Heavy vs Light Bullets in Short-Barreled 9-mm Pistols

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Crash
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Heavy vs Light Bullets in Short-Barreled 9-mm Pistols

#1

Post by Crash »

Couple of questions regarding heavy vs light bullets in short-barreled 9mm pistols:

1. I read somewhere that it's better to use heavy bullets vs light bullets in short-barreled pistols. The theory is that since they lose a lot of velocity vs long-barreled pistols that lighter bullets won't expand properly, so go with the heavy ones to get deeper penetration. There may be something to this since both Federal and Speer produce loads for short-barreled pistols using heavier bullets--Federal uses a 150 gr in their Micro load and Speer uses a 135 grain bullet in their short-barreled load.
2. This probably applies to full-sized pistols, too: does the momentum of a heavy bullet load tend to damage/wear a pistol faster than the energy/velocity of a light bullet load?

Thanks for your help,

Crash

parabelum
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Re: Heavy vs Light Bullets in Short-Barreled 9-mm Pistols

#2

Post by parabelum »

In my P365 I run lighter loads during range times with occasional hotter mag or two. My carry has been plain ol’ 147gr for a long time though.

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Crash
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Re: Heavy vs Light Bullets in Short-Barreled 9-mm Pistols

#3

Post by Crash »

Rob72 wrote: Wed Oct 21, 2020 3:27 pm "Short barrel" usually means less than 4", generally 3.5" or so.

Are you shooting a revolver or auto?

Revolvers lose the most energy, and will hit lower to POA, with lighter bullets.

Most modern pistol rounds are built around the 4-5" auto, and, all other things being equal, 1/2" either way is not going to make that much difference, i.e., they will all generally expand to some degree, barring something clogging the cone before penetrating the target. Do bear in mind, handgun rounds are not rifle rounds, and anything less than 1500-1800 fps has a reasonable chance of not expanding.

Heavier bullets at higher velocities will wear your pistol, as will any +P/high pressure/max velocity round. You'll want to watch, and possibly adjust your mainspring weights to handle a steady diet of hot loads.

Heavy subsonic rounds (145 gr .45 ball) and mid-weight moderately supersonic(125gr 9mm) rounds are standard fare, and are well within design specifications.


There is all kinds of debate, but, generally, 120-125gr 9mm +P and 140-ish gr .40/.45 +P has dropped a lot of bipedal meat, very consistently.
Rob72,

Sorry, should have made that clearer. I'm shooting a Springfield Armory Hellcat with a 3" barrel, which makes it an inch or more shorter than a "standard" length barrel.

I shot 100 rounds of mixed HP rounds today and they all fed, fired, and ejected with no problem. The Federal +P 124 gr HST HP and the Speer Gold Dot +P 124 HP were the most accurate, although the recoil was pretty snappy (not painful, but noticeable). I probably won't carry +Ps regularly, but that's all I had.

What I read was that heavier bullets, even if not at higher velocities, will wear your pistol more than lighter bullets at higher velocities. Supposedly, the greater momentum of the heavier bullets, even at lower velocities, wear the pistol more than the lighter bullets, even if they have more kinetic energy.

Crash

Mike S
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Re: Heavy vs Light Bullets in Short-Barreled 9-mm Pistols

#4

Post by Mike S »

Crash wrote: Wed Oct 21, 2020 5:50 pm
Rob72 wrote: Wed Oct 21, 2020 3:27 pm "Short barrel" usually means less than 4", generally 3.5" or so.

Are you shooting a revolver or auto?

Revolvers lose the most energy, and will hit lower to POA, with lighter bullets.

Most modern pistol rounds are built around the 4-5" auto, and, all other things being equal, 1/2" either way is not going to make that much difference, i.e., they will all generally expand to some degree, barring something clogging the cone before penetrating the target. Do bear in mind, handgun rounds are not rifle rounds, and anything less than 1500-1800 fps has a reasonable chance of not expanding.

Heavier bullets at higher velocities will wear your pistol, as will any +P/high pressure/max velocity round. You'll want to watch, and possibly adjust your mainspring weights to handle a steady diet of hot loads.

