Personal Defense Weapons vs. SMGs
- Thread starter Jame
- Start date
Father Fletch
SOC-12
The submachine gun was a child of the late 19th century and world war one that used pistol caliber ammunition combined with a high rate of fire to produce a relatively light weapon capable of shock effect in close combat, as found in the trenches of Europe. Its relative light weight, short length, ammunition capacity, volume of fire and good handling characteristics, when compared to service rifles of the day, kept it in use and development during the interwar years. Once world war two broke out the SMG was once again pressed into service with troops the world over who wanted high volumes of fire contained in handy packages.
It was during the end of WW2 that the successor to the SMG, the assault rifle, was born. With ancestors on all sides and dating back to the teens and twenties in some cases, the assault rifle fired an intermediate cartridge (between a pistol sized and rifle sized) on automatic, from a longer barrel, but with the SMG’s detachable magazine. This was considered the wave of the future; better ballistic performance than a pistol round, better package size than a traditional service rifle.
The SMG began to be relegated more to the rear area defense/special operations/police/dynamic entry role in the 40 years after WW2. It was then determined that aircrew who had been shot down were at a disadvantage when in enemy held territory. This came out of the Allied and American experience in Vietnam and Korea, where POWs were a highly visible political shuttlecock. The high rate of fire, even smaller package and (relative) higher power pistol ammunition that a SMG could fire was desired in a weapon which aircrew and vehicle crews could carry comfortably gave rise to the PDW (Personal Defense Weapon). The concept was in-between a Full sized SMG (8-10 lbs, 2 feet long) and a pistol (2 lbs. ½ foot in length). The slightly heavier action a PDW could mount, with a “long pistol” length barrel, a slide out or fold down stock all came together to make another intermediate sized weapon (3-5 lbs. 1-1 ½ feet). Its usefulness has yet to be proven, and its size seems more of use to a bodyguard who needs discreet firepower of this nature to protect his principal.
I hope this helps
It was during the end of WW2 that the successor to the SMG, the assault rifle, was born. With ancestors on all sides and dating back to the teens and twenties in some cases, the assault rifle fired an intermediate cartridge (between a pistol sized and rifle sized) on automatic, from a longer barrel, but with the SMG’s detachable magazine. This was considered the wave of the future; better ballistic performance than a pistol round, better package size than a traditional service rifle.
The SMG began to be relegated more to the rear area defense/special operations/police/dynamic entry role in the 40 years after WW2. It was then determined that aircrew who had been shot down were at a disadvantage when in enemy held territory. This came out of the Allied and American experience in Vietnam and Korea, where POWs were a highly visible political shuttlecock. The high rate of fire, even smaller package and (relative) higher power pistol ammunition that a SMG could fire was desired in a weapon which aircrew and vehicle crews could carry comfortably gave rise to the PDW (Personal Defense Weapon). The concept was in-between a Full sized SMG (8-10 lbs, 2 feet long) and a pistol (2 lbs. ½ foot in length). The slightly heavier action a PDW could mount, with a “long pistol” length barrel, a slide out or fold down stock all came together to make another intermediate sized weapon (3-5 lbs. 1-1 ½ feet). Its usefulness has yet to be proven, and its size seems more of use to a bodyguard who needs discreet firepower of this nature to protect his principal.
I hope this helps
There are two weapons which are currently marketed as PDWs. Both companies call these weapons sub-machineguns (machinen pistole in German). FN even makes a pistol that fires the 5.7x28mm
The FN P-90 PDW (which Fabrique National calls a SMG)
http://www.fnmfg.com/products/p90/p90.htm
Technical Data:
Operation: Blowback mechanism firing from closed breech
Weight with Loaded Magazine: 6.6 lbs.
