Question: When Does a Pistol Caliber Become a Rifle Caliber?

General Firearms Terminal Ballistic Information
1

All,

As is often said, “pistols are pistols and rifles are rifles”. But at what point does a pistol caliber become a rifle caliber?

Let’s compare four self-defense loads:

Federal LE Tactical HST JHP
9mm Luger +P
124 gr
1200 fps
396 ft-lbs
https://www.luckygunner.com/9mm-p-124-grain-jhp-federal-le-tactical-hst-1000-rounds

Federal LE Tactical HST JHP
.45 ACP
230 gr
950 fps
461 ft-lbs
https://www.luckygunner.com/45-acp-230-gr-jhp-hst-federal-law-enforcement-1000-rounds

Federal LE Tactical SP
.223 Remington
55 gr
3220 fps
1266 ft-lbs
https://www.luckygunner.com/223-rem-55-grain-soft-point-federal-le-tactical-tru-500-rounds

Federal Fusion SP
7.62x39
123 gr
2350 fps
1508 ft-lbs
https://www.luckygunner.com/7-62x39mm-123-gr-federal-fusion-20-rounds

MUZZLE ENERGY –> LETHALITY

There’s a clear difference in muzzle energy. The .223 bullet is less than half the size of the 9mm bullet, but because it’s going nearly 3x as fast, it’s going to be more lethal:


https://www.ar15.com/ammo/project/Self_Defense_Ammo_FAQ/

Is there a point at which a pistol caliber becomes a rifle caliber in terms of muzzle energy? Is there an accepted standard, e.g. “Any bullet that delivers more than 1000 foot-pounds energy is no longer a pistol caliber, but a rifle caliber”?

SPEED –> FRAGMENTATION

There’s a clear difference in feet per second. It’s been well-documented that misses from faster rifle bullets are less likely to pose a danger to others:

“Statements are made that the shotgun or pistol should be used because of the over-penetration problem with 5.56 carbine ammunition. This could not be further from the truth. If you conduct a little research you will find that numerous law enforcement departments, to include the FBI, have proven this to be false in most cases. The fact of the matter is that many of these bullets will penetrate numerous walls, but standard 5.56 loadings are the least of your worries when compared to pistol and shotgun fodder, which continue to take top honors in the category of over-penetration.” US Army Sergeant Major Lamb (former Delta/CAG)
https://www.americanrifleman.org/articles/2015/5/26/the-ar-for-home-defense-one-experts-opinion

“Common pistol rounds easily penetrated all 4 walls spaced out at room distances. This is a critical issue. Think about the inside of your house and imagine if you shot through 4 walls. Could you hit a loved one? Know your target and what is behind it…The 5.56 rounds deviated greatly from the original flight path once they started tumbling. This occurred after the second wall.” Old_Painless (certified Pistol, Rifle, Shotgun, Personal Firearms Defense, and Home Firearms Safety Instructor)
http://www.theboxotruth.com/the-box-o-truth-12-insulated-walls/

“Proponents of the pistol for home defense like to think that because it’s ‘just’ a pistol round, overpenetration really won’t be an issue. Such is not the case. Drywall sheets and hollow-core doors (which are what you’ll find in the majority of homes and apartments in this country) offer almost no resistance to bullets…For years many people just assumed they knew what would happen to a rifle bullet fired indoors—it would go through every wall available and then exit the building. While armor-piercing and FMJ ammunition is specifically designed to do this, extensive testing has shown that light, extremely fast-moving .223 projectiles (including FMJs) often fragment when they hit a barrier as soft as thin plywood.” James Tarr (former police officer; contributing editor for Guns and Ammo)
http://www.gunsandammo.com/ammo/long-guns-short-yardage-is-223-the-best-home-defense-caliber/

