Speaking Of Welding

Ha! Yep. Pretty much what I was saying in my other post.

So where is Jim?

In the hospital with a broken shoulder from the recoil.

Reductio Ad Absurdum: How fast do we need to spin a 4 inch bullet traveling at Mach 3 in order to stabilize it? What do we need to slow down barrel burn out if we are pushing it at Mach 6?

Its all solvable of course, but its going to take some figuring out.

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What is that? Looks like an animal was run over repeatedly by a D9 Cat.

Oh, its the Elk Jim shot with his brand new Mach 6 Ruger American rifle shooting 50 caliber 2000 grain pointed soft point boat tails at Mach 6.4.

Bob La Londe CNC Molds N Stuff

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The older Greenhill bullet stability formula:

You could pull a muscle trying to c*ck a .50 BMG. I'd want a tree between me and the rifle. Fighter planes slowed down while firing them.

This is the biggest gun I've seen for sale in a gun store.

The first bullet may have glanced off the traffic signal support, losing its copper jacket which may have been seen falling, struck the curb near the triple overpass, and sent a concrete chip into James Tague's cheek. Oswald's aftermarket scope mount, his line of sight, was higher than usual above the bore to clear the bolt handle. The support wasn't properly examined in place because the FBI reconstruction assumed the driver was centered in the lane, while a film shows him crowding the line leftward. When finally taken down after an accident it was too weathered to tell much.

You think too small.

Airgun battleship:

So where is Jim?

In the hospital with a broken shoulder from the recoil.

Bob La Londe

----------------------------------- the big elephant rifles were claimed to kill at one end and maim at the other.

What is that? Looks like an animal was run over repeatedly by a D9 Cat.

Oh, its the Elk Jim shot with his brand new Mach 6 Ruger American rifle shooting 50 caliber 2000 grain pointed soft point boat tails at Mach 6.4.

----------------------------------- Your description applies to a hunter whose shot failed to stop the elephant. They are vengeful and leave a greasy red patch.

Oh, its the Elk Jim shot with his brand new Mach 6 Ruger American rifle shooting 50 caliber 2000 grain pointed soft point boat tails at Mach 6.4. Bob La Londe

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Latest and greatest?? Me?? More likely with the 45-70 Sharps at Mach 0.9.

There is elk and buffalo hunting here:

One of my UPS drivers told me somebody in my area, one of my "neighbors," was doing research on modern pneumatic cannons (15 years ago give or take) for military application. I don't know any of the details and he never told me who it was.

Getting into pneumatics, with natural nitrogen oxygen "air" there is a velocity limitation, but it might be faster than you might think. No its not using the vacuum and membrane method. Just straight pneumatic push against one atmosphere in the barrel.

Now guys have pushed velocities using helium with knock valve (PCP) type guns, but helium is expensive compared to air.

The way I remember the fast air guns operating with regular air was instead of releasing a burst of air behind the projectile, they locked it in place to seal an air chamber. They pressurized the air chamber, and then they released the locks holding the projectile in place. I seem to recall they were getting about 2700ish FPS. Its not all that fast compared to a lot of powder burners, but its plenty fast enough. Insane for a theoretical airgun. This was with a test rig in a lab/workshop. I don't recall if they built any practical rifles using the design.

My fastest pneumatic shoots a 14.3 grain .22 pellet around 1150 FPS per a chronograph. Not the lie printed on the box by a manufacturer. I have have a couple I could tune faster, but I have them tuned for good shot count. My current favorite shoots 25.4 grain .25 pellet at about

Nah, you just have to eat it before spring.

Nah, you just have to eat it before spring. Bob La Londe

--------------------------------- Assuming we get a spring. I'm watching for hairy elephants.

Getting into pneumatics, with natural nitrogen oxygen "air" there is a velocity limitation, but it might be faster than you might think.

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I understand Mach 1 being a "choked" flow speed limit since it's the temperature but not pressure dependent average speed of the individual air molecules. Lighter molecules like Helium move faster to have the same kinetic energy at the same temperature, heavy CO2 moves slower. Going beyond with DeLaval nozzles etc is beyond my slim knowledge of fluid dynamics (rocket science).

I understand Mach 1 being a "choked" flow speed limit since it's the temperature but not pressure dependent average speed of the individual air molecules.

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That's an oversimplification of a complex subject.

I think the primary reason Mach 1 is a choke point is that the projectile experiences excessive turbulence and reduced stability as it passes through the sound barrier. Its why long range .22LR shooters typically shoot subsonic and adjust elevation. To stay below the sound barrier. Its also why .22 magnum shooters tends to limit shots to

I have tuned air guns fast enough to break the sound barrier. The thunder crack of the pellet is the loudest part of the shot cycle. Even louder than the air blast from an un-moderated air rifle. Accuracy suffers, but its quite the pop. It just doesn't break it by enough to be useful with traditional PCPs.

Subsonic tends to be the default because its hard to get above Mach 1 long enough to be useful for the longer range shots that would benefit from it.

I don't have an answer exactly as to why traditional .22LR high velocity tends to limit to about 75 yards, other than that is the apx far zero for the maximum length of "point blank range." It varies depending on the gun, the setup, and the round, but I seem to recall its something like with a typical scope height your are 1.25-1.5 above bore/trajectory at the muzzle. Zero around 15 and zero around 75.

