Coalate Small Arms: w/Author notes

Let me start by stating that None of these weapons exist in real-life in exactly the same form they are presented here. The concepts and operation are sound enough, and actually in use; but cartridge dimensions and applications have been invented by me. My purpose in creating this list was to attempt a logical progression of firepower with as few calibers and competing systems as possible. As we have seen with the various popular weapons platforms of the world, one base weapon can be styled to suit particular tasks while using a maximum of like components. This simplifies logistic and manufacturing concerns, as well as reducing problems with cross-training operators onto different platforms. We see this now with AR family weapons being adapted to pistol-caliber for use in urban areas, while still retaining the same outward function (manual-of-arms) and most internal parts of their battlefield brethren.
One may notice that many of the weapons are supressed as a standard feature. This is not to insure ninja-like stealth, nor should one be under the impression that this can be conferred on most ammunition of reasonable power. A suppressed weapon is easier on the operator's eardrums, allowing them to continue communicating with teammates after firing a few bursts. Lightly suppressed weapons also have less muzzle flash and recoil from unburned powder, and many suppressors will outlast the barrel by years when properly designed.
There is some overlap in the calibers I have chosen, and this is not unintentional. I have created some with the intent of allowing a disparity of firepower between local and regional policing forces. The particular classes of cartridge I have tried to create are as follows:
9mm/38special. Considered the bare minimum for personal defense by many, cartridges below this energy level are notorious for delivering less than immediate incapacitation even with perfect hits on target. Loads using good bullet design and adequate powder charge have been proven fight-stoppers for decades. Modern projectile and powder loads have enhanced their ability to even higher levels, although cartridge development is now seeming to favor bottleneck rounds again.
.45 ACP. A classic pistol and carbine cartridge, almost mythic in its killing ability. Ammunition in this class may be loaded to acceptable levels to hunt deer and small bear, although most would prefer a bit more oomph. Bottom and top end of this class, respectively, are the .40 S&W and 10mm. .41 magnum and .357 magnum would be rimmed cartridges in the same range.
5.7x28mm / .22 Hornet. Ironically enough, cartridges that I would be happy to leave almost unchanged, but scaled up just a bit. I upgraded to a 6.5mm bullet simply to allow commonality with the larger battlefield cartridge, allowing greater versatility in loading options, and a slight increase in probable lethality. This is the round found in the P90 carbines used in the "Stargate" television series. A zippy and controllable short-range load; its small case diameter make large capacity magazines easy to design. The new 6.5 CBJ is close to my ideal, while still working in weapons designed for 9x19 NATO.
5.56 & 7.62 Nato / 7.62 Soviet. The modern standard for battlefield, or "assault," cartridges; a majority of nations and armed groups will use one or all of these rounds. The ideal energy from rounds in this class is generally considered to be 1500-2500 ft/lbs, which the smaller 5.56x45mm usually fails to acheive. I have chosen a round roughly analgous to the 6.8 SPC, although a bit faster and more powerful. The flatter trajectory and slightly reduced recoil (over 7.62 NATO) enhance unknown-range and multiple target engagement, without the disappointing terminal performance of .22 caliber rounds.
30-06 / 8mm Mauser. The main rifle calibers of U.S. and Germany for two world wars, rounds in this class have already proven useful for over 100 years. Generally in the neighborhood of 3000-3500 ft/lbs, the projectiles are large and heavy enough to allow small incindiary and explosive payloads for enhanced effects; solidly-built slugs are capable of killing any animal on Earth. Easily capable to 1 Kilometer with an expert shooter, recoil levels are problematic for close-quarters battle.
.50 BMG. A venerable and respected cartridge worldwide, this was originally an anti-tank round; although rather quickly made obsolete for that purpose by armor advancement. Several calibers were created in this range for aircraft guns, close air defense, heavy machine-guns and long-range sniping.
12ga Shotgun. A favorite among many hunters and tactical operators for a reason, it works. The plastic or cardboard hulls can be loaded with almost any imaginable payload, from small pellets to solid slugs. There are multiple novelty loads of dubious value; including fireworks shells and the "Dragon's Breath" round, which acts like a flamethrower. Law enforcement has seen a vast amount of develpment for this cartridge; rubber shot or slugs, beanbag rounds, tear gas, and even Taser rounds for electrical and impact incapacitation.
         While caseless ammunition was considered quite futuristic and advanced when first proposed, many have chosen to largely forgo this story option in the interest of tactically sound writing. The real world, any real world, is a dirty and hazardous place. Rounds will be dropped, smashed, badly stored, and exposed to various chemicals and humidity levels. Preloaded and sealed magazines are fantastic ideas for infantry, but packaging will be inevitably pierced and damaged; and what happens when you have many partially-full magazines that you wish to consolidate? Reloading ammunition is not an immediate concern on the battlefield, but in survival situations, it is better to have components that can be reused. There is the added factor that caseless ammunition generally requires a higher level of firearm design, and can be problematic to unload, particularly in a weapon already heated from prolonged firing. See the end of this document for notes on the weapon types.
Notes on bullet types: Often overlooked is the fact that no bullet is magically going to fit every mission. A hardened, armor-piercing round will dump relatively little energy into a human target, allowing a greater chance of survival; while expanding bullets will flatten and disintegrate against relatively thin steel plate. Thus, many bullet types and a few different powder charges may be available for any given cartridge. Heavy, subsonic rounds are quieter and easier to suppress than a light, fast bullet offering the same total energy. Heavier bullets are also generally less affected by wind or small objects in their path, but may lack the velocity to reach longer ranges accurately.
Finally, I appear to have finished with my rambling and now present a list of individual arms for agents of the Coalate States.

