It’s impressive how many different rifle cartridges there are to choose from these days.
No matter what you’re doing, you have dozens of suitable chamberings to chose from,
and ammo companies and wildcatters are always coming up with new ones.
Shotguns stand in stark contrast to this. The number of gauges in common use has only
decreased over the years, and now, there’s just a handful of bore sizes to chose from;
most of which have fairly well-established niches.
This makes selecting a chambering and finding ammunition for your shotgun quite an easy
matter compared to most other long guns. However, there is one wrinkle here; the matter
of shell length. Unlike most modern rifle chamberings, shotshells of the same gauge
come in a variety of different lengths, and most shotguns are able to accept multiple
shell lengths. If you’re getting into shotguns, it’s
important to understand what shell length is, what lengths are available in your gauge,
and what lengths your shotgun can and cannot handle.
Let’s get one very important distinction out of the way right off the bat.
A shell’s length refers to its overall length in its fired state.
This can cause some confusion, since the mouths of shotshells are usually folded or rolled
over - a process called crimping - in order to contain the payload.
Crimping a shotshell results in a shorter overall length prior to firing - though exactly
how much shorter varies depending on the nature of the crimp.
While unfired length and crimp types are worth discussing - and will be discussed in another
video - it’s the unfolded or fired length that’s the standard length measurement for
shotshells. It’s what the number printed on the shell
or packaging is referring to, and when someone mentions a shell’s length, they almost always
mean the fired length. The reason for this is that a shotshell’s
payload needs to have an unrestricted path as it moves out of the mouth of the hull,
through the forcing cone, and into the barrel’s bore.
Whatever its crimped length is, if the shell is longer than the chamber in its open, unfolded
state, the end of the hull will extend into the forcing cone, and create a constriction
that the payload is forced to squeeze through.
Shotshells have relatively low peak pressure limits,
and use fast-burning propellants, so even minor obstructions like this can easily
cause pressures to spike beyond what the barrel and action are designed to contain.
Patterns and function will likely suffer, and repeated use of overly-long shotshells
can damage or even destroy a shotgun. Therefore, you should be aware of how long
your shotgun’s chamber is, and not use any shells longer than that.
But as you may have already noticed, because a shotshell can be significantly shorter when
it’s crimped, it may seem to fit in a chamber that’s actually too short to fire it safely.
So, don’t assume that a shell is safe to use just because it chambers; always confirm
a barrel’s actual chamber length before selecting shells for use in it.
Shotgun barrels should be engraved with their chamber length, somewhere - refer to this
over any markings elsewhere on the gun, as many shotgun designs allow the barrel to be
easily replaced or changed.
On the other hand, as you may have already
known or guessed, a shell that’s shorter than the chamber is not a problem, because
the payload still has a clear path.
Like many common revolver cartridges, standard
shotshells have little to no taper, and headspace on their rims. So, just as a .357 Magnum revolver
can also chamber and fire shorter .38 Special cartridges, a shotgun with a 3”-long chamber
can also safely fire 2 ¾” and shorter shells.
And as with magnum and parent revolver rounds,
in cases where one shotshell length has an increased maximum working pressure, it is
also longer than other shells of the same bore size; so a gun built for a longer, higher-pressure
shell will also be strong enough for anything shorter.
The fact that shotgun chambers can shoot shorter shells, but not longer ones, is also why fired
shells will sometimes come in below their advertised length if you actually measure them.
Length tolerances for shotshells allow for little - if any - extra length,
but a very large amount of slop is permitted in the other direction.
Therefore, ammo companies can choose to aim
a little low when manufacturing hulls. A slightly short hull is no problem as long as the intended
payload still fits, and it’s a cheap and easy way
to ensure that the shell won’t be over spec.
Alright, but why are there different shell lengths anyway?
Well, the primary reason for different-length shells is to accommodate different payloads.
A longer shell provides more space for heavier
shot & powder charges, large pellet sizes, and/or lower-density shot materials.
It’s worth mentioning that there’s no reason a small amount of shot can’t be loaded
into a long shell by using a taller wad or lightweight fillers to take up the extra space.
However, to use a longer shell, you need a longer, heavier chamber; and for repeating
shotguns, a longer & heavier action as well.
Heavy magnum loads are unnecessary for many
shotgunning activities, and for guns intended for these lighter applications, shorter chambers
and actions can significantly reduce bulk and weight.
Thus, ammo manufacturers prefer to use shorter shells for lighter payloads, so that their
product can be used in both lightweight and magnum shotguns of the same gauge.
So, let’s talk about what lengths are out there for the various gauges.
Most of the currently-used shotgun shell sizes come in just a handful of standard lengths,
but there are also many less-common shell lengths that you may run into.
