Why isn't a 3" shell 3" long?

[PWF3]

Ok, I am obviously new at this but I just ordered a Mossberg 20ga with 18.5" barrel for home defense, my first shotgun. And I was noticing that the Winchester shells say 2 3/4" but they aren't even close to that long. So, the question is: what makes a 3 inch shell, 3 inches long?

 

[funkybassplayer]

hmmmmm...now i myself am curious.

 

[juwaba98]

I'll have to double check, but I believe the measurement is of the expended shell. Meaning after it has opened up and discharged its shot. Open they should be 2 3/4" or 3" depending on the variety. If you are thinking of it in terms of chamber size, consider the difference in a shotgun shell and a rifle cartridge. The rifle merely has to accomodate the case as the projectile is inserted into the beginning of the barrel and expended from there when fired. With a shotgun it is quite different in that the shell is crimped closed and must open within the chamber to send all that lead out the barrel. I still don't think they are exactly 2 3/4" or 3" after fired but unless things have changed that is the reason for it.

Hope this helps some.

 

[Bullseye Shooter]

I'll have to double check, but I believe the measurement is of the expended shell.

Correct. 3" is the chamber measurement, not the shell itself. Once it's fired, it fits the chamber exactly. That's why it's a bad idea to shoot 2 3/4" 16 gauge shells in a 2 9/16 chamber; not that you see too many 2 9/16 chambered guns anymore, but I suppose they are around.

 

[funkybassplayer]

Correct. 3" is the chamber measurement, not the shell itself. Once it's fired, it fits the chamber exactly. That's why it's a bad idea to shoot 2 3/4" 16 gauge shells in a 2 9/16 chamber; not that you see too many 2 9/16 chambered guns anymore, but I suppose they are around.

My dad has two old 16 gauges and we were discussing heading out to the skeet range soon. how can i check the chamber size so i don't run into the 2 3/4" shells VS 2 9/16" chamber issue?

 

[Bullseye Shooter]

Mfg usually mark the barrels with the shell length. I know my old Winchester Model 12 was marked 2 3/4".
If the barrels aren't marked, just break the gun down so you can run a tape measure inside the chamber and measure it from the back edge to the lip on the front of the chamber where the shell would expand to when you shoot it. Make sense?
If you run in to a problem, send me a PM and we'll figure it out. What kind of shotguns are we talking about and when were they made? Most mfg stopped making 2 9/16 guns before WW II.

 

[funkybassplayer]

before WWII?!?! prolly won't be a problem then. I believe they are remingtons (one pump, the other semi-auto) that my dad and his brother hunted with growing up about 60 years ago. i need to look and get the models and serials so i can nail down the age.

 

[Bullseye Shooter]

If they're Model 870s, they are more than likely 2 3/4 inch. They will be marked on the barrel, left side, near the receiver.

 

[Texas1911]

My dad has two old 16 gauges and we were discussing heading out to the skeet range soon. how can i check the chamber size so i don't run into the 2 3/4" shells VS 2 9/16" chamber issue?

Depending on how old they are you might want to watch what ammo you feed them. Some of the older shotguns don't cope with modern ammo very well (pressure).

 

[Bullseye Shooter]

Depending on how old they are you might want to watch what ammo you feed them. Some of the older shotguns don't cope with modern ammo very well (pressure).

He indicated they were in the 60 year old range which puts them being produced right after WW II. A Remington from that time frame should handle skeet loads (or any other load) okay. Shotgun pressures are not that dramatic compared to rifle or pistol loads.

I would be worried if we were talking about some Damascus barreled antique from before 1900 but even Winchester Model 12s from the first production run on, have been able to handle modern smokeless shotgun ammunition. The only disclaimer would be shooting steel shot out of some older guns since the barrels were not designed for steel shot.

If we're talking Remington 870s, they have one of the strongest actions out there.

 

[funkybassplayer]

well i say it was 60 years ago becasue my dad and his brother are both late 60's early 70's. I am going to try and get the bnumbers off the guns to see how old they are.