The OICW is supposed to have a 10 inch barrel, and in order to obtain a high enough velocity to get the rounds to fragment, they are using "hot" ammo right?

My question is what is the limiting factor that is preventing 5.56 from being used effectively in a handgun-sized weapon?  I know that there are 10mm rounds that are necked down to use 5.56mm bullets...so what is keeping these rounds from attaining rifle velocities?  

Can't you just use a faster burning powder?

Skinny bullets like the 5.56 have a small cross sectional area, not much there for combustion gasses to press on. So, to make up for that you must have high pressure to squirt them out the barrel. High pressures and fast powders are a formula for a barrel explosion. Thats why rifles use slower burning powders - so they can keep the pressures within reasonable limits. Since the powders burn slow this means you need a barrel longer than 10" so the powder has time to burn completely. Sorry but that the way it is...ECS

Couldn't stronger/reinforced barrels be produced to compensate for the increased pressure?

BTT

anybody?

dog,
I'm sure a pistol could be designed to fire the 5.56mm cartridge but I'm not sure where the market for such a weapon would be ??  There would have to be an explosion in the chamber resembling a small nuke to get enough mv........

I know that it would take a lot of force to make it happen, but if you could get the power of a rifle in a nice, neat, little package...I think it would be worth the extra weight(to a point) that would be required to secure the chamber from blowing up...right?

Higher pressure also means increasing the strength of the barrel and receiver.  That means making it thicker.  The peak pressure for 5.56mm is already over 50,000 psi's.  Switching to approximately 26 grains of much faster pistol powders in such a small case has to generate some real exciting pressures.  

Quoted: I know that it would take a lot of force to make it happen, but if you could get the power of a rifle in a nice, neat, little package...I think it would be worth the extra weight(to a point) that would be required to secure the chamber from blowing up...right?

I guess the reason I'm reluctant to embrace this idea is mostly due to the problems our front-line troops are having with the short barreled crap M16 variants in the Afghan.  There's not enough muzzle velocity for the round to penetrate and knock-down range seems to be about 60 yards.

(The 5.56mm round was designed for 18" barrel weapons generating over 3000 fps.)

That's what I am wondering, if it would be possible to get >3000 fps from a 4-5" barrel?

Quoted: That's what I am wondering, if it would be possible to get >3000 fps from a 4-5" barrel?

Possible yes but whether practical or not I just don't know enough to comment.

("Wadman" mentions......."some real exciting pressures.")

Does anybody know whether or not this would be practical?  Who would know something like this? (a metallurgist?)

It's probably possible.  

BUT - Remember that ammo is currently able to be shared between all rifles in a platoon.

If you create a new superhigh pressure 5.56, the only weapon that would be able to shoot it would be the one it was designed for.  If that rule was broken, we would have dead or maimed troops from their weapon acting as a hand grenade.

KISS

Quoted: That's what I am wondering, if it would be possible to get >3000 fps from a 4-5" barrel?

Hey, what happened to the 10" barrel?

Let's see; at least 3,000 feet/second from a 5" barrel with a .224 caliber projectile.  You'd be looking at a fat case holding a generous amount of some really fast burning powder (Alliant Bullseye?).  And the bullet would probably weigh a whole lot less than 55 grains.  Just a wild guess, I'd say pressures would push the proof load mark.  At least 70,000 psi's or higher?  I sure wouldn't want that thing going off in my hand.  

Arndog, are you familiar with the properties of progressive powder and its relation to pressure and velocity?

As far as being practical, there are a lot of wildcatters out there who constantly push the limits.  But even they haven't come up with what you're suggesting.  The closest is the .224 Boz and even that falls well short of your 3,000 feet/second mark.

Quoted: Does anybody know whether or not this would be practical?  Who would know something like this? (a metallurgist?)

brouhaha makes a good point.  From the military view, commonality of ammunition would make sense but, as "bro" points out there would be no commonality.  And with the same caliber ammo for two different weapons........bad stuff is gonna eventually happen.

To directly answer your question, I believe it would require a sophisticated firearms manufacturer to pull all the necessary disciplines (including metallurgy) together to design and manufacture such a pistol.

Sorry for all the referances to 5.56. I am talking about a new cartridge that would use a small, high velocity bullet, such as the m193's 55 grain bullet, but in a shortened cartridge(small enough to get your hand around the grip easily)...and avoiding the improper ammo mishaps.  Combining the deadly effects of fragmentation, with a small (but probably heavy) package.