It’s good to be aware of the different shell and chamber lengths and their capabilities,
so that you can better choose a gun and ammo that meet your specific needs.
Easily the widest variety of shell lengths have been made for the long-popular 12ga.
However, the majority of 12ga shotshells these days are 2 ¾ or 3 inches in length.
Most current & recent-production 12ga shotguns have either 2 ¾” or 3” chambers, though
the more versatile 3” chambers seem to have become the standard these days.
A 3” 12ga chamber will allow you to shoot shells containing anywhere from ¾ of an ounce
to 2 ounces of shot, as well as nearly any 12ga slug load.
For most folks, this range will cover anything they would realistically need to do with a shotgun.
But, there’s always someone who wants something bigger.
The 3 ½” 12ga super magnum provides significantly more space and a higher peak pressure limit
than other 12ga chamberings. In anticipation of the upcoming ban on lead
shot for waterfowl hunting, it was introduced in the late 1980s to provide improved performance
with low-density steel shot, which was the only nontoxic option at the time.
It’s still commonly used for steel, but its extra space and higher pressure also allow
it to launch more than two ounces of lead and other high-density shot for things like
turkey & buckshot hunting. It can certainly be argued that such heavy
payloads rarely offer enough benefit to justify their ferocious recoil, but since a 3 ½” 12ga chamber
will also shoot any shorter 12ga shells, it is undeniably an extremely versatile option,
even though super magnum guns are generally less-than-ideal for applications
that call for lighter loads.
2 ½”-chambered 12ga guns were popular for a long time,
especially in Europe, and since many of these older guns are still in use,
a number of companies offer a range of 2 ½” 12ga shotshells.
Similarly, 2 5/8” shells & chambers were common in the early-to-mid 1900s in North America.
Some loads still use this length, but you’ll likely have an easier time finding
2 ½” shells, especially in the US.
Other lengths have been produced specifically
for unusual specialty shotguns, such as the two-inch 12ga shells used in some ultra-light
British doubles, or the 60mm shells sized for the box magazines of the Techno Arms Mag-7.
If you’re interested, Ian at Forgotten Weapons recently posted a video on the Mag-7 shotgun
that’s worth checking out.
Various other short 12ga shells have also been offered;
but I’ll talk more about short shells a little later.
The once-popular 10ga has seen a fair number of shell lengths as well, but 2 7/8” and 3 ½”
eventually became the two common ones. However, the former has pretty much faded
from use, as the 10ga has long since been displaced as a general-purpose bore size.
If you can find them, a handful of light 2 7/8” 10ga shells are still made for use
in older guns, but modern 12ga or 20ga loads can easily match or surpass the payloads in
these old-fashioned, low-pressure shells - while also benefitting from modern performance-boosting
shotshell tech.
The spacious 3 ½” 10ga magnums are about
the only thing that’s kept this old bore size out of obsolescence. 3 ½” chambers
are the norm for the few 10ga shotguns still being produced, and pretty much all 10ga shotshells
from major manufacturers are 3 ½”.
Going back down to something more popular,
the 20ga has seen its own share of shell & chamber lengths over the years.
In the early 20th century, the standard 20ga shell length was 2 ½”, but as with the
12ga, 2 ¾” and 3” chambers eventually became the current norm, with 3” chambers
becoming increasingly prevalent in order to give shooters the option of slightly heavier payloads.
20ga shotshells are widely available in both lengths,
and a number of ammo companies also still produce 2 ½” shells for
older guns with shorter chambers.
With the neglected 16ga, you’re looking
at 2 ½” or 2 ¾” shells these days. Either shell length can accommodate a payload range
that’s very nearly the equivalent of the combined 2 ¾ & 3” 20ga.
2 9/16” hulls and chambers used to be the standard for the 16ga, and remained common
up until the mid-20th century, but these shells are tough to find nowadays. Many 2 9/16”
chambers can be safely lengthened to 2 ¾”, but some repeating shotguns might not cycle
the longer shells reliably without further modifications.
For these guns, 2 ½” shells may be a better choice.
Some older 16ga shotguns were manufactured with 3” chambers, and for a time,
ammo manufacturers offered both loaded and empty 3” and 2 7/8” shells for use in them.
However, these weren't magnum shells intended for heavier payloads;
the extra space was instead used for a longer wad column.
This was apparently something of a fad at
the time with the three popular mid-size bores. Some shotgunners believed that the extra wadding
improved patterns by creating a better gas seal, and providing more cushion for the shot.
Whatever the actual benefit, the idea eventually went out of vogue,
and while the 3” 12 & 20 gauges found success later on as magnum chamberings,
the 3” 16ga was forgotten.
