Introduction
The breadth and width of available rifle caliber cartridges can be overwhelming.
Humans have been using brass-cased cartridges since before the American Civil War. That has given us ample time to create, innovate, tinker, and iterate new cartridges and calibers for our rifles.
What Caliber is My Rifle?
So you inherited a rifle, but you aren’t sure what caliber it is. Don’t just guess. You need to determine what the appropriate cartridge is definitively, or you risk a catastrophic failure and could end up injured or worse.
First, caliber is a means of measuring the diameter of the projectile.
Cartridge is the correct term, although, in colloquial speech, cartridge and caliber are used interchangeably.
Look at the barrel of your rifle and find the listed cartridge. Look at the receiver if you cannot find the cartridge listed on the barrel.
If you are still unsure, take your firearm to a qualified gunsmith, who will be able to tell you the correct cartridge for the firearm and even give the firearm a good once-over to ensure its safety.
How to Choose the Right Cartridge
Choosing the right caliber or cartridge is important. If you go hunting moose but only use a rifle chambered in .22 long rifle, you will not have a very successful outing.
Understanding the pros and cons of each cartridge will help you make good choices.
Rimfire vs Centerfire
Rimfire
Rimfire cartridges rose to popularity in the early days of cartridge-based firearms before centerfire priming had been made reliable.
Rimfire cartridges have the priming compound in a hollow space on the rim of the cartridge. When firing a rimfire cartridge, the rim of the case is contacted by the firing pin setting off the priming compound and igniting the powder.
Rimfire cartridges are lower pressure than centerfire cartridges because of the nature of this design.
Popular rimfire cartridges include .17 Hornady Magnum Rimfire (HMR), .22 long rifle (.22lr), and .22 Winchester Magnum Rifle (.22 WMR).
Rimfire cartridges are frequently used for hunting varmints and other small game. Target shooting and plinking are also popular pastimes since rimfire ammunition, like .22LR, is relatively cheap.
Check out our guide on the best .22LR rifles if this sounds like a cartridge you are interested in.
Centerfire
Centerfire ammunition has clear advantages over rimfire-based ammunition.
Centerfire cartridges are more reliable, in general, than rimfire cartridges and are less prone to accidental triggerings.
Centerfire cartridges do not need to leave a hollow space in the rim of the cartridge and therefore have stronger bases and are better able to handle higher pressures.
Centerfire ammunition is fired through the ignition of a primer located in the center of the case’s base or head. This primer ignites when struck by the firearm’s firing pin, which ignites the cartridge’s powder.
Two main types of primers used with centerfire ammunition are Boxer primers and Berdan primers.
In the United States and most of the world, boxer primers reign supreme. Boxer primed cases can be easily reloaded as replacing the primer is simple with the appropriate reloading equipment.
Berdan primers are more complicated to reload, and most who reload in the United States do not attempt to reload their Berdan-based cartridges.
30-06, 30-30, .223/5.56×45 NATO, .308/7.62 NATO, and many more popular cartridges are all centerfire.
If you plan to hunt almost any animal bigger than a coyote or shoot many distances past 100 yards, you are going to be doing so with a cartridge in the centerfire caliber.
Purpose
The sheer amount of available cartridges can be overwhelming when looking at rifle cartridges. Determining the purpose of the cartridge goes a long way in determining which cartridge is the right one for a given situation.
Hunting
The right hunting cartridge depends on the type of animal you intend to hunt. Hunting varmints and other small game at short to medium range means these animals can be hunted with lighter, lower recoiling cartridges.
Therefore, smaller, lighter rifles can be used. .22LR and .22 WMR are both very popular cartridges for these uses.
When hunting varmints and small game at medium to long range, especially when hunting the more sturdy or resilient of these animals, you will need to step up to a more effective cartridge. .223/5.56×45 NATO is a great example of a cartridge that is much more effective while maintaining light to moderate weight and recoil.
The majority of game available in North America can be hunted with the next step up in ammunition. Venerable cartridges like the 30-30 Winchester and more modern cartridges like 6.5 Creedmoor are excellent for bringing down deer, hogs, and even black bears.
While both of these cartridges are capable of being effective, they may not be effective in the same ways or the same environments. There are hunters who will take their 6.5 Creedmoor hunting and take shots of over 500 yards. Doing it with a 30-30 Winchester rifle would be unethical.
200 yards is the maximum effective range for 30-30 Winchester. Despite this, the 30-30 Winchester is anecdotally said to have taken more deer in North America than any other cartridge.
This means that the conditions being shot in are important as well. If you are hunting the woods of Ohio or Alabama, your cartridge selection might be different than if you are hunting the mountains, canyons, and ranges of Idaho.
Hunting North America’s largest or most dangerous game requires the most effective cartridge. Several options exist, but the .300 Winchester Magnum has earned a reputation for effectiveness.
If I am hunting a Moose or a Grizzly Bear, I am not going with half measures. You want to know that when you pull the trigger, your cartridge is going to do its job; that is assuming you, the shooter did yours.
Target Shooting/Plinking
When target shooting or plinking, it is important to consider multiple factors. Distances to be shot, the cost of rounds, and the ultimate purpose of the shooting. If your purpose is just to have a good time at the range, oftentimes something like .22LR will serve that purpose and do so cheaply.
.22LR also has several shooting leagues that can scratch the need to participate in a competitive activity. That being said, shooting longer distances is very rewarding, and some competitive shooting activities are tailored to tactical skills where cartridges like .223/5.56×45 NATO, 7.62×39, or .308/7.62×51 NATO are preferred.
