Current small arms technology is in an
evolutionary stage, rather than a
revolutionary stage.
Revolutionary was WW-II era, when small arms like the Stg-42, MG-42, M-1 Garand, and Thompson SMG were fielded.
All truly game-changing in their relative portability, rate of fire, and accuracy/volume of fire.
Evolutionary is the current state;
- Bullet technology is generally a lead or steel core wrapped in a copper-based jacket, with periodic refinements in aerodynamic shape (Berger's recent 'hybrid VLD Secant/Tangent ogive bullet) or minor tweaks to materials (bullets, shot, etc).
- Powder technology is generally stagnant, with minor improvements in composition (burn rate retardants, consistency of powder lot improvements, consistency in varying environmental temperatures, powder shape tweaks, double-base versus single-base
- Casing technology - Lapua and Norma, in particular, have done an incredible job of making the simple brass cartridge into a remarkably strong, consistent, and durable item. Neat trick too, because a cartridge needs to be very hard at the rear and relatively soft at the front (neck/shoulder). There are also steel cases (Russian, and Wolf Russian imported), non-reloadable Aluminum (Aluminium) cases, or the odd experimental polymer cased or caseless ammo.
- Polymer frames - M-16 is the first major weapon system to make significant use of polymers for major components. As polymer technology increases, more structurally critical components can be made of polymers. As an example, the original M-16 used aluminum for the upper and lower receiver - today, with current polymers, that aluminum structure could potentially be replaced with a high-strength polymer, that wasn't available in the 1960's.
- Front case ejection - (FN F-2000, for one); Anyone that's had the guy firing to the right of them sending hot brass at their neck and down their shirt can tell you this is a welcome improvement.
- Ergonomics - There is comfort in the feel of the familiar, but the familiar can be improved on. The FN SCAR takes the general control layout of the familiar M-16/M-4 - then improves stock adjustable length, adjustable cheek weld, charging handle location (ala MP-5), and accessory mounting flexibility.
- Refinement of caliber - 5.56 volume-of-fire versus 7.62 power-per-round on the assault rifle side, with a fringe of intermediate potential rounds like the 6.5 Grendel, 6.5x47 Lapua, etc. (Personally, I think the 6.5x47 Lapua is the best of both worlds - bullet is 71% of the weight of the 7.62 round but has better ballistics and energy retention at range, casing is outwardly similar enough to the 7.62x51 to use the same magazines, and pressure curve is similar enough that gas-operated weapons could be converted from 7.62x51 to 6.5x47 with little more than a barrel change). Again, for a military assault rifle & light/medium machine gun caliber, it's (as usual) a dance between 'light enough to carry a bunch' and 'powerful enough per individual round'.
- Portability versus power - a man portable .50 cal sniper rifle? Haven't seen this much power in a sniper rifle since WW-I (when they had anti-tank rifles). Let that sink in a moment.. anti-tank RIFLE. For an intermediate round, the .338 Lapua is a good balance between the monstrous .50 cal and the anemic (for a sniper round) 7.62x51
Could go on for quite a few more points, listing the little refinements and tweaks to small arms design.
But, if you want a peek at what the next
revolutionary small arms technology is going to be, read a few of the US Army Ballistic Research Laboratory reports of the last 20 years. There are a Crap-tonne° of research papers on rail gun technology. As soon as there's a breakthrough in energy storage technology and propulsion coil efficiency, rail guns will be here.
° - crap-tonne. Combination unit, like foot-pound, derivative of the basic unit
shit load. (144 shit-load = 1 ass-load)