A cutaway 12-ga. pump shotgun – see how it works

While most of us who’ve hunted are familiar with a pump shotgun, not many (myself included) have ever seen the innards of the gun or know much about exactly what goes on when the slide is racked. I stumbled onto this video and really enjoyed seeing, on a cutaway gun, precisely what happens when it’s pumped. The presenter, gunsmith Hunter Roosevelt, actually cuts away parts of a Winchester Model 12 pump and proceeds to walk the viewer through what’s going on when the slide is racked.

The one really sore point that comes to mind whenever I read or see the term “pump shotgun” is the iconic sound that racking the slide makes. If a pump shotgun appears in a movie (and they’re everywhere in action movies), you can bet your bottom dollar that you’ll hear that iconic sound. The problem is, in most cases, the shotgun was probably carried at the ready or even pointed at someone as if ready to shoot – but then the slide is racked. And since no round was ejected, that points out that the gun was empty before racking the slide. So, our hero (or villain) was parading around making threatening or menacing moves, all the while sporting a shotgun with an empty chamber – hardly a smart move. But no matter, it’s all for effect anyway. Gotta hear that dreaded “CHK-CHK” sound to show that someone is in deep trouble.

Mr. Roosevelt gives us a brief history of the Model 12 and then proceeds to disassemble it before milling away metal to yield a cutaway of a real, honest-to-goodness, pump shotgun. ENJOY!


And here’s a final bit of interest. All gun nuts eventually learn what specifications refer to when discussing pistol or rifle ammunition (calibers, millimeters, grains, etc.), but how many of us know where the “gauge” measurement used for shotguns came from? I didn’t.

Gauge is determined from the weight of a solid sphere of lead that will fit the bore of the firearm and is expressed as a fraction of a pound. Thus, a 12 gauge identifies a bore that is designed to fire a ball that weighs 1/12 of a pound. And this was derived from the measurement of cannon, which were also measured by the weight of their iron round shot; an 8 pounder would fire an 8 lb. spherical cast iron ball.

Like the old saying goes, we learn something new every day. I hope that this little post was your “something new” for today, I know it was for me.



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7 Responses to A cutaway 12-ga. pump shotgun – see how it works

  1. captbogus2 says:

    Okay so I am still confused by the .41 0 shotgun.
    I was told it was the caliber but then the .410 shoots the .45 Long Colt.
    Can you clarify this point?

    • Garnet92 says:

      Sorry capt., I plumb forgot about the .410. Actually, the .410 isn’t a gauge at all, it’s the diameter of the bore – .410 inches. If it were described as a gauge, it would be a 67-68 gauge. As far as the .45 Colt goes, a handgun chambered for the .45 Colt will accept a .410 shot shell although the shot shell is much longer. There are a few, Thompson Contender, for example that can shoot either.

  2. Uriel says:

    Thanks Garnet. I am gun dummy so it helps.

    • Garnet92 says:

      You’re not alone Uriel. As I said, I didn’t know exactly what constituted a “gauge” either. I thought that the little bit of information on why shotguns were identified as being of a certain gauge and how that was determined would be of interest to our readers. And I learned too.

      That’s something that I learned a long time ago. In my business, I did a lot of training and in doing preparation for a new class or a white paper, I found that I learned a lot, just as a byproduct of verifying that what I wrote or taught was true and accurate.

  3. 219rad says:

    Thanks Garnet – That video will keep me from slicing and dicing my Remington 870 magnum 12 gauge. I also didn’t know how they came by the gauge measurement.

    I think I look much smarter now.

  4. Hardnox says:

    Interesting! I learned about the gauge thing long ago after visiting the NRA National Firearms Museum way back when it was located in DC on Rhode Island Ave.. Haven’t been to the new one yet now located in Fairfax Virginia. I understand it is spectacular. It’s on my bucket list.