Why are the handgun bullets heavier rifle bullets?

Status
Not open for further replies.
P

Propforce

Member
Joined
Sep 19, 2011
Messages
204
Hi THR,

When i look at the bullet weight in popular combat rifles, 52 - 77 gr for M4/ AR-15, 123 gr for AK-47, etc, i started to wonder why are they are lighter than the popular SD handgun ammunition, say 9mm to .45ACP and anyrhing in between.

i've read arguments such as handguns do not genrate high enough muzzle velocity to create the "shock effect", yet at the same time "HP need high velocity in order to effectively expand".

So this got me thinking, what if i load a 55 gr bullet (assuming there is one that fits) on to a 9mm casing, would i be effectively increase its muzzle velocity significantly surpassing the 115 gr? Assuming conservation of KE, if i have the 115 gr 9mm exiting at 1,000 ft/s, i should be able to push a 55 gr 9mm to over 1,400 ft/s. This is in the magic velocity territory of the .357mag. Likewise if i reduce the .45 ACP from 230 gr to (omg!) 55 gr., i can increase its muzzle velocity from 890 ft/s to 1,820 ft/s!

In the rifle calibers, we often see loading a smaller diameter bullet onto the parent casings and producing a much higher velocity and higher ballistic coefficient rounds that has flatter trajectory and longer range than the parent round, for example the .243Win, 7mm-08 from the .308 casings, the .270WIN on the 30-06 casing, etc. If i take a 158 gr .357mag load it with 55 gr .223rem bullet, (i will need to re-barrel of course), i can reach a muzzle velocity to over 2,000 ft/s out of a 4-in revolver!

All these are hypothetical discussion of course. I recognize the pupose of a rifle needs to deliver the energy & mass to 200+ yards. But if the velocity is "king" in the controlled expansion of HP, why not reducing weight of bullets in each handgun caliber, thereby significantly increase its muzzle velocity?
 
Last edited:
But if the velocity is "king" in the controlled expansion of HP, why not reducing weight of bullets in each handgun caliber, thereby significantly increase its muzzle velocity?
Click to expand...
They did that in the 1970's and early 1980's until the Miami shoot out, and then they realized lightweight shallow penetrators and the "energy dump" theory didn't work as well as getting enough penetration to hit something vital.
 
Just guessing, brainstorming:

-surface area of the rear of the bullet effects how much force is applied to it.
-which effects it's acceleration
-smaller bullets would leave the bore at a slower than rifle speed before all the propellant is burnt. They need a greater distance to get up to speed. They might still accel faster than a big pistol round, but they have to get all the way up to rifle speeds before they are effective again. Going slightly faster than a pistol round isn't going to do the trick.
-Big muzzle flash and report. Little power.


Good example. (flame suit on)
5.7mm is as good, or better, in a FN Ps90 than 9mm out of an HK Mp5. 10"+ barrels.

But 5.7mm in a pistol, didn't test better for me, than 9mm in pistols. Close, but not good enough IMO.



Now, would a big, fat .45 even fly right if it only weighed 55g???? I doubt it.

And while unscientific, a .50 muzzle loader makes a pretty good mess of whatever it hits. Is it a 30-06? Naw, but seemed impressive at the time.
 
Last edited:
There's a few necked rounds shot from semi autos already. Nothing as extreme as the idea of a .223 bullet in a large case but they do exist. There's .357Sig, 7.62x25 and the 9x40 wildcat loading used by some IPSC shooters that I've seen. And likely others I haven't.

Looking at the issues of velocity drop in .223 M16 like rifles there's already a large drop as the barrels shorten down to 10'ish inches as seen on some of the shorter varieties. Now you're looking at halving that again? And the chamber pressure from a 9mm or pretty much any other handgun casing isn't going to be anywhere close to the 50K of a .223 or 5.56. So there's even less pressure to push the small area of the backside of that .22 bullet. So you won't achieve much more than .22 Mag like velocities.