8x30mm: AKA 8R or 8 rimmed. A straight-walled rimmed cartridge specifically for revolver use. Basically identical to real-world .327 Federal Magnum
  RP-05: Med frame revolver, 7 shots. Barreled 7.5-15cm, handles +P ammo well. Common for armed security.
  RP-08: Small frame revolver, 6 shots. Barreled at 5.5-10cm, +P ammo not recommended for constant use. Composite and alloy construction keeps the weight to an unreal minimum. Popular with undercover and plainclothes operators. May have bobbed or shrouded hammer. (UPDATE: See Ruger LCR for real world build)

8x21mm: Slightly necked rimless cartridge, popular for undercover and holdout guns. +P and AP rounds appropriate for some platforms. The rimless design makes "moon clips" neccesary for revolver use, and its larger diameter reduces capacity in a cylinder.
  RP-06: Med frame revolver adapted from RP-05, 6 shots. Barreled 7.5-15cm, handles +P ammo well.
  RP-09: Adapted RP-08, 5 shots. Barreled at 5.5-10cm, +P ammo not recommended for constant use.
  AP-06: Slim autopistol, good for holdout or concealed weapon. 7rd magazine.
  AP-07/c: Full-size automatic, designated service pistol for most urban police forces. High round count and low recoil make it popular. 17rd magazine.
  MP-11: 40rd top mounted magazine. Compact SMG, suppressed barrel. High rate of fire, popular for VIP escort. AP and +P rounds are a good match.

10x23mm: A straight cased rimless cartridge popular for police and military. Good against unarmored targets, and easily suppressed in most loadings.
  RP-07: Med frame revolver, 6 shots. Barrels 7.5-20cm, made for +P rounds. Light or laser modules optional.
  AP-04/c: Standard police sidearm, 12rd magazine. Compact variant for undercover/plainclothes work, 8rd mag. Both may use suppressor or illumination module.
  MP-10: Standard submachine gun, 20cm barrel, 25rd stick magazine. Integrally suppressed. Flashlight/camera combo module assists review of mission events.
  AC-08: Patrol carbine using standard pistol magazines to extend range and accuracy. Basically an extended and stocked AP-04, 35cm barrel.

