Another primary purpose of a rifle case is to actually protect your gun. The best rifle cases have sufficient padding to hold a rifle immobile, providing shock absorption while securing the firearm inside the case. This prevents the rifle from bouncing around and possibly altering your zero.
As mentioned above, if you’ll be traveling via plane with your rifle, you will want the protection offered by a hard-sided case (and regardless, it’s required). But in most other cases, a soft-sided case is much less cumbersome, offering sufficient protection balanced with lighter weight and ease of use.
On the subject of protection and security, it’s important to note that a gun case is a smart way to transport a gun but is not the best place to store a gun in your home. Storing a gun at home in a locked, hard-sided case can be secure, but it is bad for your rifle. That secured case does not breathe, so if you’re storing your rifle between hunting seasons, you should actually leave the case open, which makes it – obviously – not secure anymore. And among the soft-sided variety, even the best rifle cases are difficult – if not impossible – to lock in a way that is truly secure. Bottom line: buy a rifle case for transporting, and keep your rifles in a gun safe at home.
In addition to protecting the gun, the best rifle cases will hold up to hard use themselves. The required durability of your case depends mostly on what you intend to put it through. What kind of conditions will your case be exposed to? Assuming you’re not strictly limited to an indoor range, you want to choose a rifle case that can take a beating outdoors.
For a soft rifle case, the fabric should be tough, like asturdy waxed canvas or ballistic nylon. Waterproof or water-resistant fabric will not only keep the moisture out of your gun, but will also ensure that the case itself can hold up to wet conditions.
Details like straps, hardware, and stitching are also important. Make sure the handles and straps are reinforced and attached well. An adjustable shoulder strap with a sliding pad (that you can adjust depending on how you're carrying the case) will make trekking long distances with your rifle much more comfortable. Reinforced nylon or tough leather make fantastic materials for straps and handles.
Be sure the case will fit your rifle, scope, and other needed accessories. In order to choose the right length for your rifle, measure from the butt to the end of the barrel, and add 1 ½ to 2 inches. (A good rule of thumb is to choose a case that’s a couple of inches longer than your rifle to be sure it fits inside easily.)
Remember to also check that the case is wide or tall enough to accommodate any optics you have mounted. If your rifle has a mounted scope, measure the rifle’s height together with the scope to be sure it will have a wide berth when the case is shut.
Finally, consider space that you’ll want for extra gear and accessories. One capacity-related advantage of going the soft-sided route is that the best rifle cases have pockets on the exterior that can be easily accessed without taking down the case and opening the main compartment.