Let's look at your idea of a 55gn .45. Aside from the mechanical issues even if you could get a bullet of that size and weight out the end of the bore at some crazy speed it would have all the ballistics of a parachute. There's so little inertial momentum in that much lead or copper and still all the frontal area that you'd see the velocity drop off very sharply. Take for example a tennis ball and a badminton shuttlecock. Both have roughly the same maximum diameter. Yet look at how each "flies" when hit with a full power swing. Your 55gn .45 "shuttlecock" would do the same thing. At something out around 25 to 50 yards I'm thinking that it would no longer have any penetration at all. I'd run the numbers for this "thing" through the Hornady ballistics calculator but I can't even begin to imagine what the Ballistics Coefficient would be for a "shuttlecock" like bullet.
 
To some degree, this was done by going from a .40S&W to a .357 Sig.

The .40S&W goes from ~900 fps to over 1,100 fps by reducing bullet weight from 180 gr to 155 and even 135 gr. Then by keeping the .40 caliber casing but adapting the 124 gr 9mm bullet it boost the velocity to 1,300 fps. "Almost" into the .357 mag category. The .357 Sig has a good reputation as effective man-stopper.

So if this trend holds, (big "if" here), if I load the .223 rem (5.56X45) onto a .357 magnum casing with the same amount of powder & burn rate, would I be creating a .223 "rem. magnum" in a handgun caliber?
 
First of all handgun bullets are not heavier that rifle bullets of the same caliber.

Case in point: The .30-06 bullets run around 170 ~ 200 grs. while the .32 ACP runs around 85 ~100 grs or so.

Consider the old .45 Colt with a 250 gr. bullet vs. the .45-70 with a 500 gr. bullet.

Rifle bullets are longer per caliber for stabilizing spin at high rpm, while revolver bullets are shorter with slower spin. Sectional density, the cross sectional area compared to the weight, plays an important part in exterior ballistics in long range shooting. Rifles are expected to be accurate at ranges out to 500 ~ 600 yards, while handguns are expected to deliver accuracy out to only 200 yards or so.

Bob Wright
 
BCRider, yup was thinking the exact same thing on the .357 Sig and was typing when you posted.

Obviously there are practical mechanical limitation of drastic weight reduction while maintaining caliber diameter. But this can be overcome by necking to a smaller caliber thereby producing a new class of handgun calibers.

I started this when trying to decide the best weight for my .40 S&W going from 180 gr all the way to 135 gr.
 
rcmodel said:
No, you would be creating a .22 Remington Jet.

It was a failure for several reasons.
Most of all, bottle neck cases doesn't work at all well in revolvers due to case expansion locking up the cylinder so it won't turn.

http://en.m.wikipedia.org/wiki/.22_Remington_Jet

rc
Click to expand...
RC, thanks for the link. At least it validates the theory of significant velocity increase, but noted there are other mechanical issues needed to be worked out.
 
"(assuming there is one that fits)"

Therein lies the rub. A 55 gr. bullet won't fit a 9mm case without necking it down from .356" to .224". The .357 Sig is a .356 bullet in a necked down .40 case, but that's one of the exceptions that proves the rule, and the diameter difference in quite small. Typically this doesn't result in a whole lot of increase in velocity. The .45ACP, however, typically loaded with a 230 gr. bullet at a nominal 850 fps, can also be loaded way down to a 165 gr. bullet with a nominal velocity of 1250 ~50% boost.

So some of what you are thinking is possible, but not a lot. And "improvements" often result in perennial debate. That 1250 fps bullet isn't necessarily a better "stopper" than the 230 at 850. And so the debate starts.

With rifle cartridges, necking down is very common and does often result in smaller, lighter, bullets being driven to higher velocities.
 
The
BobWright said:
First of all handgun bullets are not heavier that rifle bullets of the same caliber.

Case in point: The .30-06 bullets run around 170 ~ 200 grs. while the .32 ACP runs around 85 ~100 grs or so.

Consider the old .45 Colt with a 250 gr. bullet vs. the .45-70 with a 500 gr. bullet.

Rifle bullets are longer per caliber for stabilizing spin at high rpm, while revolver bullets are shorter with slower spin. Sectional density, the cross sectional area compared to the weight, plays an important part in exterior ballistics in long range shooting. Rifles are expected to be accurate at ranges out to 500 ~ 600 yards, while handguns are expected to deliver accuracy out to only 200 yards or so.