Magazine Capacity: 50 rds
Firing Modes: Single shot, full automatic
Cyclic Rate of Fire: 900 rpm
Maximum Effective Range: 200m
SS190 Ammunition:
Caliber: 5.7mm
Weight: 93 grains
Projectile Weight: 31 grains
Recoil Impulse: 0.44 lb/s
Muzzle Velocity: 2,346 fps
Perforation at 200m: Body Armor
>48 plies of Kevlar
HK PDW MP7
http://www.hkpro.com/pdw.htm
PDW Technical Specifications
Overall Length: 13.38 in./ 340mm (stock closed) 21.19 in./ 541mm (stock open)
Barrel Length: 7.09 in. 180mm
Width: 1.89 in. 48mm
Height: 6.77 in. 172mm
Unloaded wt. (20 rnd. mag): 2.64 lb. 1.20 kg
Loaded with 20 rounds: 2.86 lb. 1.30 kg
Loaded with 40 rounds: 3.39 lb. 1.54 kg
4.6 x 30 Ammunition Technical Specifications
Cartridge Length: 1.5 in. 38mm
Projectile weight: 24.7 grains 1.6 g
Case length: 1.18 in. 30mm
Ballistics/Velocity: 2379 fps 725 m/sec
Ballistics/Muzzle Energy: 312 ft/lb 420 joule
Projectile composition: Copper plated solid steel bulle
The FN P-90 PDW (which Fabrique National calls a SMG)
http://www.fnmfg.com/products/p90/p90.htm
Technical Data:
Operation: Blowback mechanism firing from closed breech
Weight with Loaded Magazine: 6.6 lbs.
Magazine Capacity: 50 rds
Firing Modes: Single shot, full automatic
Cyclic Rate of Fire: 900 rpm
Maximum Effective Range: 200m
SS190 Ammunition:
Caliber: 5.7mm
Weight: 93 grains
Projectile Weight: 31 grains
Recoil Impulse: 0.44 lb/s
Muzzle Velocity: 2,346 fps
Perforation at 200m: Body Armor
>48 plies of Kevlar
HK PDW MP7
http://www.hkpro.com/pdw.htm
PDW Technical Specifications
Overall Length: 13.38 in./ 340mm (stock closed) 21.19 in./ 541mm (stock open)
Barrel Length: 7.09 in. 180mm
Width: 1.89 in. 48mm
Height: 6.77 in. 172mm
Unloaded wt. (20 rnd. mag): 2.64 lb. 1.20 kg
Loaded with 20 rounds: 2.86 lb. 1.30 kg
Loaded with 40 rounds: 3.39 lb. 1.54 kg
4.6 x 30 Ammunition Technical Specifications
Cartridge Length: 1.5 in. 38mm
Projectile weight: 24.7 grains 1.6 g
Case length: 1.18 in. 30mm
Ballistics/Velocity: 2379 fps 725 m/sec
Ballistics/Muzzle Energy: 312 ft/lb 420 joule
Projectile composition: Copper plated solid steel bulle
Father Fletch
SOC-12
So give us the stats for T20...huh huh huh...c'mon! 
Jame, the PDW is a lower calibre (5.6/5.7mm) weapon than most SMGs (9-10mm) It fires a more powerful cartridge and a lighter bullet so muzzle velocity is higher, allowing longer engagement ranges and better armour penetration than either a pistol or SMG. It's most of an assault rifle in a package smaller and handier than most SMGs (HKMP5K being an exception). In T20, It'll be a two dice weapon on single shot possibly D8s, and can fire bursts and auto to get extra dice. It has the potential for a bigger mag than pistols and SMGs because the rounds are narrower. Range? Well I don't know because they're all messed up in T20 anyway. Twice SMG range seems about right.
It might even warrant having AP ammo as standard (since that's one of its design aims), or maybe it's just an SMG with AP ammo... :/
It might even warrant having AP ammo as standard (since that's one of its design aims), or maybe it's just an SMG with AP ammo... :/
As a generic PDW I am taking a design closer to the MP-7 than the P90
TL8
Weight: 1500 g
Ammo: 350 g (45 rd magazine)
Price: 400 Cr/30 Cr magazine
Dexmods 6 or less -1, 8+ +2
Striker
Effective 5(3) +3
Long range 10(2) +2
Extreme 20(1) +1
(i.e at out to 50 meters there is +3 to penetrate armor and full asuto fire adds +3 to the die roll)
CT
Close range -2/-2
Short range +1/+3
Medium range 0/+3
Long range -4/-1
Extreme rng -6/-5
Damage 3D
No Armor +2/+5
Jack +2/+5
Mesh -1/+2
Cloth -3/-1
Reflec +2/+5
Ablat +0/+2
Battle -5/-4
As I was afraid, I can't find my TNE book.