I'm going to pull up the ballistic calculator I use on my phone hold on a minute.

The trajectory passes zero at around 15-18 yards, rises a tiny bit more than one inch above at apogee, drops through the far zero just past 70 and an inch below around 75-80. Since for some stupid reason .22s tend to be crazy accurate (generalization) compared to other rifles this gives you a "maximum point blank range" of about 80 yards. Give or take.

By the way, this dual zero if you have your ballistics figured out allows you to rough sight in a rifle at a fairly short range. In fact it allows you to bore sight (bolt guns of course) if you have a good eye for concentricity a decent rough zero before even going to the range. Just make sure your neighbors don't freak about at you sighting a rifle through the window at their weather vane.

I don't recall the author or the name, but there is a science fiction work (short story I think) about an astronaut greeting a generation fleet of aliens coming to earth to colonize and take over. Since they have been in space for so many generations they no longer know anything about aerodynamics, and none of their craft have wings. Everybody thinks he is a traitor because he teaches them how to build air foils and how to fly. He calculates every inch of their approach from space to ground level. And the entire fleet breaks up in the atmosphere and crashes, because he had the fleet flying at exactly the speed of sound at every elevation for the entire entry. Nobody notices the single lone parachute somewhere over the breadbasket of America.

By the way, this dual zero if you have your ballistics figured out allows you to rough sight in a rifle at a fairly short range. In fact it allows you to bore sight (bolt guns of course) if you have a good eye for concentricity a decent rough zero before even going to the range. Bob La Londe

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In Army Basic we zeroed our M16s at 25 yards and they were close enough to

Maybe old news you've already heard...

Hornady did some research on their tips, found that a flat meplat works better for long range.

=== The approach decreases dispersion at long range by optimizing bullet tip shape to provide excellent overall drag and unrivaled bullet-to-bullet consistency. Specifically, the meplat must be flat—not pointed—and the diameter of the flat meplat is a specific ratio to the bullet diameter. The new technology decreases the drag variation from shot to shot, resulting in less dispersion at long range... ===

I recall something about nose shape being more efficient on air craft that were less pointed. Not being an aircraft super fan I didn't pay much attention. I guess it could be related.

You know I bought a couple boxes of Hornady high velocity stuff for 270 and 30-06 recently. I put in for some depredation hunts, and they could be anywhere. I don't know if I'll be brush busting with a "short" range fast action lever gun or taking a hillside shot across a valley. Anyway, I figured I'd get prepared. Now I want to go pull a box off my ammo shelf and take a look.

Interestingly, and maybe totally unrelated. The most accurate tightest (bragging rights tight) groups I've gotten in .223 is with the American Eagle 50gr hollow points. I wonder if that tiny little hollow point acts like a tiny little flat in practice. I was actually very surprised at how consistently they shoot given the visible inconsistency of the tips from one bullet to the next. I was stunned at how good it was, compared to my first experience with .223. I won't get into that. Just say the only way I would ever own another Mini 14 is if somebody gave it to me, and then only for as long as it took for me to sell it or trade it off.

I recall something about nose shape being more efficient on air craft that were less pointed. Not being an aircraft super fan I didn't pay much attention. I guess it could be related.

Bob La Londe

------------------------------------- This might be related:

The military M855 bullet introduced in 1982 has a small flat meplat.

I had a nice platform welded inside the frame in the tongue, but I just wasn't happy with it. It was a little lower than I would like. I planned to put the fair lead in the front rail of the trailer just above the bed. The winch would have been a little low. The cable would have had to go up to go through where I wanted to mount the fair lead. I just didn't like it. Then I ran across a couple piece of receiver tube I'd scavenged from something else. I punched some holes in the them, bolted them to the bottom of the winch, and then welded them to the platform I'd built for mounting. It puts the cable perfectly in line with where I want to put the fair lead. The cable will come through about 2 inches above the bed, just brushing the bottom roller, and almost perfectly straight when the drum is full. When half empty it won't even touch the rollers. When its down to the last layer of wrap (maximum cable out that's safe to pull) it will just touch the top roller when its straight out.

Pain in the patootie, ain't got the right chit, and it all works out. Still looking for a battery box. I don't plan to leave a battery on the trailer, but I do plan to wire it up so when I'm pulling the trailer the truck will charge the battery just like it does the break away battery on the goose neck or the fifth wheel. I reckon I'm just going to have to waste a day making a box. Can't find anything I like.

---------------------------------- A plan that's worked for me is the battery in a Noco (or other) plastic case with the strap rearranged as a centered handle. The strap tiedown brackets are bolted or Pop-riveted to the box below lid level so the battery won't tip. The short cables go to a large Anderson connector rated for the load current, so I can use the winch on either the truck or the tractor and store the battery indoors, protected from accidental shorting in the Noco.

If the Noco box is left exposed instead of in a locked metal box it needs a drain hole for rain which comes in through the lid vents. Walmart had Noco battery boxes at a good price up to Group 24, I had to spend more for Group

LiFePO4 batteries have dropped in price enough to be tempting but they may not have the current rating for winches or starting engines. Their protection circuits cut out if overloaded. jsw