Bob Wright
Click to expand...
Bob, i recognize a rifle ammo needs good ballistic coefficient and aero - stability in order to reach out to 500 yards to do its thing. I am not trying to compare rifle and handgun of the same caliber.

My premise is that, given a high enough velocity, a lighter bullet (lighter than common handgun ammo), can effectively kill bigger than man size animals. Obviously a hand gun can not duplicate the velocity of a rifle, but what is that minimum velocity needed?

Take the 125 gr. 357mag "king of effective stopping power in handguns", it gets 1,500 ft/s out of a 4-inch barrel, per Ballistic -by-the-inch. So it would seem a 125 gr, bullet travels at 1,500 ft/s is a pretty good standard as "effective man-stopper" if i do my part putting the bullet in the right place. In fact, i see other calibers are trying to get close to that mark, e.g., 115 +P+ in 9mm and 125 gr in 357 Sig. I wonder if this holds if i do the same with 40S&W and 45ACP?

Obviously a fine working mechanical device such as handguns have tolerances on what can vary before it is not workable so one must live within that limited range of variations.

I am just trying to gain insights & wisdoms from all of you who are much more experienced shooters/ hand loaders on my take of this mass vs velocity of ammo selection. :)
 
Last edited:
Propforce said:
Thanks for the link! I did not know 50 gr 9mm existed!
Click to expand...

Sure. :cool:

Propforce said:
The article said the shorter peneteation (9.875 in) is due to the short barrel (3.5 in) test gun resulting in a 200 ft/s loss. But it showed impressive mushroom effect in the gel test!
Click to expand...

Well, that is part of it. However, the fact that the bullet lost almost half of its weight (22 grs.) by shedding those petals means that the base (28 grs.) had a lot less momentum to drive deeper into the gel block. I am not sure that I'd want to rely on such a bullet for SD, but some folks do find this sort of performance to be exactly what they want.
 
Bottlenecks do wonders. They increase velocity, but also push shoulders...meaning that they blow the cone portion of the case forward when firing under the pressure of the round FILLING the voids with case material. In a revolver this jams the case against the frame and locks the gun up. In autoloader it does good things though and it never gains much popularity. I have a .256 winmag that is awesome. On a deer it blows apart and leaves a grapefruit sized hole of nastiness and the deer typically falls within eyesight if not on the spot. Other attempts in recent times are 357 sig, 22tcm, 25naa, and 32naa. All are impressive on paper and I have no doubt they would be screamers and do well in real life, but fan - base goes conventional tapered auto case or straight wall revolver case. Kinda dumb that people won't embrace improvement, but it's debatable on whether it's improvement or not.

Also look up Lee Jurras, and his company Supervel. They did what you described years ago...but their rounds may have gone a bit too far as a lot of good guns were damaged by the ridiculous fast rounds put into guns built for slower thumpers.
 
Because handguns tend to be larger caliber. A 9mm, 38, or 357 magnum all use 35 caliber bullets weighing from 110 gr up to 200 gr. with 125 gr to 158 being the most common. A 200 gr 35 caliber rifle round would be on the light side with 225-250 being more common.

You see the same with 44 or 45 caliber handguns vs rifles. A 230-240 gr bullet is the most common in handguns of that caliber. A 44-45 caliber rifle would be using bullets weighing 250-500 gr.

o this got me thinking, what if i load a 55 gr bullet (assuming there is one that fits) on to a 9mm casing, would i be effectively increase its muzzle velocity significantly surpassing the 115 gr? Assuming conservation of KE, if i have the 115 gr 9mm exiting at 1,000 ft/s, i should be able to push a 55 gr 9mm to over 1,400 ft/s. This is in the magic velocity territory of the .357mag. Likewise if i reduce the .45 ACP from 230 gr to (omg!) 55 gr., i can increase its muzzle velocity from 890 ft/s to 1,820 ft/s!
Click to expand...