Quoted: Quoted: That's what I am wondering, if it would be possible to get >3000 fps from a 4-5" barrel? Hey, what happened to the 10" barrel?

That was the OICW, I'm talking about something crazier than that.

Arndog, are you familiar with the properties of progressive powder and its relation to pressure and velocity?

Not very...why, does it show?

Progressive propellant is a whole different animal than black powder.  Whereas black powder is actually an explosive, modern progressive powder actually burns (it burns really fast but it still burns).  Black powder "explodes" at the same rate or velocity regardless of whether or not it's contained.  Progressive powder behaves much differently.  If you ignite a pile of prog. powder on the sidewalk, it'll smoke and burn a bright orangish red.  This could take a second or two.  But in the confines of a cartridge in a firearm chamber, it burns cleanly and without hardly any smoke (hence the term smokeless).

With black powder, the mechanism for driving the bullet is the force of the explosion.  But progressive powders push a bullet by very quickly generating large quantities of gas.  That expanding gas is what forces the bullet out the barrel.  To get the highest velocity for a given barrel length, you use a powder with a certain burn rate that will give you an increasing push until the bullet leaves the barrel.  

If the powder is too fast, it'll burn out long before the bullet leaves the barrel.  The bullet will slow down while still in the barrel.  If you use more of the fast powder, pressures could be unacceptably high.  The opposite is true with a slow powder.  Too slow and a lot of unburnt (and wasted) powder shoots out the barrel.  

So how do you push a bullet faster from a firearm using modern smokeless progressive burning propellant?  

The easiest is to make the bullet lighter.  Lighter bullets have less resistance so they're easier to push.  This helps keep pressure down too.  

The next easiest way is to make the barrel longer.  This allows you to have a longer duration of "push" from the expanding gases.  Of course there's a point of diminishing returns as the amount of gas that X grains of powder generates runs out.  

If those two methods aren't enough, you either have to increase the powder charge or use a powder with a different or faster burn rate.  This is the really fun part.  Basically you want more "push" in less time.  Since "push" is pressure, everything about the firearm will be affected.  To handle more pressure, either the materials have to be stronger or a lot thicker (and thicker means heavier and more bulky).  Also, more pressure means more recoil.  For a semi-automatic or fully automatic firearm, this also means the speed of the operating parts may be a lot faster, increasing wear and tear while reducing reliability.  

Thanks Wadman. I knew most of that except for the stuff about black powder.

Also couldn't you have an increased burn rate by altering the atmospheric enviroment in which the powder burns?  What would be the best enviroment for something to burn? 100% oxygen? or maybe compressed oxygen?

Maybe a shorted cartridge case with a 100% oxygen enviroment to work with?

Quoted: Also couldn't you have an increased burn rate by altering the atmospheric enviroment in which the powder burns?  What would be the best enviroment for something to burn? 100% oxygen? or maybe compressed oxygen?

Powder in a cartridge is already a closed environment.  If you stuck a handgun in a swimming pool and pulled the trigger, it'll definitely go bang at least once.  So there's more than enough oxygen inside for complete combustion.  Increasing the percentage to increase the burn rate will still get you the same result; higher pressure.  As far as I know, there's no way around higher pressure.  You want to push a bullet harder you'll need more pressure.  Now there are some powders with burn characteristics that may stretch out the peak pressure over a longer duration.  But they aren't getting 50% more velocity.  

So the big enemy is pressure.  If you want to push a bullet real fast but you don't want to give the powder time to work, you need to push it real hard from the start.  Even if you could get have a firearm made from some carbon-fiber/polymer that happened to be 15 times stronger than steel, and it could handle the pressure, you still have to fire the weapon!  A 30 ounce handgun pushing a 45 grain .224 bullet at 3,000 feet/second is going to generate a LOT of recoil.

Arndog,

I have to admit you've got me a little perplexed.  You state that you already knew a lot about progressive powder.  But you're still asking about why you can't just substitute faster burning pistol powder to get more velocity.  And then that last question about increasing the burn rate.  Getting more pressure is not the problem.  You can always get faster powder and/or more of it.  The problem still remains; How do you handle all that pressure?  

Quoted: Maybe a shorted cartridge case with a 100% oxygen enviroment to work with?