Knowing what you plan to do or hope to accomplish with your shooting will help you decide which cartridge you want to use.
What Bullet Type Should You Use
Now that you have decided on a cartridge, you have to decide which bullet type fits what you want to do with your rifle.
Most bullets are of a type called a “spitzer” bullet. This is the shape that most think of when they think of rifle bullets, nice and pointy.
Spitzer type bullets have been designed to provide the most efficient ballistics to the bullet possible. Modern bullet design and the use of computers has made these bullets more effective than the spitzer bullets of years past.
When selecting your bullet, the purpose you intend to use it for is very important. If hunting with a 30-06, you will not necessarily use the same bullet for a deer as you would a black bear.
Thin skinned game animals like the deer are hunted using a bullet designed to expand and dump its energy into the animal. Bullets that create large wounding channels and lead to the animal expiring quickly and humanely are important.
Conversely, a tougher animal with a thick hide and strong bones will need a more robust bullet. You want something that provides not just solid expansion but also deep penetration to reach the animal’s vitals and lead to as quick and humane a harvesting as possible.
There are many manufacturers of high-end ammunition today. Animal-specific loads have been developed to hunt everything from varmints and other small game to hogs, deer, moose, and bear.
Ammunition Grades: Premium vs. Non-Premium
This is a tough debate to pick a winner in. Many of today’s standard ammunition loadings perform better than premium loadings from twenty or thirty years ago.
Premium ammunition is just that. The highest quality components are used to provide outstanding ballistic performance.
Whether you are ringing steel plates at 500 yards or taking a trophy buck, premium ammunition will perform to a level that most non-premium ammunition cannot match.
That being said, huge numbers of animals are harvested every year using solid non-premium loads.
When a deer or hog gets shot, I guarantee you it doesn’t think, “Whelp, that bullet only cost the hunter $1; I guess I will shrug off the shot and go on my merry way.” Assuming the hunter did their job, it is just as dead as the animal shot with a $3 bullet.
For more challenging shots and more challenging animals, the best choice is to go with the best you can afford.
Why would you spend hundreds or even thousands of dollars on gear, spend hours getting to and from the hunt, hours practicing, only to miss out harvesting an animal because you chose to save a few dollars when it finally came time to make the shot?
Special Loads
There are many special loads to help ensure every shooter’s various needs are met. Not everyone hunts in the same type of environment, and not every hunter is built the same.
Ammunition manufacturers have spent a lot of time trying to ensure everyone can find the appropriate loadings for their preferred cartridges.
A great example of the special loads available is when discussing recoil. Reduced recoil loadings have risen in popularity in recent years.
Young shooters, small shooters, shooters with medical conditions, and other recoil-sensitive shooters have been able to more fully enjoy shooting using the variety of reduced recoil loads now available.
On the other end of the spectrum, you can find loads designed to push cartridges to their limits.
Some loadings seek to squeeze every last drop of potential from cartridges. They push rifles to their limits but, in turn, can generate muzzle velocities, energies, and ballistic efficiencies you would never see in a “regular” loading, much less a reduced recoil loading.
Another area we see special ammunition is in bullet material. Lead has long been the dominant metal for bullets. Some states have begun to move to restrict lead-based bullets legislatively.
There are also hunters who prefer to avoid using lead-based ammunition and the potential risks of exposure to lead.
To meet this need in the market, manufacturers have begun to produce lead free bullets. This is a great example of the firearms ammunition industry evolving to meet the changing needs of the firearms community.
FAQs
What’s the difference between a cartridge labeled 30-06, a cartridge labeled .308, and a cartridge labeled 7.62×39?
The above cartridge names are the various ways cartridges have been identified. 30-30 uses an older style for identifying cartridges. It means the projectile is .30-inches in diameter and holds 30 grains of powder.
.308 and other cartridges that use similar naming conventions simply state the diameter of the bullet in inches without giving case capacity or length. .308 would be a .308-inch diameter bullet.
Finally, 7.62×39 and other cartridges with similar naming functions have a bullet that is 7.62 millimeters in diameter, and the case is 39 millimeters long.
Are “larger” bullets always more powerful?
Larger bullets are only sometimes more powerful. The effectiveness of a bullet depends on many factors. Bullet design, velocity, and projectile mass all determine how effective a bullet or cartridge is. Terminal ballistics, the effects of a projectile when it hits the target and the energy transfer to the target, are incredibly important when determining how “powerful” a bullet is.
Is there a “best” cartridge?
There is no “magic bullet” when selecting the best cartridge. Every shooter will have different needs, and every situation will have variables that could change the best cartridge in a given situation. You need to consider the factors shaping your situation and select the best cartridge.
Last Words
The width and breadth of available rifle cartridges and picking the best cartridge and caliber from those available can be daunting. It can be, with the proper research and mindset, a very rewarding task.
Ammunition manufacturers have spent millions of dollars trying to ensure the right cartridge is available for every shooter and situation. Have they succeeded in this? Most likely not, but they have done an excellent job covering their bases and giving consumers excellent options.
If you have a question about a specific cartridge or what cartridge you should pick for a certain hunt or activity, drop it in the comments. Now, pick out a cartridge, and a rifle, and get out and shoot. Whether you are hunting, target shooting, or just plinking, being outdoors is incredibly rewarding.
