To amplify what was contained in the "Caliber Confusion" article.  It is very important that the individual shooter know EXACTLY what caliber is pistol, rifle, or shotgun is designed to shoot.  Bad (and sometimes fatal) consequence can result from using the wrong ammunition in the wrong firearm.

 

Some common screw-ups:

 

1.  Do not use sabot-type shotgun slugs in shotguns with screw-in or with chokes machined into the barrel.  The plastic sleeve around the sabot that's designed to take the rifling of a rifled shotgun barrel or rifled screw-in choke, does NOT compress when it hits the choke restriction in the bore.  The gun will blow-up.  If you are lucky, all you'll have to show for it is a banana-peel of a barrel.  If you're not, it's the hospital or morgue.  (Note: you can shoot the lead Foster-type slugs designed for smooth bore barrels through choke tubes.  The slug is hollow in will be sized by its passage though the choke.  The problem is, the now undesize round is not accurate.)

2.  The 12/20 guage screw-up related to carrying both kinds of ammo to the field.  Problem: the 20 gauge will drop into a 12 guage barrel far enough for a 12 gauge round to follow.  When you shoot the 12 gauge, it fires into the back of the 12 gauge obstruction and you will wear the barrel.  If lucky you'll probably only loose the sight in an eye or some fingers.

3.  The spire point ammunition screw-up in tube feed rifles.  Tube feed center fire rifles, such as the Marlin and Winchester are designed to use round nose soft point ammuntion.  That's because the nose of the round rests against the primer of the one in front of it.  If you reload a .30-30 cartridge with a more efficient spire point bullet for a .30-30 Model 99 Savage (the Savage has a box magazine) this round, if used in a tube feed rifle, will act as a firing pin for the primer on the round ahead of it.  The magazine tube will blow-up with unfortunate results.

4.  Rifle and pistol caliber screw-ups.

The Europeans have a very straight-forward system for designating calibers: (1) the bullet diameter in millimeters, (2) the case length in millimeters, and (3) any special caracteristic of the case -- rimless (none), belted (B), semi-rimmless (SR), rebated rimless (RB).  American and British Commonwealth ammunition is a mish-mash of black powder designations (such as the .45-70-405; .45 caliber, 70 grains black powder, 405 grain bullet); commercial designations such as .45 Government or .30-06 Springfield; or military designations of commercial cartridges 7.62x51 NATO (.308 Winchester) or .30 Government (.30-40 Krag-Jorgensen).  When you get into calibers such as these, you must know what you are doing.  If you don't, find someone who does.  Commercial rifles, shotguns, and pistols are prominently stamped with

 

Common designations for various European Military/Commercial - American Commercial - American Military caliber (does not mean adopted).

 

7.92x57 JS (.323 bullet)                          8mm Mauser                            8mm Mauser

7.62x39                                                  7.62 Russian Short                   7.62x39 Russian

7.62x54R                                               7.62 Russian Rifle                     7.62x54R Russian

7.62x63                                                 .30-06 Springfield                     .30 Caliber

7.62x33                                                 .30 Carbine                               .30 Caliber (carbine)

5.56x45 NATO                                     .223 Remington                         5.56 NATO

5.45x39                                                 N/A                                          5.45x39 Russian

N/A                                                       6.8 Remington SPC                  6.8x43 SPC (test only)

7.62x51 NATO                                     .308 Winchester                       7.62x51 NATO

7.62x25                                                 .30 Mauser (pistol)                   7.62x25

In last sentence of last paragraph change as follows:

 

"Commercial rifles, shotguns, and pistols are prominently stamped with the caliber of the firearm.  Military rifles or antique firearms may or may not be so stamped.  It is imperative that you know without a doubt what kind of ammunition your particular firearm is designed to shoot."