Shell size ?

[BigMuddy]

I have a 20 gauge single shot shotgun that is chambered in 2 3/4”. I was recently given a boat load of 20 gauge 2 7/8” shells. I have searched the web and can’t find anything telling me yes or no in regards to shooting these shells out of my gun. I called a gun store I shop at and I was told “you should be ok”. Should be……. Not sure I want to drop the hammer on a SHOULD BE. The gun will accept the bigger shell and the breach closes fine. Any suggestions from my INGO family ?

 

[hoosierdaddy1976]

I have never heard of a 2 7/8 in shell, though shell length is closer to the length of a fired shell. Are they marked 2 7/8 or is that what they measure?

 

[Mgderf]

Could be nothing more than the difference between measuring devices.
1/8" is not out of the question.
I've seen poor quality tape measures be off by more than 1/4".
At 2-7/8", I would consider it a 3" shell, and your answer is no, do not shoot them from your 2-3/4" chamber.

 

[DoggyDaddy]

I can't remember the brand right now, but I picked up some 20 gauge shells that didn't have the usual "star" crimp, but instead had a "roll" crimp with a cardboard disk to hold the shot inside. I tried loading my 20 gauge pump (normally a 5 round magazine, but I couldn't get the 5th shell in there because being crimped like that they were actually slightly longer than the advertised 2 3/4" length. I contacted the vendor and they confirmed that this was the case. After firing, they're the same length as shells with the standard crimp.

OP, what is the crimp like on your shells?

 

[Mgderf]

I can't remember the brand right now, but I picked up some 20 gauge shells that didn't have the usual "star" crimp, but instead had a "roll" crimp with a cardboard disk to hold the shot inside. I tried loading my 20 gauge pump (normally a 5 round magazine, but I couldn't get the 5th shell in there because being crimped like that they were actually slightly longer than the advertised 2 3/4" length. I contacted the vendor and they confirmed that this was the case. After firing, they're the same length as shells with the standard crimp.

OP, what is the crimp like on your shells?

Roll crimp vs star crimp will make a difference.
The problem arises when the plastic case actually intrudes into the chamber, making it smaller, and constricting the shot at the breech.
If shooting soft lead shot, you might get away with it.
Hard steel, tungsten, or slugs may go boom, but not the way you want.

 

[drm-hp]

Shotgun shells are measured fully open, not when crimped shut.
I will not be telling you whether or not it is propper to shoot a too long case cartridge but short is normally entirely propper if shooting shot.
20 gauge, 3" chamber: 2 3/4" and 3".
16 gauge, 2 3/4" chamber: 2 9/16" and 2 3/4".
12 gauge, 3.5" chamber: 2", 2 1/2", 2 3/4", 3", and 3 1/2".
There are many other instances but these are some of the more common examples.

 

[Leo]

DRM-hp is right a shell shorter than the chamber is no problem, a shell longer than the chamber IS a big problem.

A 2-3/4 shell will measure shorter than that when loaded. More like 2-1/2, but it is 2-3/4 when the it is opened by the pressure when shot.

DO NOT try to fire a 3 inch shell, even if you can make it fit. A loaded 3 inch shell MAY be finish length of close to 2-3/4 when over crimped, but you will have a sudden very high pressure when fired because the opened shell has no void to allow it to open, acting like a plugged up barrel.

Since Shotshells all headspace on the rim, Over all length when fully (or over ) crimped does not matter in the chamber. What does matter is that the larger diameter in the chamber has plenty of room to allow the hull to fully open, before the wad and lead shot finds its way down the smaller diameter of the barrel.

 

[Frosty]

I measured a few of my shells, all a variety of birdshot and they all measured 2 5/16” on a ruler.