With the little 28ga, the most common chamber & shell length is 2 ¾”, though 2 ½”
28ga hulls with lighter payloads were popular very early on, and 2 ½” shells are still
being manufactured for low-recoil shooting, or use in older guns.
2 7/8” 28ga shells were used for heavier shot payloads in days past, but with modern
propellants and components, a 2 ¾” 28ga shell can now hold up to one ounce of lead shot.
However, ¾ of an ounce still seems to be the sweet spot for this little shell,
and the lightweight guns that fire it.
The idea of a 3” shell seems to get tossed around every so often,
and a few 28ga shotguns have even been manufactured with anticipatory 3" chambers.
Personally, I can’t think of any good reason for a 3” 28ga;
it won’t fit in the 28ga shotguns that folks already own, and it won’t
do anything that the more popular 20ga couldn’t do better.
With the diminutive .410, the common shell lengths are the 2 ½” standard, and the
3” magnum, though "magnum" here is really only a relative term.
.410 shotshells as short as 2” have been used in some older shotguns, as well as converted
military rifles such as the Ishapore Lee-Enfield conversions used in India -
although those guns used shells formed from rifle cartridges,
which is actually something you can do with the .410.
There’s another good Forgotten Weapons video
with details and history on these Ishapores that I’d recommend checking out.
If you have a .410 with a short chamber, 2” shotshells are still offered by some manufacturers.
Reaming out a short chamber for the more common 2 ½” shells is often possible, as well.
Looking at some rarer bore sizes for a minute, shells for the now-obsolete 8-gauge ranged
from 3” to 4 ¼” in length.
Loaded 8ga shells are neither cheap nor easy to find;
but if you reload, the currently-produced 3 ¼” industrial 8ga hulls can be modified
for use in shotguns, or you can buy 8ga brass cases in a variety of lengths.
What limited ammo is currently manufactured for the 24 & 32 gauges seems to be mostly
2 ½”, but I have heard of 2 ¾ and 2” 24-gauge shells as well. Shotguns chambered
for the latter would probably require handloads or custom ammo.
In addition to what I’ve talked about here, plenty of other less-common shell lengths
have existed at one time or another for the various gauges, especially if you look back
at the early days of cartridge shotguns, when things were far less standardized.
But even today, most shotgunners will come across unusual shell lengths - either on the
internet, or store shelves.
As I mentioned earlier with the 12ga; most nonstandard-length shotshells
manufactured these days are short shells
containing light or specialty payloads.
It’s also fairly easy for handloaders to
cut standard hulls down and load their own short shells to feed older guns, or get more
reloads out of a hull. Powder companies have even published load data for popular 2 ¾”
target hulls cut down to 2 ½ or 2” lengths.
When loaded with shot or slugs, these special
short shells often appeal to owners of tube-fed repeating shotguns, since the reduced length
can allow for a significant jump in capacity. It’s an attractive idea, but repeaters designed
for standard-length shells can have trouble feeding or ejecting short rounds
with complete reliability.
This is most likely to be the case with extremely-short mini-shells below 2” in length.
Less extreme short shells will often function
properly however, and while they may not double capacity, they can still provide an extra
shot or two over standard-length ammo.
Mini shells are also marketed as having very
low recoil, due to their lighter-than-typical payloads.
While not untrue, if light recoil is the primary goal, there’s no reason similar light shot
charges can’t be loaded into shells that are long enough to function reliably.
As I mentioned earlier, all that’s needed is a tall wad to take up the unused space.
Shells that are longer than normal are much less common than short shells, but they were
and are out there. Current examples include the 3 ½” 20ga
developed as a dedicated slug chambering for single-shot guns with rifled barrels;
and the high-pressure “12 Gauge from Hell” wildcat that uses custom-turned brass hulls,
or blown-out & re-rimmed .50 BMG rifle cases.
Since they require custom-made or specially-modified
shotguns with long chambers, you’ll rarely - if ever - see these long shells for sale
in gun shops. They’re almost always home-made
or custom-made shells intended for very specific purposes.
Well, I’ve talked about shell length for nearly 15 minutes at this point.
If you’re still awake, hopefully you have
a good understanding of what shell length represents, and what lengths you can safely
use in your gun’s chamber. If you don’t have a shotgun yet, and you’re
watching this series to learn some basics and figure out which gauge and chamber length
best meets your needs, good for you. You’re going to be much better off than the vast
majority of first-time shotgun buyers.
Please don’t hesitate to leave a comment
if you have questions or feedback, or if you want to mention or discuss some old or unusual
shell length that I didn’t include here. I’m always interested in hearing about new ones.
Until next time, please shoot safely and responsibly,
and help promote and protect our shooting hobby by educating others about it.
Help! I'm trapped in a subtitle factory!