain .40? Penetration of humans, animals, windshields, car bodies etc. from handguns with similar barrel lengths.
    Last edited: Aug 28, 2010
  2. Brucev


    Jul 19, 2009
    It all depends. Of course it does! But, all things being equal, a 180 gr. .40 bullet will give better penetration than a 185 gr. .45 bullet. The sectional density of the .40 is a little bit better than then .45 so at equal velocity, with equal construction, etc., the .40 will penetrate better.

  3. fredj338


    Dec 22, 2004
    Very true, SD, w/ bullets of the same design, allows the 40 greater penetration @ equal vel. The 180gr/40 was designed to replicate 230gr/45 performance. Driven @ the same vel, JHP work about the same in both. The 155gr/40 is closer to the 185gr/45 in performance & maybe a bit better as it can be driven faster w/ less recoil. I still prefer the 45acp, but mostly because I prefer the 1911 platform.:dunno:
  4. novaDAK


    Apr 17, 2006
    The 180gr .40 most likely. Better sectional density.
    Last edited: Aug 29, 2010
  5. Ak.Hiker


    Feb 8, 2005
    Homer Alaska
    In most designs that I can think of the 180 grain in 40 S&W will offer deeper penetration than the 185 grain 45 acp. The one exception may be the CorBon 185 grain DPX +P 45 acp all copper load.
  6. DocKWL


    May 15, 2009
    All of the posts above are correct.
  7. DFin


    Mar 22, 2008
    I did not know that the 180gr/.40 was designed to replicate 230gr/.45 performance. I just assumed that the 185gr/.45 with higher velocity would penetrate better than slower .230gr/.45. What is the benefit of 185/.45? Was it designed because the higher velocity will be more likely to cause hollow points to expand?
  8. RottnJP

    RottnJP Lifetime Member

    Feb 1, 2005
    Exactly. All other things being equal, as they say, penetration is directly related to the sectional density, which is bullet mass per unit area. Going the other direction, the lighter bullets are going faster, and intended to open up more robustly. The thing you have to be careful of is the "all other things being equal" assumption, because bullet design can change things completely. But, understanding this may help you select bullet weights for caliber that meet your performance goals, rather than falling into the "faster/slower/heavier/lighter/whatever is always better" trap.

    In the case of the "slow" 230 gr .45 ACP bullets, their design accounts for the lower velocity. So, all things aren't equal, and good 230 gr. HP's have a good track record, and that's what I have in my .45's. Going to other calibers, I like 165 gr in .40. To me, it's a nice balance of velocity and penetration. But for my .380, I knew I wanted a heavy bullet for the caliber, with a low expansion bullet, to get the desired penetration. Yay DT XTP. Or say for a 10mm- 165 is going to tend to open up faster with the extra velocity, so you may want to go with 180 grain. But if you're going hunting with it, you might bump it up to a 200 gr XTP to get the extra penetration.
    Last edited: Aug 29, 2010
  9. fredj338


    Dec 22, 2004
    Back in the ealry days of JHP designs, it was tough to get reliable expansion from a 230gr bullet going 850fps. So the 185gr JHP came to be. At 1000fps+, it hit the then magic threshold of 900fps+ for reliable expansion w/ a jacketed bullet. Todays 230gr designs will expand within their vel envelope just fine. The advantage to me of 185grJHP are in smaller/lighter 45s where going to a 230gr+P raises recoil to a level that affects fast/accurate followup shots.