“The .223/5.56 is moving at around 3,000 feet per second, and while it isn’t magic bullet, it’s a far cry better than any pistol round. Another advantage of the .223/5.56 is its limited penetration. The shape and velocity of the round cause it to immediately expend or dissipate its energy once it strikes something.” Tiger McKee (adjunct instructor at Thunder Ranch)
https://gundigest.com/reviews/ar-15-ideal-home-defense-guns

“The pistol rounds were seemingly unaffected by the drywall and/or wood barriers. There was no observable deviation or fragmentation of the 9mm projectiles. You’d be safe counting on a pistol round to keep going, and going, and going. After all, premium pistol ammunition is designed to expand, and lose energy, when striking liquid-based targets—not walls. The full metal jacket .223 rounds tended to tumble rather than break apart when they encountered barriers.” Tom McHale (contributor at AmmoLand and OutdoorHub)
http://www.outdoorhub.com/stories/2013/11/04/ar-15-appropriate-home-defense-part-one-penetration-issues/

“FBI and Independent Testing Has Consistently Shown .223/5.56 NATO Fired From AR-15’s Do Not Over Penetrate More Than Pistol/Shotgun.” Caleb Lee (NRA Certified Basic Pistol & Personal Protection Inside The Home Instructor)
http://preparedgunowners.com/2016/07/14/why-high-powered-5-56-nato-223-ar-15-ammo-is-safer-for-home-defense-fbi-overpenetration-testing/

“Since all of the 5.56 mm/.223 bullets fired through the interior wall had significantly less penetration than 9 mm, .40 S&W, .45 ACP, and 12 ga. shotgun projectiles which were fired through an interior wall, stray 5.56 mm/.223 bullets seem to offer a reduced risk of injuring innocent bystanders and an inherent reduced risk of civil litigation in situations where bullets miss their intended target and enter or exit structures. As such, 5.56mm/.223 caliber weapons may be safer to use in CQB situations and crowded urban environments than service caliber handguns or 12 ga. weapons.” Dr. Gary Williams (ballistics expert)
http://www.recoilweb.com/ar-vs-shotgun-for-home-defense-again-2-of-2-39203.html#ixzz4zCOCPykZ

Those who subscribe to this principle believe that if you’re concerned about overpenetration, the faster (and smaller) .223 is better for home defense than the slower (and bigger) 7.62x39 (and of course, better than even slower [and even bigger] pistol rounds).

Is there a point at which a pistol caliber starts to behave like a rifle caliber in terms of speed? Is there an accepted standard, e.g. “Any bullet that travels more than 2000 feet per second is no longer a pistol caliber, but a rifle caliber”?

Respectfully,
butlers

2

Is there a point at which a pistol caliber starts to behave like a rifle caliber in terms of speed?

It’s a sliding scale for sure but the stretch cavity that rifles produce, as opposed to pistol round, generally occurs around the 1,900-2,200 FPS range

3

This. Shotgun slugs make rifle-ish temp cavities around 1800fps because of the large surface area and mass.
As projectiles get smaller, the velocity has to increase.
.224-.30 is around 2000fps or so.

4

Bingo! It’s not as simple as upping velocity = rifle-like terminal ballistics. The SHAPE of the projectile matters alot. Take a look at 19th century lever gun ballistics, cartridges like the .45-70 in historical bullet weights are almost always traveling below the magic 1900-1800 fps and produce rifle like temporary stretch cavities. Now shoot a .30 cal steel BB at 4000 fps into gel and you almost no temporary stretch cavity.

5

Yes. Upset is a huge factor. Iirc Doc said they pushed .22” projectiles around 7,000fps and they made pin-holes because there was no upset. Each bullet has its own behavior, the mass/diameter/velocity gives it good potential.

6

His test methodology must have been off.

a .22 at 7,000 fps is a miniature nuke.

7

No thats 10mm. Here is the scientific proof.

8

No his methodology was sound, they were testing extreme velocities with rounds designed to not upset iirc.
… but please do continue about how DocGKR is not properly performing terminal ballistics testing.

