Different Ammo in the Same Gun…Kaboom?

Your revolver is a .357 magnum, but people say it shoots .38 special.

Your new AR-15 says it can shoot 5.56x45mm NATO, but your friends say just pick up a box of .223.

What’s going on here?  

Has the world turned upside down?  Don’t they realize that we’re dealing with BULLETS here?

Freedom Seeds

Have a cup of tea. Let’s talk. It’s possible that a firearm chambered for one round can safely fire another.  There could be any number of reasons for this.  Some guns, like the Taurus Judge, are designed to do that, and with some, it’s just a happy coincidence.

Common Examples

The best example of this is the .357 magnum revolver.  You see, back in the long-long-ago, the 1930s, police officers were issued .38 special revolvers as their sidearms.  About this time, bullet-proof vests were just coming into being and gangsters were using their car doors as cover during shoot-outs.

Speed Loader and Tuff Strip
Speed Loader for 5-shot .38 on left; Tuff Strip for .357 Mag on right

Well, .38 special couldn’t pierce body armor and it wouldn’t go through car doors, so police departments looked for a solution.  Smith & Wesson provided one in a new round that used a standard .38 special bullet but with a lot more power behind it.  It was dubbed the .357 magnum.

Editor's Choice
729
at Brownells

Prices accurate at time of writing

Prices accurate at time of writing

The bullets have the same diameter, but the .357 could punch through the new body armor that was showing up on the streets.

As mentioned, the .357 magnum has a lot more power, which means more pressure.  Regular .38 special revolvers couldn’t handle the pressure, which meant that .357 magnum revolvers made specifically to handle the load had to be developed.

As an added safety precaution the length of the .357 magnum case was extended by 1/8 of an inch.  This way, a person couldn’t load and close a .38 special revolver with .357 magnum ammunition and accidentally blow themselves up.

But because the diameter of both bullets are the same and the pressure in a .38 special is less than that of a .357 magnum, a .38 special round can be safely fired in a .357 magnum revolver or lever gun.

So to sum up in one sentence: You can shoot .38 special in .357 magnum guns, but you can’t shoot .357 magnum in .38 special guns.  Got it? If you want to learn more and get some great ammo recommendations, read our Best .38 Spl & .357 Mag Ammo article.

Under Pressure

Pressure is the big determining factor because a firearm rated for one kind of ammunition may have features beyond safety designed specifically for that round.

For instance, according to Patrick Sweeney at Rifle Shooter Magazine, the 5.56x45mm and the .223 look the same, but the 5.56 is loaded for a higher pressure to increase velocity.

Chambers that are designed specifically for .223 have a narrower leade (the unrifled portion of the chamber ahead of the rifling) and a steeper angle of rifling.  This is because the .223 was designed primarily for accuracy.

The 5.56 was designed to deliver more power and reliability, so the leade is wider and longer to allow more build-up of crud and a more gentle angle of rifling to accommodate the power of the 5.56.

Common Bullet Sizes
Common Bullet Sizes

Sweeney said the end result is that you can safely fire a .223 in a 5.56 chamber, but there are risks when firing a 5.56 in a .223 chamber.  He also recommends that even if your AR15 says 5.56 and .223, you should check it for yourself with a leade/throat gauge.

Some manufacturers use .223 barrels because they’re more accurate but they stamp their rifles as 5.56 and .223. Personally, I’ve never seen/heard of this happening nor have I have ever double-checked a barrel that came from a respectable manufacturer.

What about .308 and 7.62x51mm?

There’s a similar issue between .308 Winchester and 7.62X51mm.  The .308 is a hotter load and the headspace is different from that of the 7.62.  So while they look identical and people will say you can use them interchangeably, they’re different rounds.

Generally speaking, you can safely shoot 7.62mm in a .308 rifle, but you’re taking a risk going in the other direction.

These three examples aren’t the only ones out there.

Like with the .357 magnum example above, you can shoot .44 Special (I bet you didn’t even know there was a .44 Special, huh?  Learn something new every day) in a .44 Magnum, but not the other way around.

