From all of the above it is possible to draw up a specification for the characteristics of an 'ideal' rifle, common to all calibres and even regardless of whether the preferred type has a traditional or bullpup layout, as follows:
1. Maximum reliability, even under the most adverse conditions. This also includes durability; tolerance of the kind of rough treatment common in warfare. Reliable functioning requires an action which is protected as far as possible from the ingress of dirt, and designed to expel any dirt which does get in. There should be a surplus of power available to drive the action and positive extraction, which implies a piston-type gas operation (preferably with an adjustable valve). Cleaning equipment should be provided in a compartment somewhere on the rifle.
2. Maximum ease of use for both right and left-handed users (few weapons score well at this). All controls should be ambidextrous, and all fall readily to hand and be operated in an instinctive way. It is common to combine the safety catch with the single shot/automatic fire selector, but this is arguably not ideal; a safety catch needs to be instantly and silently flipped on and off without moving the hand from the firing position and is best given just that function to do. (It could perhaps be a spring-loaded flap located within the trigger guard which has to be pushed to one side before the trigger can be pulled; it is then unnecessary to have to remember to switch it on and off.) The fire selector should be different, perhaps the ideal being the Steyr AUG's trigger control; normal pull for single shots, heavy pull for automatic fire; again, no switches to remember. The magazine release catch needs to be convenient to use by the hand grasping the magazine, but must not be easily hit by accident. The magazine should also be easy to locate in the magazine well, and click into place with a simple vertical push, without needing to be rocked from side-to-side or front-to-back.
3. Compactness for use in vehicles and in street-fighting, combined with a long enough barrel to provide the ballistics required to retain maximum effectiveness out to at least 300 metres. This implies either a bullpup layout or a folding/telescoping stock. In the latter case, care needs to be taken to ensure that the stock is quickly and easily extended, but is comfortable to use and remains rigid despite much use and abuse.
4. A flexible sight mounting system, which can accept a standard telescopic sight or night sights, but also has simple iron sights for emergencies. The ability to fit a range of accessories such as grenade launchers, torches, laser pointers etc is also important.
5. Other issues include:
a. a magazine hold-open device, which holds the bolt back when the last shot has been fired. This would seem obvious, but an astonishing number of weapons do not have it; the German G3, HK rifles generally, SIG and the original FAMAS are among the culprits (the later FAMAS has it). Their users only discover that the magazine is empty when they pull the trigger and nothing happens.
b. a trigger pull light and crisp enough to permit accurate firing on semi-automatic (unimportant in fully automatic fire, which should be for short-range emergencies only; in most circumstances, a trained rifleman will score more hits with rapid semi-automatic fire).
c. a charging handle (accessible to both hands, of course) which can also be used to force home a reluctant cartridge, or to kick a stuck case out of the chamber.
d. a trigger guard which permits the use of mittened hands; either one which can be pushed out of the way, or a full-hand guard like the Steyr AUG and the latest FAMAS.
e. a forward handguard shielded from heat build-up.
f. A design which enables the gun to be quickly and easily field-stripped for cleaning, without the risk of losing small parts or reassembling them in the wrong order
There is another important factor which is difficult to describe objectively, and that is the general handling of the weapon. The pistol grip and hand guard should be well shaped to provide a good grip, and the stock should provide a comfortable cheek rest. The gun should feel well-balanced, and come up to the aim naturally. The problem is that people differ in their views on this and, in particular, proponents of traditional rifles dislike bullpups, and vice versa. Finally, and bearing in mind that it is increasingly common to fit accessories of various types thereby adding noticeably to the weight, the weight of the basic rifle should be kept as low as is compatible with durability.