Heavy subsonic rounds (145 gr .45 ball) and mid-weight moderately supersonic(125gr 9mm) rounds are standard fare, and are well within design specifications.


There is all kinds of debate, but, generally, 120-125gr 9mm +P and 140-ish gr .40/.45 +P has dropped a lot of bipedal meat, very consistently.
I shot 100 rounds of mixed HP rounds today and they all fed, fired, and ejected with no problem. The Federal +P 124 gr HST HP and the Speer Gold Dot +P 124 HP were the most accurate, although the recoil was pretty snappy (not painful, but noticeable). I probably won't carry +Ps regularly, but that's all I had.

Crash
Crash,

If this pistol is your EDC, I'd recommend loading your EDC magazines with either of those.

I'm not well read on what causes more wear on the rifling, however for self defense purposes both of those are solid.

flechero
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Re: Heavy vs Light Bullets in Short-Barreled 9-mm Pistols

#5

Post by flechero »

The reason lighter bullets are pushed to higher velocity is to make up the energy to run the gun... it takes a lighter bullet a higher velocity to generate the same amount of energy. So no, heavier bullets (at standard pressures) won't wear the gun more than it's lighter, faster counterpart.

JHP's are made to expand in a certain velocity range and therefore may or may not work as advertised if you are over or under that range. I run my carry ammo through a chronograph and even with a 3" PF-9 (my smallest pistol) I'm in the range for reliable expansion.

Check with your ammo's mfr to see what they recommend and then shoot through a chrono to validate your results.

As an example, here is the Hornady chart for the XTP projectiles...
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XTP recommended velocities.docx
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MaduroBU
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Re: Heavy vs Light Bullets in Short-Barreled 9-mm Pistols

#6

Post by MaduroBU »

I use heavier bullets in general (for higher BC in rifles, for better performance for a given barrel in pistols, and for better patterns at range in shotguns), but in particular in shorter barrels given the greater inertia resisting the initial impulse from the powder which should result in a greater area under the pressure vs. time curve inside the barrel. In pistols with small amounts of very fast powders, you quickly reach the point of diminishing returns for barrel length, with nearly all pistols gaining no additional velocity beyond 14" of barrel. http://ballisticsbytheinch.com/ is a great resource for this, and shows that the heavier (in that case 180 grain) .40 S&W loads stop gaining velocity in a >9" barrel, while 125 grain 357 Sig loads stop gaining velocity in a 14" barrel. Note that I mean literally "no additional velocity", with the increase in velocity per inch becoming progressively smaller as barrel length approaches that limit, so that the point of diminishing returns for a system wherein shorter barrel length is desirable is somewhat less (and somewhat subjective). The observed trend from that data is that the heavier the bullet in a given caliber, the shorter the barrel capable of producing the maximum possible velocity.

For instance, in my X5 with a 5.7" barrel, I use a .357 Sig pushing 147 grain XTP at ~1400 FPS, whereas in my P239 I use a .40 S&W pushing a 200 grain XTP at 950 FPS. That works out to the .40 having a power factor (PF, equal to momentum) of 191 and an energy of 401 lb-ft while the 357 load has a power factor of 205 and an energy of 640 lb-ft. The 357 would lose a large amount of velocity in the 3.6" P239 barrel while the .40 would gain comparatively little from the 5.7" P226 X5 barrel. Thus switching the loads between guns (which is just a barrel swap) would produce a bunch of muzzle blast from the P239 AND much less performance while the .40 load in the P226 X5 would gain little additional performance from a barrel 158% as long. The 357 Sig load CAN carry significantly more energy IF AND ONLY IF the larger powder charge has the barrel length in which to act efficiently. For an auto-pistol, grip size dictates how large the rounds can be unless you have sasquatch hands (in which case you can just carry a DEagle and laugh at the rest of us as we scurry meekly away).

The cartridge and barrel are one continuous pressure vessel, and you cannot consider one without the other. I have a whole other rant on SBRs vs bullpups, but that's for another day.
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