6.5x26mm (short 6): A bottleneck cartridge useful for man-sized targets out to 300 meters. High impulse, low recoil. Poor terminal performance at extreme ranges. Same rim and case dimensions as 8x21, but there is an observable increase in overall length. Loads include AP, Frangible,
  AP-05/c: A combat pistol of standard design, holding 20 rounds in a removable grip magazine. Standard military sidearm. May be fitted with a suppressor and laser/flashlight module.
  MC-11: Submachine gun in semi-bullpup configuration, 50 round helical magazine. 40cm barrel is integrally suppressed to protect hearing. Vehicle crew primary issue. Underbarrel mount for secondary device. Secondary trigger selection built in.
  MP-12/s: Suppressed submachine pistol using 50 or 75 round helical magazines. Magazine acts as cheekpiece in stocked variant, Light/camera module mounts above barrel. Limited deployment to specific police agencies.
s} BC-02: Highly suppressed straight-pull gun. Superior stealth for short-range sniping. 10rd detachable rotating magazine. The operating handle is designed to operate from the forward hand, meaning the shooter never has to adjust the grip on his trigger hand

6.5x45mm (long 6): Cased rifle cartridge accurate to 700 meters. Light machine gun and assault round, fair armor performance. Tracer, AP, and ball rounds
  AR-109: Standard infantry issue, 40-54cm suppressed barrel. Semi/burst rifle using 30 round box magazines. Underbarrel shotgun or grenade mount with integral secondary selector. Optics and bipod may be fitted, along with heavy barrel, for designated marksmen.
  AR-109s: Light sniper rifle, semi only. Commonly found with police units, due to lower collateral damage and noise. Accepts optics, suppressor, and bipod, often used with 10rd mags.
  AC-111: Bullpup , 40-54cm barrel, collapsible stock. Underbarrel secondaries limited or impossible, but tasers are available. Popular for urban warfare and police use.
  MR-109: Squad LMG variant. Can use linked rounds or standard box mags. Closed bolt, forced air cooling through handguard. Vertical forward grip contains bipod. Cermet-finned 54cm barrel

8x60mm: Sniper and Medium machine gun round. Good armor capability. Tracer, AP, expanding and solid ball
  BR-207: Standard sniper rifle, bolt action. 5rd box mag, can accept 25rd. Removable suppressor and bipod, no accessory rail. Accepts various optics, standard is 6-12X w/night adaptor. Derived from the AR-202
  AR-202: Semi-auto battle rifle, 25rd box magazine, integrally suppressed 62cm barrel. Secondary selector for underbarrel accessories. Bipod and scope for sniper/spotter.
  AC-202: Shortened AR-202, select-fire, collapsible buttstock. 52cm suppressed barrel. Usually issued to heavy infantry as close defense weapon.
  MR-206: Medium machine gun. 200rd links or standard box mags. Closed/Open bolt system switches automatically during sustained fire. Forearm folds down as bipod. Optics capable. Removable barrel.

12.5x100mm: Heavy machine gun and Sniper round. Excellent armor performance and range. Tracer, AP, HE, API, ST, and Ball
  BR-302: Straight-pull bolt rifle. 5rd box magazine. Suppressor/Brake keeps muzzle blast down, but noise and recoil are still stiff. ST ammo extends accurate range by 35% with laser spotter.
  AR-306: Heavy sniper rifle, 10rd box mag. A higher firing rate and capacity than the 302; slightly less accurate and a bit heavier. Most often deployed in pairs for anti-material missions.

15mm: Anti-Material caseless round. The absolute limit for individual weapons useable by unaugmented humans. AP, HEAP, API
  BR-325: Heavy bolt action sniper cannon with 4rd pre-loaded magazines. Shock absorbers in the buttstock and a serious muzzle brake do just enough to tame this beast. Only the toughest and most determined operators field this gun without mecha assistance.

