What happens to 9mm FMJ when shot out of a 16" barrel?

Discussion in 'Rifle Country' started by twofewscrews, Apr 21, 2022.

  1. twofewscrews

    twofewscrews Member

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    I own a Ruger PC9 and was considering purchasing/stocking up on some HP ammo for self defense/hunting/SHTF. After a bit of research, in particular the LuckyGunner article titled Self-Defense Ammo for Pistol Caliber Carbines as well as Paul Harrell's Youtube video titled Ammo Selection for 9mm Carbines, I settled on some flavor of 147 grain HP ammunition for use in my PC9. This was due to the fact, at least as far as the information I could find, that when a 9mm 115 grain or 124 grain HP is sped up it loses effectiveness. The increase in speed leads to uncontrolled expansion or fragmentation of the bullet. The 147 grain HPs did not see the same velocity gain from a 16" barrel thus it's performance was not affected.

    This made me wonder, does speeding up a 9mm FMJ 115 grain, 124 grain, or 147 grain bullet cause them to lose effectiveness/act in a way they were not intended to act?

    Do FMJs flatten or fragment like HPs when pushed past the velocities they were designed to operate at?
     
  2. N555

    N555 Member

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    Typical handgun loads don't see a big velocity increase when fired in a carbine length barrel.
    I could load up some insanely hot sten only FMJ ammo and try it out, I was able to get 124gr bullet going nearly 1,600fps with a compressed load of AA9 out of a 9 inch barrel.
    I can blow a 124gr HP to bits at that velocity on water jugs.
    But you are not going to find any factory ammo loaded like that.
     
  3. twofewscrews

    twofewscrews Member

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    As I understand it the velocity increase when using a carbine length barrel to fire 9mm hand gun rounds is typically in the 100 to 200 fps range. When using HPs, at least in the case of 9mm HPs, the velocity increase they do see is enough to cause uncontrolled expansion and/or fragmentation of the bullet.

    I wasn't looking to find ammo loaded to such specs, just curious if a velocity increase on a FMJ would have a similar effect to a velocity increase on a HP, which to my understanding is to make it less effective not more effective.
     
  4. FL-NC

    FL-NC Member

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    I don't believe a FMJ would do anything dramatic as far as expansion or frag to the projectile when fired into a human.
     
  5. jak67429

    jak67429 Member

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    I can tell you factory 124 or 115 fmj out of a ruger pcc does not deform much hitting a bowling pin. It does hit harder than out of a 5 in pistol barrel. not a lot but noticeable.
     
  6. wesmonster

    wesmonster Member

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    Check Ballistics By The Inch site, they have all the data you need.
    Most 9mm std. loads pick up another 200fps out of a 16” barrel if I recall. Basically at +P levels out of a 4” barrel.
    FWIW, I used to buy bulk reloaded 9mm 147 gr +P for my 16” PCCs, never saw any indications of the bullet deforming or breaking apart in flight. I HAVE heard of some of the newer SD loads, the ones under 100 grains, breaking up, but never plain ol fmj.

    I’m also betting that if the bullets in the 9mm surplus ammo marked ‘Submachine gun use only’ for UZIs are just plain copper over lead, you can’t load a 9mm hot enough to sent that bullet fast enough to damage it in flight.
     
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  7. ms6852

    ms6852 Member

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    I believe that rifle twist also has to do with stabilizing the bullet. If the twist is fast the jacketing of the round may engage only part way down the barrel and as velocity increase the bullet may skid the rest of the way where the grooves may shave some of the jacketed material and thus people report that the bullet exploded before hitting the target. So finding the correct balance between bullet length and rifle twist is key.
     
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  8. LoonWulf
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    LoonWulf Contributing Member

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    147jsp(doh, should say FMJ) do not expand when driven to 2300 from a .350 legend.
    147jhps turn into grenades.

    Id stick with 124-147jhps in a 9mm defensive carbine.
     
    Last edited: Apr 23, 2022
  9. 22250Rem

    22250Rem Member

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    Very interesting topic, as I own a Ruger PC carbine, a Glock 19, and a chronograph. Couple summers ago I ran 3 different 9x19mm FMJ loads and 1 JHP load out of the PC carbine over the chrono and then chrono'd the same ammo out of my Glock 19. All four types of ammo gained velocity when fired from the PC carbine, which is what I expected, but not a lot in 3 of the 4 tests. Dug out my notes and here's the results. All results are averages of five rounds...
    Test # 1 : Wolf steel case 115 gr. FMJ : Glock: 1128 fps vs. PC carbine: 1368 fps; A gain of 240 fps, ( biggest gain).
    Test # 2 : Blazer Brass 115 gr. FMJ : Glock: 1155 fps vs. PC carbine: 1166 fps; a gain of 11 fps ( smallest gain).
    Test # 3 : Speer Lawman 147 gr. FMJ: Glock: 1037 fps vs. PC carbine: 1065 fps., a gain of 28 fps.
    Test # 4 : Wolf Gold 147 gr. JHP: Glock: 934 fps vs. PC carbine: 952 fps., a gain of 18 fps.
    Barrel lengths : PC carbine - 16.12" (Ruger spec), Glock 19 - 4.02" ( Glock spec).
    Forgot to record the temperature but it was a mid-summer afternoon so probably at least 80 something deg. F.. It was surprising that all gains except Test # 1 were smaller than I was expecting with that much difference in barrel length. But then; I had never chronographed pistol rounds in such different platforms. Just got the idea from seeing two 9mm guns side by side and wondering about things like that. Satisfied my curiosity, anyway. Far as I know, ( ? ), all these bullets are still within the velocity range they were designed for except in test #1 there wasn't much difference between the PC carbine and the Glock velocities. Test # 1's 115 gr. FMJ @ 1368 fps would be closest to whatever is considered too fast for a 9mm pistol bullet; whatever that might be. Anybody out there know stuff like that ? Just curious. I love being able to tap into the vast amount of collective knowledge here on THR.
     
