Real Boltgun: Entirely Possible.

[Grenadier]

Sometimes a sci-fi weapon isn't just a dream but something that could actually be done. We know there are powered exoskeletons being developed which enhance the wearer's strength. So it's not unreasonable to think that refining this technology and slapping armor on it could yield actual power armor not too far from now. The key will be developing a power source that it can carry on itself.

A goal of mine is to one day have a functional Space Marine bolter. If ever I had the 50 grand or so needed to hire a gunsmith to take on this project that is.

What we know about the bolter: it's gun that fires rockets instead of bullets. Rockets which can have several kinds of warheads. It appears to be a short to medium range weapon and semi to full automatic. And its rounds are 75 caliber. (Remembered reading that somewhere.

Reality:

There were guns that actually did fire rockets. A company named MB Associates made a family of rocket firing guns back in the 1960's. They were named "Gyrojet." They developed a pistol, rifle, and carbine version. And the rounds were intended to be armor piercing.But Gyrojets were plagued with problems. Especially with their cooling vents and ammunition. Sometimes the rounds didn't fire the first time. And they were not very accurate. This is because a regular bullet while inside the barrel has the necessary speed to begin spinning with the rifling. Rockets inside the barrel lacked the speed necessary to get the spin going. Gyrojets were also very slow to load. The rounds originally were designed to be 51 caliber but they ended up with several ranges of caliber.

It seems at one time civilians were able to get Gyrojet guns. And it also seems some of the pistol variants were used in the Vietnam War. Now they're very rare collectible guns which are seldom ever actually fired since it's virtually impossible to obtain ammo, and if you can find it the rounds are more than 100 dollars each.

The key difference between rocket ammunition and traditional ammunition is simple: a bullet reaches it maximum speed inside the barrel but the speed drops off afterwards. Thus a bullet's maximum kinetic energy is always at point blank range. Rocket ammunition, however, is the exact opposite. It's maximum speed is reached long after it exits the barrel because it continues to accelerate. It'll do so until its fuel is used up. And so the maximum kinetic energy of rocket ammunition is reached when the propellent burns out.

Basically this means a bullet at long distances will not hit with full force whereas a rocket round will.

There is a drawback though to rocket ammunition: at short ranges its maximum kinetic energy is less than it would be at long range. So in theory if you're firing rockets at a target it behooves you to be far from it. This would suggest such ammunition is not as good as bullets in close in shooting.

However this can be overcome. Since rockets need a bit of "running room" to reach their full potential the solution is to give them a "boost." I would think a better round is a hybrid of both rocket and traditional ammo. A two stage kind of thing. The first stage is a small amount of powder to get the rocket up to speed inside the barrel which will also allow it to pick up the initial speed it needs for the stabilization provided by the rifling inside the barrel. The second stage engages almost as soon as the powder is ignited. While inside the barrel the rocket propellent begins to burn, having been assisted by the traditional gunpowder. It would, of course, be tricky to find a way to keep the explosive powder from entirely burning out the rocket propellent inside the barrel.

Tests of the Gyrojet did reveal some interesting data on the rocket ammunition. At 1250 feet per second the rocket had more energy than 45 ACP ammunition. Tests also revealed they had greater than previously calculated effect at closer ranges but still were most effective at long range. Perhaps the hybrid ammunition could make the rocket round effective at all ranges.

And if one were to incorporate smart bullet technologies which weren't available in the 60s. These use compact electronics in the form of inertial measurement units. Smart bullets today apparently are still in development but it looks promising.

Clearly rocket ammunition would be very expensive. But the rifle or pistol that fires it need not be. We think of the Space Marine bolter, bolt pistol, or heavy bolter as big, clunky, and very heavy guns. But rocket firing guns actually would be lighter than traditional guns. Because they will not need the heavy barrels which must withstand the tremendous forces going on inside.

Overall, if you had the desire and the money to hire a gunsmith with the talent to develop one you could indeed have a bolter today.

[Lord Tothe]

I don't know how well that would really work. Aren't bolters designed to be used by 750 lb, 7-foot-tall genetically engineered super-soldiers in futuristic armor?

On the practical side, I know there have been experiments in 12 ga. grenade launcher shells. A 3-1/2" magnum pushing a small rocket weighing around 3-5 oz. night be workable, but the ammo would be prohibitively expensive.

[TheWildRider]

The Deathwind Project are actually attempting to resurrect the gyrojet project, but I'm not sure you could get them to produce .75 caliber high-explosive rounds for your poorly designed boltgun.

There's a reason none of today's firearms are that boxy :L

[Lord Tothe]

A more practical idea: The .50 BMG round is basically an up-scaled .30-06. Create a new cartridge that scales the dimensions of the .30 WSM by a factor of 2.5 and design a bullpup rifle with an integral suppressor. You still probably need to be a sci-fi super soldier to handle it, but it's slightly more feasible than trying to recreate a fictional weapon.

*edit* Da boyz sed da best wepun evar wuz da rokkit-propelled chainsaw.

[Slug]

[URL="http://www.youtube.com/watch?v=aJYMtgsSl5k&feature=fvsr"]http://www.youtube.com/watch?v=aJYMtgsSl5k&feature=fvsr[/URL] jump to 4:30

Essentially what you are after, or at least as close as we can get for our abilities.

Though to be fair a few navies are testing various rail guns which have a huge potential for a variety of military and non military purposes. [URL="http://www.howstuffworks.com/rail-gun.htm"]http://www.howstuffworks.com/rail-gun.htm[/URL]

[pathwinder14]

The Deathwind Project are actually attempting to resurrect the gyrojet project, but I'm not sure you could get them to produce .75 caliber high-explosive rounds for your poorly designed boltgun...L

Glad to see someone already mentioned it.

[Forrix]

Your deffinately correct in that we have the ability and even HAD the ability to make a "bolter". The real question is why? Seems like most of what you hear about it is that other then a undeniable cool factor a gun that shoots tiny missiles is really not better in anyway then rifle or if you need explosive power any of the rapid fire grenade launchers around. You can bet that if there was a niche or a use for it the military would have already made it turns out humans place killing each other pretty high on the to do list.

[Grenadier]

I'm not suggesting it would actually be practical or fulfill a combat role that sorely needs to be fulfilled. Creation of one would just be for pure fun and the sake of doing it.

Since a bolter's rocket rounds are explosive and rocket rounds would lend themselves to light armor piercing it could perhaps serve a light ant-armor role. But the military already has plenty of ways to deal with that. Such as the Barrett 50 caliber rifle.

With fragmentation warheads it would work great against infantry. But the military already has an abundance of ways to cut down infantry.

Essentially a real bolter would just be a whole lot of firepower in the hands of one trooper but it would not be necessary.

I'm only thinking it'd just be fun to make one.

[Duskstorm]

Anyone in their right mind would love to have an actual Boltgun kicking around, well, in my world they would anyway lol!

[entendre_entendre]

You want to know what an infantry capable bolter would act like? Here, DICE solved that problem for you:
[url]http://www.youtube.com/watch?v=zesdXj0oLQQ[/url]

Compare to Firewarrior's representation (the closest to the fluff in the games so far):
[url]http://www.youtube.com/watch?v=A4BD8uiTUGw[/url]

Pretty similar huh?