You folks seem to be on or at least very near the cutting edge of the accuracy challenge so here's a question for you. We're all aware of what the Abrams tank main gun can do, and I'm wondering why not do it on a smaller scale. Perhaps a brass 10 or 12 ga. shell and sabot with a 5.56-6 mm dart of some metal with sufficient thermal strength, perhaps in the 200 gr weight range. Big piston, small projectile. I'm guessing 70-75 kpsi. Would 6000 fps be unreasonable?
A gentleman who is knowledgable in the field of firearms suggested a Universal receiver set up, or a Hotchkiss Receiver for R&D. At any rate, I'm not a total nutcase, and I got all the humor I need out of a similar post in another forum. If anybody has any sincere and useful input on any aspect of this idea, I'm all ears. Thanks.
Now you should figure how to hold a 25 grain 17 caliber bullet in that hull, and arrange for a suitable rifle to be built - I bet you could make some serious money from that tv show where you send in home-videos!!! You might be able to get some 2000 yard kills on elk with that little pill! Perhaps Bullseye would be another powder to consider.
Since we are talking about the sublime, I will relate a true story about "extreme-reloading". When I was with our game agency I had the opportunity to develope a four-barreled net-firing gun that we used from helicopters for capturing deer-sized critters (and sometimes elk and caribou). The original idea had come over from New Zealand, we simply borrowed a couple of guns that other agencies had imported and tried to make one that was better. The basic unit had a heavy bolt action (P-14 or 98 mauser) with a short barrel stub (we did two, a .303 British and a .308 Win) that had a cone-shaped manifold screwed and welded onto it. There were four stainless-steel 3/4" pipes (barrels) angling out of the cone, making a sort of square, the barrels were about 18" long.
We had a heavy aluminum stock machined for the guns, complete with an automobile shock absorber built-in to help handle recoil. It had a pistol grip and a front grip for your left hand that stuck out from the forend - actually a handle from a motorcyle. This sucker was heavy - maybe twenty pounds loaded.
We custom built special fiberglass boxes that nestled into the four barrels, they had heavy canvas front flaps that stayed shut with velcro and were held in place with small bungee cords. We took 20 foot square pieces of cargo net and tied heavy twine to each corner, then attached a fairly heavy steel cylinder about 3/4" by 6 or 8 inches to each corner rope. The steel cylinders were close to the same diameter as the barrels, they actually had rubber "O" rings on them to make a snug fit in the barrel.
We simply tucked the body of the net into the fiberglass basket, locked the basket in place between the four barrels and pushed each weight cylinder down the appropriate barrel with a piece of wooden dowel - the ropes at each corner of the net were long enough to accomodate the cylinders going down the barrels.
When fired the four projectiles would fly out angling to the four corners of a square, taking the corners of the net with them. The velcro flap would burst open and the net would fly out as it was pulled by the cylinders. If the chopper was the correct height above the ground - as in VERY low, the net deployed like a parachute and tangled the critter. Obviously the critter was running like a raped-ape so shooting was somewhat tricky. The gun was used on the tv show WILD KINGDOM but that is another story.
Now comes the interesting part. I would take a new un-primed .303 or .308 cartridge case depending on the gun, and fill it with the fasted pistol or shotgun powder that we could find - Win. 231 comes to mind, been a while since I did this. To get the maximum amount of powder into the case I pounded (compressed) the powder with a hammer and a wooden dowel, then added more and repeated. When the case was almost full I put a chunk of paper towel in the neck and pounded it down to make a plug. Even smeared some wax on the outer surface of the paper to try to keep out moisture. When the plug was in place I then used a Lee hand primer to seat a primer and went on to crafting the next "load". We never fired very many shots and case life was amazing - could use the same cases many times as all that gas dumped into the manifold and was split four ways.
Shoulder firing the net-gun was quite an experience. I recall arranging (as in suckering...) one warden acquaintance to "test-fire the gun" for a group of game wardens in a parking lot during a meeting. He was going to shoulder-fire it horizontally, and chose not to take my suggestion to hold on "real tight". At the shot he was hurled backward, his eye-glasses sort of hung in the air for a split-second where he had been standing - then fell to the ground, and he was thrown backward several paces completely out of control. He slammed backward onto the hood of my new Ford stationwagon, put a good dent in the hood with his right elbow (elbow turned a nasty color as I recall - only one of several hurtin' areas on his body). He was laying on the hood with the gun across his chest staring at the sky, sort of dazed. Needless to say the twenty guys watching were hooting and giving him a lot of "support". The net deployed very nicely, although no-one really gave a damn as they were too busy laughing at Charlie.
Just thought you guys might enjoy hearing about another type of reloading and shooting from the good old days. There was another time that I shot a deer with a "smooth bore dart gun" with the dart filled with water, perfect lung shot at 51 paces, complete penetration - that is another story...
Interesting story. Would never contemplated the loads you used, but it sounds like an expansion chamber setup. Thanks for the tale, particularly about the parking lot story. Sorry about the hood of your truck.
On a lighter note, I think a sabot would work fine, but was thinking about a projectile in the 200 gr. range. Maybe 2, 2 1/2" long, not sure about that. Wonder if .17 cal would have enough stiffness to withstand the acceleration? Maybe out of Cupronickle. Very dense, tough, and heat resistant. Pretty sure this one would glow in the dark from friction. Maybe in the day too. [img]images/icons/shocked.gif[/img] Anyone know what material is used to make the sabots for the Abrams gun?
"Anyone know what material is used to make the sabots for the Abrams gun? "
Yes. Depleted Uranium for the Combat rounds. Gunnery rounds are made of aluminum.
The Army tried a Sabot rifle in the early 1970s. It got 10foot groups at 600 yards.
There's a tremendous amount of information that goes into the M1A1's ballistic computer to help it achieve 3,000meter+ hits. Things like barometric pressure, air temp, wind speed at the tank, ammo temp, ammo lot#, cant angle, even a sensor to measure barrel droop and a computer that compensates for it.....etc. There's also the power to weight ratio (powder/projectile weight). I don't know exactly what the projectile weighs, but it's a 25mm dia. dart pushed by 36 pounds of propellant [img]images/icons/shocked.gif[/img] I think it would be tough to make a tiny dart that could be pushed far enough by the cartridges we use. Maybe a .50BMG case could do it.
Having said all that, Steyr is working on a 15.2mm Sabot Launcher. It's intended as a squad-operated anti-materiel weapon. The projectile is separate from the powder charge. The powder looks like a giant plastic shotgun shell.