Taurus straight up advertises that you can shoot a .45 Long Colt or a .410 shotgun shell in their Taurus Judge.  It’s just a matter of knowing what you can fire from your weapon safely.

Old M1895 Nagant revolvers can supposedly shoot .32S&W, .32S&W Long and .32H&R Magnum rounds, but it’s not safe, and I’m telling you right now you shouldn’t do it.

Mosin Nagant Revolver
Mosin Nagant revovler…widely thought to be the worst revolver ever adopted by a military force

Like a lot of things with firearms, it all comes down to safety.  When in doubt, use the ammunition that’s stamped on the firearm.  But it’s nice to know that there are other options out there.

Want to learn more about calibers and bullet types?  Check out our Common Calibers Guide.

Know of some other firearms that can shoot two different cartridges? Tell us about them in the comments! Any other questions…we cover almost everything in our Beginner’s Guide to Guns.

14 Leave a Reply

  • Peter Marygold

    Can anyone tell me if you can fire a.32 caliber bullet in a .38 hand gun?

    4 months ago
  • Chris

    Anyone know about the .17 caliber rifles ... is there any new product/rifle out that can shoot centerfire variations of the 17 caliber ..... Is there any high-capacity bullet rifles of this caliber ... I’m very interested in this caliber and I’m interested in buying a rifle I want to get one that says versatile I’d appreciate any information thank you . [email protected]

    9 months ago
  • Heimlich gero

    Can a shotgun have two different bullets that can switch in the same barrell

    1 year ago
    • Eric Hung

      Hi, if I'm understanding correctly, shotguns can have a variety of different shells if they are the correct gauge and length. Eg...one buckshot, then one birdshot, then one slug, etc.

      1 year ago
  • M tactical

    We can shot a ak 47 bullets from scar heavy or any other 7.62 weapons

    2 years ago
    • Eric Hung

      AK47 rounds are 7.62x39 while the SCARH and other "7.62" guns are 7.62x51mm.

      2 years ago
  • Dennied

    Doing research for genealogy, I came across a 1928 murder/suicide. Long story involving a bigamist and a couple of her "husbands". The death reports say that only one gun was used but the shooter was shot with a 32 cal bullet and the other husband was killed with a 38 cal. I haven't been able to find out anything about the woman. The shooter was a WWI Marine veteran. I haven't found anything on the model gun, other than one newspaper referred to it as a pistol.. So do you think a 1928 pistol could shoot 32 and 38 cal bullets?

    2 years ago
  • Kevin

    Thank you for the info. I inherited some 7.62X51mm rounds and needed to know if I could use them in my .308 Winchester rifle.

    2 years ago
    • Eric Hung

      Normally you can do that but I would ask Winchester with the specific ammo to be safe.

      2 years ago
  • Darkman

    Hey Marcus. I checked with bushmaster as I purchased An XM-15 E S in 2016. Yes it will shoot 5.56. I've shot Barnes 5.56x45 69 and 85 grain OTM BT with no issues.

    2 years ago
  • Marcus T.

    I have a XM15 Bushmaster that says 5.56 .223. Can any gunsmith check the leade/throat for me, what numbers am I looking for. Are there other round that I could use for my 30-06 and 30-30. The "Basic Bullet Guide: Sizes, Calibers, and Types" was very helpful for me.

    2 years ago
  • Adam Seker

    Good article, but the .460 wasn't mentioned. If memory serves; the .460 S&W can also safely fire a .454 Casull and .45 LC. Just thought I'd throw that little addition on the end.

    2 years ago
    • Bruce Berry

      You can not shoot the 460 out of the 454 I have a 454 and 45 the ragging judge pistol that shoots 45 lc and 454 casull and 410 3 inch out of the same cylinder I bought it last year at guns and ammo 800 dollars new I collect guns .460 is bigger just like the 45 a 44 mag will fit in a 45 but the 45 will not fit the 45 I have done proved that .

      1 year ago
    • Eric Hung

      Hey Adam, that's great info!

      2 years ago
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