.30 Carbine - Magnetic

A modest proposal:  Modify the .30 Carbine to facilitate its use in firearms operated by simple, blow-back principles.

It is commonly believed that only low-powered cartridges can be fired in simple (read, inexpensive to manufacture) firearms with blow-back operation.

That is not true.

1927 technology
The Oerlikon 20mm cannon used blow-back operation.  Specs:

• 2700 fps (830 m/s)
• 2,000 grains (130 grams)
• 650 rounds per minute when fired in automatic mode
• That is about 12 times more powerful than the 30-06 GI Joe was shooting out of his Garand in WWII

And the aircraft mounted version weighed about 65 pounds.

How did they make it work?

A typical cartridge looks like this when inserted into the chamber

Looking at the base (or head) of the cartridge we see that about 5mm of the cartridge is unsupported by the barrel.  That is necessary so the extractor can engage the groove machined around the base of the cartridge.

That would be catastrophic except that there is a tremendous amount of "beef" (well, brass) left in the casing for that very reason.

This is a calculated pressure trace for an M-1 .30 caliber Carbine with an 18 inch barrel.  Exit pressure is 1750 psi at bullet's exit from barrel.  Pressure is 3500 psi at 10"...a pressure that unsupported brass might be able to withstand.

In blow-back operation the mechanism is never locked.  It uses the inertia of the bolt to react the forces pushing the bullet down the barrel.  That fact that the bolt is not locked into the receiver or barrel means that it is traveling rearward even as the bullet is still in the barrel and the gas pressure is still high.

If the bolt assembly of an M1 Carbine weighed the same as the slide on a Glock 19 (about 12 ounces) then it would travel back 0.36 inches or 9mm before the bullet exited the barrel. That means an additional 9mm of case would be unsupported and be required to contain the gas pressure.  This is a simple ratio thing.  24 ounces would result in 0.18" of travel, a 48 ounce bolt would result in 0.090" of travel and so on.

So how did the Oerlikon manage to handle the power and the pressure of the 20X101mm Anti-Aircraft round in a firearm with a functional weight?

They cheated.

"That means an additional 9mm of case would be unsupported..."  But what if the cartridge did not start out with five millimeters of case already sticking out of the chamber.  What if the cartridge had to slide rearward 4mm before it was even flush with the end of the barrel.  Then, 5mm (9mm motion .MINUS. 4mm sub-flush) of the cartridge would be protruding from the chamber as the bullet exited the barrel and the gas pressure blew off.  Five millimeters, just like a non-blowback, locked bolt design.

It was necessary to design the cartridge with a "rebated rim" so there was room for the extractor to engage the cartridge when it was down-in-the-hole.  And the cartridge walls are nearly straight which facilitates pulling the cartridge out without torturing the brass.

SAAMI spec drawing for the .30 Carbine

Looks almost doable with a .30 Carbine until you subtract 0.160" from the diameter of everything on the base of the cartridge to provide clearance for the extractor.  Unfortunately that takes the diameter for the extractor groove down to 0.150" which is smaller than the diameter of the primer pocket.  No good!

But what if...
But what if we did not use a mechanical extractor?

The fired round automatically extracts itself when fired.  That is what blow-back means.  The cartridge pushes the bolt back, not the bolt pulls the cartridge out of the cylinder.

One needs an extractor to clear the firearm of unfired rounds (very low force requirements) and clearing the spent brass in the case of a "squib" round.

Something we have now, that they did not have in 1941 are NdFeB magnets.  Rather than screw around with mechanical extractors, why not specify the use of steel cased ammo and insert a couple of small diameter NdFeB magnets into the head of the bolt?  Incidentally, steel cased .30 Carbine ammo is both inexpensive and readily available.

In fact, one can increase the case capacity of the .30 Carbine case by about 10%  if you fully embrace the concept of magnetic extraction.  It entails completely eliminating the extractor groove and moving the interior geometry of the case (less the primer pocket) aft by 0.12" (3.0mm).

Viola!

The .30 Carbine - Magnetic
The same exterior dimensions of the .30 Carbine case EXCEPT

There is no extractor groove and the rim "edge" geometry is optimized for impact extrusion forming technology to eliminate any machining operations on that end of the case.

The case must be made of magnetic material (i.e. steel).

