I've found load data for external ballistics.
Technical Information
Sectional Density:0.110
Ballistic Coefficient:0.185
D: It has the velocity of 300 yards.
Ergo, 100 yards 2200fps, 200 yards 1800fps.
Looks like max. range is 300 yards, then it goes subsonic.
Not a big deal, since most engagements occur that close anyway.
Bullet drop 9" at 100 yards. If zero for 100 yards, and bullet drop is
21" at 200 and likely ridiculous at 300.
D: Hornady's 32 grain, .223 v-max.
Alternatively, a .17-.20cal VLD could be interesting to extend range to 300 yards.
Compare the H&K/FN 200 yard limit.
D: also I sadly would need to wildcat to find a cartridge after all. My pistol-grip shaped mag requires a straight-walled case. The easiest way is to 'improve' the .30 carbine with fireforming. I would hafta keep the pressure down to 9mm range to avoid extraction problems.
The Sporting Arms and Ammunition Manufacturing Institute (SAAMI) has set a pressure ceiling for standard pressure 9mm Para at 35,000 pounds per square inch (psi). By contrast, NATO pressure ceiling is 42,000 psi. In-between U.S. standard pressure 9mm and NATO spec, we have two options. 9mm +P has a SAAMI pressure ceiling of 38,500 psi
http://jdcomponents.com/loadinfo/30carbine/30carbine.html
Cartridge Data - .30 Carbine
Caliber - .308 IN
Bullet Weight - 55 GR
Barrel Length - 9.02 in
Case Capacity - 14.359 GR Of Water (CALC)
Bullet Diameter- .308 in
Sectional Density - .083
Volume Ratio - 12.6
Cartridge Tempreture - 70 Degrees F.
Powder Class - VERY FAST POWDERS
Powder Type - 2400, H-110, AA-#9 *Check Manual*
Charge/Bullet Weight - 0.209
Calc. Powder Charge - 11.5 GR
Load den - 80%
Est. Muzzle Velocity - 2300 FT/SEC
Est. Peak Pressure - 38500 PSI
D: that is a for a full-length barrel.
The suggested load info at the bottom is too optimistic since it relies on higher than standard pressures.
My latest low-ball estimage is 7 grain sabot, 32 grain bullet in ?.22cal at 2700fps muzzle velocity. It does the trick up close... but that is it.
D: the extra volume gained with a straighwall/sharper shoulder should be used to
a) lower pressure to 9mm non +P and
b) seat the sabot deeper.
The 32 grain is considered humane to take a 30 pound varmint at point blank. At range, this rapidly drops off.
This is where VLD microcalibers come in.
The MATCH VLD bullets are proving to be the most lethal big game hunting bullet available. (Watch Demo Clip) The VLD design incorporates a sharp nose that allows the bullet to penetrate up to 3 inches before it starts to expand. This delayed expansion results in a wound channel that is deep inside the vital area of any big game. After the bullet starts to expand it will shed 80% to 90% of its weight into the surrounding tissue traveling as deep as 18 inches. This results in a massive wound cavity that creates the greatest possible amount of tissue damage and hemraging within the vital area (organs). This massive and extensive wound cavity result in the animal dropping fast.
D: this leaves me in a quandary, as all PDW designs do.
1) dump energy in vitals but
2) make FBI 12" penetration rule.
with
3) a marginal manstopper that
4) is rapidly sub-hypervelocity which
5) is marginal to stop a man anyway.
All this to get through CRISAT armour with a sidearm.
I've discussed this with Phil West at
http://www.angelfire.com/art/enchanter/pdw.html.
Even at 2x the energy of competing PDW designs (not felt with a fast light bullet), his observations are still pretty accurate.
The NATO PDW requirements are, quite simply, harebrained.
There is a tiny niche for a weapon that is
1) a sidearm
2) to 100 yards
3) that beats CRISAT armour
that a 9mm/.45 cannot do well.
That is one tiny niche.
But using bursts of miniature rifle bullets to do so, thereby offsetting the larger mag ammo capacity seems a pretty troublesome way to do so.
I am designing this as a THOUGHT EXPERIMENT against the THOUGHTLESS NATO PDW requirements.
www.dtic.mil/ndia/smallarms/Marshall.pdf
D: here is a detailed breakdown of varioius requirements by nation and year.
The most recent specs are:
1) 3kg
2) < 1/2m long
3) beat CRISAT to 150m.
D: Phil says use a rifle carbine.
E.g. 13.5" M4?
D: many new ammo designs plan to address how marginal the 5.56mm is in less than a 20" or even a 18" barrel.
The problem is that the hypervelocity aspect of wounding rapidly disappears in a short barrel. The 6.5mm MPC and the 6.8mm SPC both address this with wider, heavier and slower bullets.
http://www.securityarms.com/20010315/galleryfiles/2400/2435.htm
D; here is a Floro 5.56mm PDW.
< 1/2m, weight is < 3kg.
D: here is the XM8 with 9" barrel:
2401 fps (732 mps) with 9.0 in. barrel
http://www.chuckhawks.com/replacing_5-56mm.htm
The 5.56mm cartridge is very efficient at wounding tissue at short range because light, high velocity bullets have a tendency to destabilize in tissue, making for wounds that may seem out of proportion to their caliber, but of course your mileage may vary.
D: but take away that velocity, and you have something only for squirrels.
D: so why build it? It still kicks the crap out of both the H&K and FN designs.
I think Phil is basically correct when he says PDWs are an expensive way to get users killed. But less so with mine.
A quad stacked magazine can *just* fit in a PDW pistol grip. These dimensions are based on the Glock .45GAP grip. The grip is wide at the rear like the .45ACP grip, but narrrower at the front like the .45GAP grip.
http://jdcomponents.com/loadinfo/30carbine/30carbine.html
This shows a tentative .223 sabot load. I found a Black Hawk pistol reloading page that claims http://hunting.about.com/od/guns/l/aastruger30bh.htm
that a 7 grain sabot with 40 grain .22cal bullet at 3000fps is reasonable. Recoil is 9mm -level. This load would wound as a hypervelocity round at normal combat ranges for a PDW. It would kick the snot out of H&K and FN. The cartridge width with a quad stacked mag means that the lower side mag is exposed to the outside, in effect forming part of the grip. The guide grooves fore and aft allow for adequate rigidity. The .30cal bore also allows more effective subsonic loads than other PDWs. The .30 bore also is less likely to plug with water. Use of a sabot allows focus on the bullet's external and terminal ballistics.
I am unsure if the head-seating of .30 carbine affects if a blowback can be used with it. The desire for high first-shot accuracy has led to the closed bolt MP7 arrangement being favoured over an open-bolt SMG blowback setup, despite the ease of manufacture of the blowback. This design is complementary with my hi-lo pressure chambered 12 gauge frag load idea.
Thoughts? The sole remaining M1 Carbine factory is closing, so the setup gear would be cheap! [=