TL8
Weight: 1500 g
Ammo: 350 g (45 rd magazine)
Price: 400 Cr/30 Cr magazine
Dexmods 6 or less -1, 8+ +2
Striker
Effective 5(3) +3
Long range 10(2) +2
Extreme 20(1) +1
(i.e at out to 50 meters there is +3 to penetrate armor and full asuto fire adds +3 to the die roll)
CT
Close range -2/-2
Short range +1/+3
Medium range 0/+3
Long range -4/-1
Extreme rng -6/-5
Damage 3D
No Armor +2/+5
Jack +2/+5
Mesh -1/+2
Cloth -3/-1
Reflec +2/+5
Ablat +0/+2
Battle -5/-4
As I was afraid, I can't find my TNE book.
The factor you are looking for is pounds per square inch. Two bullets of different sizes with the same powder charge strike a target. The larger bullet will disperse more of its power in the initial hit due to the larger surface area, this dispersing of the power results in less power to penetrate. The smaller bullet looses less energy on the initial impact and carries it through. Plus with the smaller surface area the impact is greater to that smaller area, assuming same mass.
Like driving a finishing nail through a board and a railroad spike, hit them the same and see which one sticks.
The difference is often stopping power v penetration. The larger caliber of bullet will cause more damage (assuming the bullet doesn’t tumble) but with less penetration. The smaller caliber of bullet will cause less damage (assuming again no tumble) but will have greater penetration.
The hollow-point bullet is a way to maximize bullet surface area after impact to increase the size of the wound, and thus the damage caused to the target. The problem is, this greater surface area (and the softness required in the bullet) reduce the overall penetration power of the bullet. This is why in most systems hollow-points do less damage to armor and more to unarmored targets. While armor piercing rounds normally do less damage overall, they are designed not to loose their initial shape.
Same powder smaller bullet = more penetration/less damage
Same powder larger bullet = more damage/less penetration
AP rounds are solid shell or core, or what have you based on TL of the bullet, designed to perform differently then a soft bullet of the same type. Thus, many of the comparisons of larger v smaller bullet in the above can be changed due to the overall composition of the bullet itself. So in the above examples assume two identical (in their design and material make-up), non-piercing, bullets of differing caliber (size) and fired from similar weapons.
Hope that helps some, kinda rushed today and didn't have a lot of time to work on the wording.
-Torn
Like driving a finishing nail through a board and a railroad spike, hit them the same and see which one sticks.
The difference is often stopping power v penetration. The larger caliber of bullet will cause more damage (assuming the bullet doesn’t tumble) but with less penetration. The smaller caliber of bullet will cause less damage (assuming again no tumble) but will have greater penetration.
The hollow-point bullet is a way to maximize bullet surface area after impact to increase the size of the wound, and thus the damage caused to the target. The problem is, this greater surface area (and the softness required in the bullet) reduce the overall penetration power of the bullet. This is why in most systems hollow-points do less damage to armor and more to unarmored targets. While armor piercing rounds normally do less damage overall, they are designed not to loose their initial shape.
Same powder smaller bullet = more penetration/less damage
Same powder larger bullet = more damage/less penetration
AP rounds are solid shell or core, or what have you based on TL of the bullet, designed to perform differently then a soft bullet of the same type. Thus, many of the comparisons of larger v smaller bullet in the above can be changed due to the overall composition of the bullet itself. So in the above examples assume two identical (in their design and material make-up), non-piercing, bullets of differing caliber (size) and fired from similar weapons.
Hope that helps some, kinda rushed today and didn't have a lot of time to work on the wording.
-Torn
I concur.
Generally speaking, penetrating armor is porportional to cross-sectional energy, that is why an ice pick pentrates better than a hammer. A 5.56 from a M16 has about the same enery (1700 J) as a 7.62mm round from an AK but defeats much more armor (both with ball ammo). This is also how APDS works.
The bigger the hole, the more damage. 9-10mm pistol balls obviously makes bigger holes than a 5-7mm pistol. But a pointy 5-7mm rifle bullet is unstable in "wet" materials and tumbles and a 25mm long bullet going sideways makes the bigest hole. (I am simplifying and ignoring expandig bullets like hollow points, fragmenting bullets like the 5.56, and the over-rated "hydrostatic shock")
Blunt bullets don't tumble and follow a straighter line through the target, better for finding the heart of big game. Penetrating deeply in wet materials (water, geletin, animals) depends on momentum. Big game rifles tend to fire long, heavy, blunt bullets, whether they are 6.5mm Manlicher or .600 Nitro express. (Bigger is better? Guess which has killed more elephants.)