You need to also consider Ballistic Coefficients, Sectional Density and bullet construction. Bullets need to penetrate to do any good. A bullets SD, and to a point BC help to predict that. A bullet that is long in relation to it's diameter will penetrate much better all things being equal. A 55 gr 9mm bullet is going to be bigger in diameter than in length. The energy will be there, but it won't kill anything because it won't penetrate.

Within the same caliber heavier always equals longer, but when you compare bullets of different calibers all bets are off. A 124 gr bullet from a 9mm is longer in relation to it's diameter than a 230 gr bullet from a 45 ACP and will penetrate deeper assuming equal bullet construction.

Rifle bullets in the same caliber perform much better for 2 reasons. More speed, and longer, heavier bullets. Going with a bullet too light for the caliber will give you the opposite effect you are expecting even though the "MATH" looks better.
 
To me, this entire issue can be explained by the term "Cavitation". Handgun calibers make a hole roughly the same size as the bullet. High velocity rifle rounds cause severe cavitation making the size of the actual bullet somewhat irrelevant.
 
This whole thread is based on a false premise.

Of the same caliber handgun bullets are lighter and have much lower SD than rifle bullets.

30/32 caliber handguns 115g is an extremely heavy bullet

30 caliber rifle 115 is extremely light middle wight starts at 150

For 9mm/357 handgun 180g is at the far end of useful weights.

For rifles in 35 cal bullets START at 200 for the most part

Same story for 40 and 45 caliber
 
It is also based on the false premise that ANY light handgun bullet going 1,500 to 2,000 FPS will produce hydrostatic shock anything like a rifle bullet going 1,000 FPS or more faster.

The reason they don't already make main-stream very high velocity, light for caliber handgun rounds is because it has been proven over & over again over the years it works in theory, but not in practice.

The best you can hope for at reachable handgun velocity is full expansion of a hollow-point, and enough weight to drive it on through vital areas of the target.

That produces the largest wound channel, the most rapid bleeding, and the quickest incapacitation of a living target possible with a handgun.

Usually, with far less muzzle blast and flash then you would have to deal with using a 'fast & light' bullet that would not penetrate deep enough.

You are thinking up the wrong stream.

If it worked as you surmise?
We would all be shooting 2,000 FPS .22 pistols for SD and military.

But we are not.

rc
 
Last edited:
R.W.Dale said:
This whole thread is based on a false premise.

Of the same caliber handgun bullets are lighter and have much lower SD than rifle bullets.

30/32 caliber handguns 115g is an extremely heavy bullet

30 caliber rifle 115 is extremely light middle wight starts at 150

For 9mm/357 handgun 180g is at the far end of useful weights.

For rifles in 35 cal bullets START at 200 for the most part

Same story for 40 and 45 caliber
Click to expand...
Kinda. Rifle and pistol calibers are measured differently making the diameters different. Great example is that 30 cal rifles are .308 diameter and handgun 32 caliber is .311. Realistically what matters is the bullet itself and velocity it is travelling at. If handguns can reach 2000 fps and do so reliably without violent recoil, muzzle blast, or other major deterrents then they may. At that point bullets need designed to work in that velocity range, then they may be very similar to lower end rifle rounds like 30-30 or 30carbine....basically where the .327fed is. There is nothing mythical or magical about the platform launching the bullet...it's all about the factors of the bullet.
 
True that too.

But nobody could argue the .30 Carbine and 30-30 Winchester work more on adequate penetration then hydrostatic shock.

You won't get much of either with a high-speed small caliber handgun bullet.

Rc
 
Status
Not open for further replies.

Similar threads

P
  • Locked
Quantifiable Criteria for a "Woods" gun?
2 3 4 5
Replies
122
Views
13K
Vern Humphrey
V
C
  • Locked
Is a heavier bullet more "accurate"?
Replies
21
Views
4K
outofbattery
O
RA40
  • Locked
Soft recoil?
Replies
6
Views
1K
Vern Humphrey
V
K
  • Locked
Energy, Bullet Weights, & Short Barrels
Replies
11
Views
995
jfh
jfh
S
  • Locked
Why doesn't the .45 look more powerful than the 9mm on paper?
2 3 4 5
Replies
103
Views
5K
Kevin108
K
Back
Top