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Shell lengths: what difference does it make?

Posted: Thu Jan 17, 2019 10:02 pm
by polymath
Shotgun noob question: what's the deal with 2 3/4", 3", 3 1/2" shells? I've had a 3" chambered shotgun for a while and never gave much thought to whether I was feeding it 2 3/4" or 3", but as the collection grows it occurred to me that maybe it mattered.

Does it harm the gun to use shorter shells than the chamber length? Or does it affect the pattern, or is correlated with power or total weight of projectiles or ...?

Re: Shell lengths: what difference does it make?

Posted: Fri Jan 18, 2019 2:38 am
by Bang
Chamber length on your gun is the length of the chamber. Shell length on a shell is the length of the fired, uncrimped shell. Shorter is fine, longer and you're asking for a jam at the very least, but could potentially damage your gun.
Generally, just use what the manual that came with your gun says to use.

Re: Shell lengths: what difference does it make?

Posted: Fri Jan 18, 2019 8:19 am
by polymath
Good to know. In my case, the manual says nothing on the topic.

Re: Shell lengths: what difference does it make?

Posted: Fri Jan 18, 2019 3:15 pm
by spara
chamber length is often stamped on the barrel

Re: Shell lengths: what difference does it make?

Posted: Fri Jan 18, 2019 6:10 pm
by shinzen
The 2 3/4" loads are typically lighter loads, maxing out at 1 1/8oz, and will go bang in most shotguns, but may give you cycling issues if you're running the lighter 1oz load in a semi that is designed for heavier loads. 3" shells are pretty standard these days, going from 1oz (which again, may give you cycling problems) up to 1 7/8 oz if you like to torture yourself or are hunting turkeys, and most newer shotguns will run them with no issues.

The 3 1/2" shells are heavy loads- people use them commonly for turkey, running up to 2oz of shot. Also the most expensive, even in the lighter loads.

For most clay busting? Just get some cheap 2 3/4 ammo at 1 1/8 oz. I picked the Stoeger M3000 over the M3500, as I couldn't see the utility in being able to handle the larger shells. In an over/under, definitely no real need to worry about the 3" stuff unless you have a specific purpose in mind.

Of course, that's from my still barely more than a beginner mindset on shotguns. I'm happy if I can hit 21 out of 25, and it's usually 18 or 19 instead. Shouldn't cause an issue. Obviously you DON'T want to try to cram a 3" shell into a 2 3/4" chamber- that's a terrible idea. But shorter is okay.

Re: Shell lengths: what difference does it make?

Posted: Sun Jan 20, 2019 7:33 am
by NuJudge
Look in the rear end of your 2.75" 12 gauge chamber. You will see a gradual constriction a bit under 3" from the rear of the chamber, called the forcing cone. Until fairly recently, the typical 12 gauge shotgun had that constriction only 2.75" ahead of the rear of the barrel. A unfired 3" 12 gauge shell will fit in a 2.75" chamber. If the fired case on your shell extends into that forcing cone, you will have a pressure spike.

The volume of shells sold makes a huge difference in price. This is why 12 gauge 2.75" shells are so much cheaper than any other gauge or length. The 12 gauge shotgun has evolved over time, and once upon a time the typical 12 gauge sold had a forcing cone only 2.5" ahead of the rear of the barrel. You will find a lot of British shotguns with 2 and 5/8" chambers. You will find the 3" and 3.5" guns also.

Manufacturers being guided to some extent by lawyers, and a quick way to avoid lawsuits from persons putting 3" shells in 2.75" guns being to make all guns 3", most manufacturers just make 3" guns today. There is a slight penalty in weight for doing this, but if that penalty is not important, the manufacturer's way is clear.

If you ever become a shotgun handloader, you will learn a lot more about shotshells. I have learned that in a 12 gauge I can make 3/4 oz of shot do everything to a clay bird that factory 1 and 1/8 oz will do, and beat my shoulder up a lot less. I can load ammo that will make a really tightly choked shotgun that is a family heirloom shoot much looser patterns, such that I can shoot Skeet with it. I can load non-toxic, but ballistically inferior steel shot to screaming velocities, and at safe pressures, such that I can cleanly and humanely take ducks with it. These specialty shells are not loaded by the factories, and if loaded by the specialty loaders are available at much higher cost.

Re: Shell lengths: what difference does it make?

Posted: Sun Jan 20, 2019 12:18 pm
by dougb
Shotgun shells are confusing. Length, gage, high brass vs low brass, magnum load, lead vs non toxic, weight of shot, size of shot. Decide on what you are doing, and ask a friend who uses a shotgun for a recommendation. We won't even talk about chokes yet.

Re: Shell lengths: what difference does it make?

Posted: Sun Jan 20, 2019 1:37 pm
by Bisbee
But to cut through the confusion, “if it fits, go ahead and shoot it,” tends to work well with modern shotguns.