9

Save your sanity and dont bother arguing with people so far out of touch with reality. It isnt worth it.

10

Thank you all for your input.

I enjoy introducing firearms to new shooters, and I run an informal class on the differences between pistols, rifles, and shotguns. With the advent of atypically high-velocity pistol rounds and atypically low-velocity rifle rounds, I’m having a difficult time distinguishing between the two.

For example, let’s say you’re a range master at an indoor pistol range.

  • One shooter comes in with his 10.5" suppressed 300 BLK SBR.
  • The other shooter comes in with his 16.0" 10mm pistol caliber carbine.
  • The first guy shoots a Hornady “A-MAX” 300 BLK bullet – it’s 208gr traveling at 915 fps (out of a 10.5" barrel) = 387 ft-lbs muzzle energy.***
  • The second guy shoots a Liberty “Civil Defense” 10mm bullet – it’s 60gr traveling at ~2793 fps (out of a 16.0" barrel) = 1039 ft-lbs muzzle energy.###

You’re the range master. Do you stop the first guy, the second guy, both, or neither? How do you justify/articulate your judgement call? Do you cite bullet weight? Velocity? Muzzle energy? Shape (i.e. spitzer vs non-spitzer)? Remember, one is shooting 300 BLK (originally designed as a rifle round) out of a short barreled rifle (but it’s performing like a pistol); the other is shooting 10mm (originally designed as a pistol round) out of a pistol caliber carbine (but it’s performing like a rifle).

Things that make you go “hmmm…”

//youtu.be/XF2ayWcJfxo

P.S. My math:

***These figures are from this test:
https://www.shootingtimes.com/editorial/ultimate-300-aac-blackout-ammo-test/99395

###These figures are estimated from this data:
http://10mm-firearms.com/factory-10mm-ammo/liberty-civil-defense-60gr-2400-fps/
http://ballisticsbytheinch.com/10mm.html

10mm 60gr tests

  • 4.75" barrel = 2511.5 fps
  • 6.00" barrel = 2596.0 fps
  • thus, 1.25" barrel difference —> 84.5 fps difference = average 67.6 fps increase per 1" barrel

10mm 135gr tests

  • 6.00" barrel = 1504.0 fps
  • 8.00" barrel = 1575.0 fps
  • 10.00" barrel = 1601.0 fps
  • 12.00" barrel = 1653.0 fps
  • 14.00" barrel = 1691.0 fps
  • 16.00" barrel = 1701.0 fps
  • thus, 10.00" barrel difference —> 197.0 fps difference = average 19.7 fps increase per 1" barrel

We know that the 10mm 60gr out of a 6.00" barrel gets us to 2596.0 fps. So let’s be very conservative and say that adding 10" barrel will only get us an additional 197.0 fps difference. So, we estimate that the 10mm 60gr out of a 16.00" barrel = 2793 fps.

11

The users of these two weapons aren’t likely to care about bullet weights and muzzle velocities.

A 300 Blackout SBR is a rifle firing a rifle cartridge. If rifle calibers are allowed at the range, then they’re fine. If they’re not allowed, then this rifle isn’t allowed.

A 10mm Auto carbine is firing a pistol cartridge. If pistol caliber carbines are allowed at the range, then they’re fine. If they aren’t allowed, then the rifle isn’t allowed.

The easy answer is that if a cartridge was initially developed for use in a handgun, then it’s a pistol caliber. If the cartridge was initially developed for use in a rifle or carbine, then it’s a rifle caliber. There’s little to benefit by making this more complicated than it needs to be.

12

So if you were serving as the range master at a pistol caliber-only range, and you had one shooter firing a 208gr 300 BLK projectile traveling at 915 fps (387 ft-lbs muzzle energy) and you had another firing a 60gr 10mm projectile traveling at ~2793 fps (1039 ft-lbs muzzle energy), you would kick the first guy off the range because he was firing a cartridge “initially developed for use in a rifle” but you’d be OK with the second because he was firing a cartridge “initially developed for use in a handgun”?