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  10. twofewscrews

    twofewscrews Member

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    In my OP I mentioned a LuckyGunner article Self-Defense Ammo for Pistol Caliber Carbines.
    These are the results using Speer Gold Dot 124g and Speed Gold Dot 124g +P from a Ruger PC9 and a Beretta 92 Elite LTT

    This is from the Beretta
    gold-dot-expanded.jpg

    This is from the PC9
    gold-dot-deformed.jpg

    He found similar results in velocity gains
    LGV.jpg

    The 147 grain bullets stayed the closest to their original operational speed and performed as they should.

    What I want to know is, when you push 9mm FMJs faster, are they affected in the same or similar manner as when you push 9mm HPs faster? Ie do they act in a way they were not designed to act?
    Its would seem that perhaps HPs are designed to operate at specific speeds or function the best between certain speeds whereas FMJs function basically the same at most speeds.
     
    Last edited: Apr 21, 2022
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  11. Dave DeLaurant

    Dave DeLaurant Member

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    One more source of information:

     
  12. NIGHTLORD40K

    NIGHTLORD40K Member

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    Most 9mm loads hit peak velocity between 9" and 12" and start to slow down after that- this is why military subguns usually have barrels in that range.

    IIRC, most .22LR will peak between 14-16" and lose quite a bit of velocity in 20-24" barrels.
     
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  13. CarJunkieLS1

    CarJunkieLS1 Member

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    I chose Winchester 147gr+p Ranger Bonded Item # Q4463 as my preferred load in my Ruger PC Carbine. I was surprised that it gained very little velocity from the 16" barrel but that's OK it should perform very well at "box flap" velocity.
     
  14. 22250Rem

    22250Rem Member

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    This thread reminded me of discussing my informal 9mm chronograph session with a gunsmith / LGS owner about a week later. I had forgotten all about that. He stated that most 9mm ammo is designed with just handgun length barrels in mind as that's where most all 9mm ammo gets used. Therefore the ammo companies velocity target is based on the shorter barrels so it's loaded to meet that spec. In a longer, say 16" barrel, it may actually lose a little velocity because the bullet may have lost a few fps by the time it travels through 16 inches of tight barrel. I noticed that in one of the results from that Lucky Gunner testing video. If they were to load it hotter it would be a waste of powder in a shorter barreled handgun and possibly cause too much muzzle flash. Most of the ammo I was chronographing had probably reached its peak velocity in the first 8 to 12 inches of barrel and had lost a few fps by the time it cleared the muzzle and sailed over the chrono.. Or at least I'm starting to think along those lines now.
     
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  15. JohnB-40

    JohnB-40 Member

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    Norma sells Envy 124gr FMJ which is advertised at 1345 fps. It has been a while (Xmas) since they have had it in stock. Amazingly accurate at 50 yds,I can feel the difference from regular 124gr in the recoil with my Ruger PCC. If you see it for sale on their online store,its well worth scoring some.
     
  16. Mosin77

    Mosin77 Member

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    I wouldn’t expect an FMJ load to do anything different. FMJ is pretty inert, for want of a better word. Maybe if you loaded a 115gr in a rifle and shot it at 3500fps it would do some interesting things as the jacket completely fails to maintain integrity at a velocity far and away beyond its design envelope, but at the very modest gains of a longer barreled carbine, it will behave exactly as from a pistol in terms of physical integrity. It may have a slightly different terminal effect (or not) but this will only be due to the slight additional velocity.

    A hollowpoint on the other hand is designed to operate in a certain way and has a very narrow window of velocity in which it performs optimally. Too little velocity (too short a barrel) and it won’t expand, or won’t expand fully. Too much velocity and it will overexpand, causing less than optimal penetration or a less than desirable wound cavity. They’re pretty reliable these days but inherently not very adaptable to different velocities.
     
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  17. bfoosh006

    bfoosh006 Member

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    FWIW, here is a bunch of chrono data from my Colt Pattern 16" PCC. And bonded bullets, tended to be more accurate out of my barrel. YMMV
    On a side note, 9MM out of a 16" barrel has a very similar trajectory like a 22LR from a 16" barrel.
    https://www.ar15.com/forums/ar-15/16-9x19-AR15-Carbine-Chrono-Test--129-OEM-rds-52-more-added-May-7th-/16-712312/

    As for the original FMJ question, there won't be much meaningful difference in ballistic gel, but smacking a bone with the added velocity is going to be more dramatic.

    I ended up choosing Fed. 135gr +P Bonded HP , for its accuracy, speed , and bonded bullet.
     
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  18. Jim Watson

    Jim Watson Member

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    I recall that the original application for a 147 gr 9mm was "sentry elimination" from a silenced SMG.
     
  19. sequins

    sequins Member

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    Those 124 grain loads look beautiful. Blooming as much as possible without shedding weight is the best. The 40sw bullets in a 10mm work great too with the extra velocity.

    Unless we're losing retained weight these PCC expansions look good to me.
     
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  20. Pat Riot
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    Pat Riot Contributing Member

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    Thanks for posting your experience with 9mm from a pistol and carbine. I was a little surprised by your numbers. I was thinking the Blazer and Speer ammo would have had a bit more juice from the carbine. Very interesting. Thanks.


    @wesmonster mentiobed BBTI. Here’s a link.
    http://ballisticsbytheinch.com/9luger.html

    BBTI pretty much listed ammo I never use, but I appreciate what they did.
     
  21. Mosin Bubba

    Mosin Bubba Member

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    Same thing I've seen with my Sub 2K.
     
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