Not ones from before the 1920’s however.

Re: Shell lengths: what difference does it make?

Posted: Mon Jan 21, 2019 8:24 am
by polymath
Thanks everyone; very informative.

Re: Shell lengths: what difference does it make?

Posted: Mon Feb 11, 2019 12:45 pm
by lsj74
I was told you can shoot shorter shells just fine. The chamber is made to fit the shell uncrimped.
The problem with shooting a 3 1/2 inch from a 3 inch gun is when the crimp opens up it goes into the barrel and creates a restriction and can cause a spike in pressure.

Re: Shell lengths: what difference does it make?

Posted: Fri May 17, 2019 4:52 pm
by MikeRossi
I don't want to address the part of your question relating to what shells are compatible with which guns. Except that; multiple shotguns that take different ammo whether gauge or shell length require extra mind to safety.

As for the other part of your question, about power. I longer shell holds more pellets. Note on boxes or on the shells themselves they will be marked 1 ounce, 11/4 ounce, 11/2 or 2 ounce. Rarely a shell will contain more than 2 ounces.

More pellets give you a denser shot cloud. They also reduce velocity which improves the shot cloud (pattern) even more. Most hunters and shooters will tell you this allows you to shoot farther or it is better for larger birds, such as geese. In turkey hunting the only place to shoot is the head/neck - so more pellets are important. However - a longer shotshell or any other manufacturer claims (after-market chokes, long barrels, high velocity, or whatever fiction their marketing teams concoct does not make a shotgun effective much pass 40 yards.

I use 3 inch shells for geese and turkey. But most sources will indicate their use for ducks. I do and have done as much duck hunting as anyone alive today and I use 2/3/4 shells for ducks, as well as pheasant.

More pellets to strike a stationary turkey in the head/neck region is intuitive. But flying game birds requires explanation. Small game birds - woodcock, rail, snipe, mourning doves, quail; and medium size grouse, partridge, small ducks like teal, require a dense shot cloud - because they will sometimes avoid a pellet strike because of "holes in the pattern". But the same is true for large ducks (mallards) and pheasant So you use small shot like number 7 steel. What you dont do is try to fix that by a tight choke or 3 inch shell.

Geese are larger so they can't "fit" through the shot cloud like a dove. I have good results with number 2 steel shot which is larger than 7 shot. Larger means less. Although a goose's body will catch more pellets because it is bigger, a third of them strike where they don't harm the goose. So, by using longer shells I go only up to 3 inch, never larger, it puts more pellets on target (the target's soft spots that is).

Now if you are paying attention, you are wondering why not use the same 7 shot. Most hunters will tell you the goose is larger, so to kill it, larger pellets are needed. That may or may not be true. I have killed them at close range with 7 steel target loads that I use for ducks. But I cannot say with certainty what they will do at normal range of say 30 yards. Since number 2 steel shot works very well with no issues, I have had no reason to "experiment" on live game. I will say this, however, regarding the other reason you might here for using larger shot - "it kills at longer distances". As I already said, nothing yet invented, or ever likely will be invented, makes a shotgun consistently reliable beyond 39 or 40 yards. If you are a true "expert" that shoots exceptionally well, you might be consistent out to 45 yards.

One more point: If you take up duck hunting, you will probably be advised to use number 2 shot. It is the hunters that use 2 shot or a similar size like 1 or 3; that are wounding all the ducks. The more they wound, the more they think they have to use bigger pellets. What is happening is they are only putting a few pellets into the duck, because it is smaller than a goose, and if those pellets happen to hit a soft spot you got a dead duck. But the odds are if only 5 pellets are hitting it, that wont happen. Learning to shoot better, and shooting closer to 30 yards then 40, and not beyond 40; is of course, a big part. But the large shot is a common denominator, don't fall for that myth.

The next thing they will try is a tight choke. But that is fine if your shot is perfect. But when it is not (most of the time) the bird is what we all "fringed". The tight, full choke although sending a dense pattern in its enter, produces a "fringe" effect - think of the planet Saturn. That fringe is less dense than a normal choke. The result is there STILL is only a few pellets hitting the duck.

Recipe: Ducks and Pheasant: Modified choke with 2.75 inch light target loads containing number 7 STEEL shot. Geese: 3 inch, number 2 STEEL shot. All other game birds and rabbits such as mourning doves, woodcock, rails, snipe, all species of quail, all species of grouse, all species of partridge - the same shell I indicated for ducks and pheasant, with a modified choke if pheasants may also be encountered. If there are no pheasants or the season for them is closed, us an improved cylinder choke.

Not what you heard. Not what you read. But I have been hunting since 1974 and I seldom lose a bird that I shot.

Re: Shell lengths: what difference does it make?

Posted: Fri May 17, 2019 8:00 pm
by polymath
Very good info, thanks!