Gunpowder -- both nitro and black powder -- contain all the oxygen and ingredients necessary for combustion (or detonation in the case of black powder).  External oxygen is not necessary and replacing the air in the case with pure oxygen wouldn't make any practical difference in the burn rate or energy.  The powder is fully self-contained by its very composition.

did anyone ever notice the bayonet for that damn thing. now thats funny, can you imagine actually trying to wield that thing as an over grown spear. not to mention that it is pretty well usless as a rifle.

however I wouldn't mind having a light semi automatic grenade launcher in addition to and m4a1. but there is no way I would ever carry that peice of shit into combat.

ps. did anyone notice that the called the magazine a clip, if this is an official picture with official labels that just goes to show you what kinda remf's are really designing this junk.

hehe, I think that if they could make that stock bullet-proof that it would make one hell of a shield...

Quoted: ps. did anyone notice that the called the magazine a clip, if this is an official picture with official labels that just goes to show you what kinda remf's are really designing this junk.

I believe that image originated in "Popular Science" or "Popular Mechanics".

I believe that image originated in "Popular Science" or "Popular Mechanics".

that makes a little more sense yet you still have to admitt the guys who are designing this debacle are none the less just a bunch of techy remf's who don't know what it takes to make a propper battle weapon. what would happen if you had to go to ground, most people would probably be scared they would break the damn thing.

what the average grunt needs is a simple ,effective, accurate, and reliable weapon.

also remember when thinking of a weapon always think with the lowest common denominator in mind, meaning if the guy who's next to you isn't neccessarily the brightest bulb in the bunch he just might not be able to figure out some of the functions of this rifle. hell I have a hard enough time trying to progam my vcr so far this thing is really striking out in my book.

ps it says the the 20 barrel is titanium, I thought that titanium couldn't be rifled so if this barrel is titanium than is it not rifled ?

A 5" barrel that can shoot 3000 F/S is possible but it would take a new cartridge, bullet (3mm/17cal?) barrel and action (probably bolt action) and maybe new powder and exotic materials.

Building a reliable, portable, SA/FA, GI proof military weapon would a order of magnitude more dificult and hyper expensive just for the research.

Wouldn't it be easier to build a grenade launcher that fires some kind of flachett (sp.) or multiple sabot round as well as explosive stuff?

also remember when thinking of a weapon always think with the lowest common denominator in mind

Well, there is always the bayonet if you can't figure out the controls.

Av.

Anybody know the effective range of M193 and M855 from a 10" barrel?  Troy's FAQ only goes down to 11.5" barrels.

Quoted: Anybody know the effective range of M193 and M855 from a 10" barrel?  Troy's FAQ only goes down to 11.5" barrels.

What is the effective range with the 11.5" barrel ??

Quoted: What is the effective range with the 11.5" barrel ??

45m for the M193 and 15m for the M855.

Quoted: Quoted: What is the effective range with the 11.5" barrel ?? 45m for the M193 and 15m for the M855.

We're getting down to the range of a good pistol.....[Thanks !!]

actually blackpowder doesnt "explode" in open air unless you burn very large quantities or its a small grain (like 4fg) it "explodes" by burning really fast. however it burns fast wheather in the chamber of a gun or out in the air... so it appears to be "exploding" because it burns so fast... Some call it "deflagerating" (dont know how to spell the damm word). If you want something that really explodes thats what C-4 and rifle primers do. They detonate in a sense they burn so fast that it creates shockwave which progresses through the explosive... what you hear is a loud POP. If you pull the trigger on a primed brass (no bullet and powder) the pop you hear is the rifle primer detonating. Smokeless burns really slowly in the open and smells like crap (I like the smell of black powder better...) and leaves some nasty crap behind, but in the chamber of a gun it burns REALLY fast, faster than blackpowder even. So you can get smokeless powder to "explode" you just got to contain it, but then it would be very dangerous because when that container lets go more than 100 KPSI of pressure is released propelling peices of that container everywhere at a high speed...

I know the Military guys can't use HP or SP ammo, but you figure that would inprove knockdown and wounding power in a 5.56 out of a commando 10.5" barrel. Just a thought.

The UN and NATO restrict types of ammo used in the military.  I thought the OICW was designed for Urban Warfare?  Since it has a camera system on it to look around corners and the 10in  barrel.  Rumor is the US is testing for a new weapon to replace the M16.  OICW or M4, since wars a going Urban and CQB.