13

Yes.

Does the guy shooting the 300 Blackout have a chronograph with him to show that his ammo really is travelling at that velocity? Is he going to disassemble all his ammo to show that it’s loaded with the same bullets and amount of the same powder as the round that he chrono’d for you?

14

That’s a fair point. I was talking in the abstract (i.e. how do I explain pistols vs. rifles to non-shooters?), but you’re right: it’s difficult to enforce such categorical distinctions in the real world.

15

How would you know they were shooting 60gr projectiles out of their 10mm carbine? Thats such an uncommon bullet weight how often would you really see that in the real world. There are exceptions to everything. What if some guy started shooting 7.62 SLAP out of his .308 at your steel targets? I mean how uncommon do you want to go here?

16

OK, I think we’re getting off topic (my fault).

My hypothetical was designed to show the limitations of traditional definitions. When 300 BLK rifles shoot larger bullets going relatively slowly (like pistols) and 10mm pistols shoot small bullets going very fast (like rifles), the line between the two gets blurred.

So for someone who tries to educate his non-shooting friends on the subject, my original questions still stand: is there a commonly accepted muzzle energy cutoff that defines rifle vs. pistol? Or is there a minimum fps standard? The answer thus far seems to be “no” to both.

17

As was mentioned in a previous post, the change to “rifle-like” performance for .30 caliber projectiles is 1900fps or so. A number of years ago I asked and Doc said that the M1 Carbine did, in fact, cause “rifle-like wounds”. I did not think to ask at what distance it lost this property. He also said that a .44Mag shot from a lever-action carbine causes rifle-like wounds.

My understanding is that it is the size of the temporary cavity that makes the difference, so the effective frontal area and the velocity both enter into the equation. Damage is done if the tissue is stretched too far. I used the term “effective frontal area” because if a fmj or solid bullet yaws 90 degrees, it is traveling side-on to the tissue, so the “effective frontal area” is the side profile of the bullet. This adds the complication that for a particular caliber, a long, round-nosed fmj bullet that doesn’t yaw will produce less damage than one that does yaw.

18

Really simple: Rifle ammo comes in 20 round boxes while pistol ammo comes in 50 round boxes. Last time I was at the range two guys where trying to pour every ounce of knowledge on a new female shooter… she left early… Remember KISS with new shooters.

19

I found a quote from DocGKR in a 2011 post:
“.44 Mag is a caliber that is in the transitional range between service caliber handgun loads with minimal stretch effects and rifle calibers with substantial TC damage, as in some cases .44 Mag generates a sufficiently large temporary cavity to damage susceptible inelastic tissues. Hopefully you have read: https://www.m4carbine.net/showthread.php?t=19930. As noted, my .44 Mag general purpose load of choice is the Hornady 300 gr XTP. Another transitional caliber where TC is beginning to be a significant mechanism of wounding is the .30 Carbine when using good quality expanding ammunition like the Barnes 110 gr XPB, Rem 110 gr JSP, and Speer 110 gr Gold Dot.”

20

9x25 Dillon gets 2000-2200fps with 80-90gr bullets from 5-6in barrels: https://www.underwoodammo.com/collections/handgun-ammo/products/9x25mm-dillon-90-grain-xtreme-defender?variant=18785701691449 & http://www.doubletapammo.net/index.php?route=product/product&path=303_372&product_id=626. If you reload you can push them faster. And you can use the Lehigh Xtreme Defender 65gr bullet to go faster still, over 2500fps from a 6in barrel.

You can convert a Glock G29 to 9x25 with just a barrel swap (or any 10mm pistol really, the G29 and G20 just have the cheapest barrels). Very easy to CCW a pistol that would have true “rifle” wounding with the right loads in 9x25 Dillon (and less recoil than 10mm too). I think this is a pretty big jump in terminal performance for pistols with a pretty low relative overall cost involved.