Generally speaking, penetrating armor is porportional to cross-sectional energy, that is why an ice pick pentrates better than a hammer. A 5.56 from a M16 has about the same enery (1700 J) as a 7.62mm round from an AK but defeats much more armor (both with ball ammo). This is also how APDS works.
The bigger the hole, the more damage. 9-10mm pistol balls obviously makes bigger holes than a 5-7mm pistol. But a pointy 5-7mm rifle bullet is unstable in "wet" materials and tumbles and a 25mm long bullet going sideways makes the bigest hole. (I am simplifying and ignoring expandig bullets like hollow points, fragmenting bullets like the 5.56, and the over-rated "hydrostatic shock")
Blunt bullets don't tumble and follow a straighter line through the target, better for finding the heart of big game. Penetrating deeply in wet materials (water, geletin, animals) depends on momentum. Big game rifles tend to fire long, heavy, blunt bullets, whether they are 6.5mm Manlicher or .600 Nitro express. (Bigger is better? Guess which has killed more elephants.)
I understand that because of the rise of personal armor, SMGs are being dropped in favor of carbine versions of assault rifles due to the increased penetration of the latter. For example, the M-4 carbine version of the M-16 is replacing the MP-5 family of SMGs in the US inventory.
As far as game mechanics go, I would rather use a needler, especially on any orbital station or starship. All I wanna do is kill/ incap a target, not rupture the bulkhead in a compartment. A hull cant be too thick, or all of the harmful stellar radiation gets broken down into more harmful radiations.
An example is that a relatively harmless gamma ray, when introduced to any sort of impedance-- like a bulkhead--, breaks down into harmless alpha particles and very lethal x-rays.
A thick bulkhead is therefore dangerous. A thinner bulkhead will allow a gamma ray to pass through, being relatively safe for an occupant. Any slug thrower is bad in such an environment-- as exposure to a hard vacuum would be undesirable at best.
An example is that a relatively harmless gamma ray, when introduced to any sort of impedance-- like a bulkhead--, breaks down into harmless alpha particles and very lethal x-rays.
A thick bulkhead is therefore dangerous. A thinner bulkhead will allow a gamma ray to pass through, being relatively safe for an occupant. Any slug thrower is bad in such an environment-- as exposure to a hard vacuum would be undesirable at best.
Actually, you can't simply use a thin barrier for long-haul ships, you need enough shielding to stop the radiation, which realistically means _really_ thick hulls (think meters of concrete). Traveller apparently has magic radiation blocking.
Shooting heavy weapons indoors a ship isn't a great idea, but in no version of Traveller (except maybe T20) will an assault rifle penetrate a normal hull.
Shooting heavy weapons indoors a ship isn't a great idea, but in no version of Traveller (except maybe T20) will an assault rifle penetrate a normal hull.
Unfortunately radiation in space is severe enough that even without a cascade from a moderately heavy hull you can't stay out for long. And useful equipment like EC/LSS, computers, elevators, etc will cause substantial cascade radiation. The Stanford Torus design used 4.5 tons/m2 of mass shielding to reduce radiation to 0.5 rem/year at the LaGrange point.
Space Settlements: A Design Study, Ch 4
According to Striker an Armor 0 starship hull is equivilent to "Armor 60", which is equivalent to 47 cm of TL A crystal iron (4.7 tons/m2, very close to the Stanford study). 5 cm of crystal iron will stop a FGMP-15.
Space Settlements: A Design Study, Ch 4
According to Striker an Armor 0 starship hull is equivilent to "Armor 60", which is equivalent to 47 cm of TL A crystal iron (4.7 tons/m2, very close to the Stanford study). 5 cm of crystal iron will stop a FGMP-15.
Hmmm ...
Newbie Marine: "So we can fire our high-energy weapons inside ships?"
Gunny: "No! You friggin' moron! Internal bulkheads are only vacuum rated, so you'll go straight through a whole pile of them, and dividing walls are even thinner!"
Newbie Marine: "So that's why we have these funny knives?"
Gunny: "Give me that cutlass and I'll show you why we have them!"
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