18.5mm Shotshell: 72/82mm. Buckshot, Slugs, Doorbuster, and Beanbag rounds all cycle through these weapons. Specialty loads abound.
  PS-12: Pump shotgun available in various lengths and stock types for police and military forces. Light and tough, a perrennial favorite adapted from hunting arms.
  AS-17: Auto shotgun with mag tube above the barrel. Empty shells eject straight down and fresh rounds are easily indexed into the weapon with minimal manipulation. Low boreline helps straighten recoil for extremely quick shots on target.
  AS-19: Magazine-fed auto. The tracked helical magazine and offset grip make this a weapon for righties only, but the 25rd capacity more than makes up for any shortcomings. Fully depressing the trigger opens automatic fire at five rounds per second.
  XS-02: Underbarrel mounted pump gun for secondary fire. Two magazine tubes above the barrel give compact ammo capacity, and interchangeable trigger blocks allow seamless integration with various arms. Charging cycle is forward-back, and it can be seperately stocked to be a compact stand-alone weapon.

25x50mm Grenade: Frag/AirBurst, HEDP, and HEAP rounds all make this a favorite among soldiers. Specialty rounds are also prolific.
  AG-21: Styled after the AS-19, this assault cannon can lay waste to anything in it's path. Capable of bringing down medium and light power armor, 20rd mags give it plenty of stamina for firefights.
  XG-03: A beefier version of its shotgun brother; this weapon also mounts to any appropriate arm, or can be used on its own.

40x50mm Grenade: HEDP, HEAP, and numerous signal or specialty rounds ensure the longevity of this system. A large bore and steep trajectory limit ammo capacity and range. Good for riot gas and police use.
  XG-01: A single shot tube that is light under any weapon. Can be used independantly by attaching a stock.
  XG-02: A 3rd tube magazine allows quicker reloads for this pump launcher, but the size and weight can be troublesome in tight quarters. Also useable as a separate piece.

Notes on weapons: Most of the devices mentioned above may be readily imaginable by those familiar with firearms. One would hardly think that revolvers and automatic pistols are new to anyone who ever watched television. Shotguns are also generally recognizeable in their various forms, as are basic battlefield and hunting rifles. A few of these fictional weapons do take their form or inspiration from real, but obscure, platforms.
 The helical magazine is a radical concept best applied to pistol-length cartridges. It is most often credited to the Calico family of weapons, which are popular in movies for their odd and futuristic look; sometimes presented as laser guns without further modification, they are that unusual. I happen to have a photo of the 9mm carbine in my portfolio, with a small stock modification done by me. Helical mags do not lend themselves easily to rifle cartridges simply because the rounds must move forward one cartridge length for each revolution of the magazine. A longer round means a larger diameter magazine to ensure reliability in the ramp angle; too shallow of a spiral will not let rounds move forward with any sort of surety. These magazines are more manufacture and design intensive, so adaptation to other calibers is not readily undertaken. Box magazines can often be adapted for similar-length calibers by merely opening or closing the feed lips at the top. In the case of .308 - .243, it is simply the bullet diameter that changes; the same magazines may be used by both cartridges.
 The XS-02 and XG-03 are based loosely on both the Neostead and RMB-93 shotguns. I am currently developing a prototype for this device in 20 gauge. The trigger system is borrowed from the SCAR rifle accessories from Fabrique Nationale.
  The AG-21 and AS-19 are an improvement based on the Neopup PAW-20 assault cannon. This real weapon fires 20mm grenades from a limited 7 round magazine; I saw a need and method to improve the firepower by adapting the helical magazine concept to a non-circular profile
 While I believe the flattened helical magazine is a viable concept, the weight and size are still enough that it is of little benefit for most rifle cartridges, this concept is my own and really shines when applied to small rifle grenades or large shotshells. In the case of the AS-19, a 25 round magazine would allow a solid five seconds of automatic fire; surely it seems longer to those on the receiving end of a barrage.