The only other update would be to increase the max COAL by 0.90" (2.3mm) so more aerodynamic  "varmint" bullets like the Speer 125 grain TNT can be used without unduly compromising the powder space.  The advantages of the more streamlined bullet are pretty big.  At two hundred yards, the 110 grain round nose retains 441 foot-pounds of energy compared to the 125 grain spitzer's 675 foot-pounds of energy.  That is a BIG deal.

Canada: Quietly one-upping the USA...once again

Canadians have been watching the civil strife in places like Berkeley, California (USA), Ferguson, Missouri (USA) and Baltimore, Maryland (USA) for the last few years.

They watch with disbelief or amusement or concern depending on their political beliefs.

All of them think it is in poor form.  Selected quotes from around the country:

Look at the high sticking!!

Use the boards.  Use the boards!

That chick could really hip-check if she had any form.  Why won't she hip-check?

Icing!  D&%*-it.  Where is the whistle?

Fight! Fight! Fight! Fight!

Canadians are not ones to idly sit by when there is work to be done.  Canadians are a tough and pragmatic people.  They shave with chainsaws!  Except the men, who depilate using thermobaric methods fueled by starting fluid and high proof spirits.

As the twig is bent...
As the twig is bent, so grows the tree.

Canadians are still close enough to reality to realize that young people (twigs) will be young people.  Blessed with abundant energy and an excess of testosterone, they push and sometimes they push hard.  Life is better for everybody when we stop trying to treat them as fully-formed adults and give them a venue where they can refine themselves via mutually knocking the edges and corners off of each other.

Few things are better for the formation of young character than the athletic field, pitch or rink. An outlet for energy and a laboratory for the effects of games where there are few rules.

Hamilton, Ontario brings back street hockey. 

Well played, Canada.  Well played.

Sadly, few in the US will see footage of 10 year old Canadians playing street hockey.  Pity.  Maybe if they played by the lights of burning tyres.

Jarrett

I wondered how Jarrett was going to handle being cast into the wilderness without benefit of Secret Service protection.

It sucks when you whip the sharks into a feeding frenzy and you find yourself outside the shark cage.

I have to wonder if she has some inside information about some chaos that is about to happen.

If forced to choose between noble intent and craven sense of self-preservation...I know which I would attribute her actions to.

More pruning pictures

Another four hours in Salamander's orchard today.  I found a tree that was photogenic to use as a model.

Before photo.  You can see much wood being carried high in the tree.  The step ladder is 8' tall.

After photo.  I probably should have pruned the one on the right side that sticks up so high but the weight of the fruit should pull it down.

After photo from a different angle.

Poison Ivy, an occupational hazard.  Mrs ERJ makes me shower before I come within 6 feet of her after I have been chainsawing on trees with Poison Ivy.

Quirky thoughts

I pass this sign on the way to Salamander's orchard.

Something just happens in my head and this is what I see.  Freudian?

Meanwhile, back in Salamander's Orchard

Yesterday was low 30s (Fahrenheit) and the wind was about ten miles per hour out of the WNW.

A grafted persimmon tree to be moved.  The graft is about mid-way, and is covered with blackend parafilm.

I got a ton of roots on this one.  We had four inches of rain a few days ago and the tap root pulled up nicely.  I rarely do this well.  You can see feeder roots (laterals) slightly below the words "COMPLETE NUTRITION"

Water in the bottom of the hole.

Two grafted persimmons planted, wrapped with newspaper to armor against rabbits and staked to prevent windwhip and marked with surveyor flags to reduce the risk of death-by-mower.

On to pruning

This is a picture of a real tree with red lines where I intended to prune.  It is difficult to see much so I threw together some simple graphics.

Human is scaled to about six feet tall.

This is the "after" picture.  The tree is still taller than I would like because there were few live branches in the lower part of the canopy.  The ladder is 12' tall.

Pruning old trees puts a lot of wood on the ground.

My estimate of twenty more hours in the orchard was too low.  There are 45 trees in this portion of the orchard and I pruned 9 trees in three hours.  The dragging of the brush will take as long as the trimming of the trees.  That is thirty hours in just the pruning of the trees.  That does not include replanting "holes", mowing, fertilizing and spraying herbicide.

Bonus pictures

Something sparkly caught my eye as I was driving to Salamander's Orchard. 

Ice Bells.

Ice bells occur after a heavy rain followed by very cold nights cause water to freeze on twigs and brush.

Zoomed in a bit closer.

Universal Basic Income

Let's pretend to be scientists.

We have a hypothesis:  That Universal Basic Income would improve people's lives and most especially the lives of people living on the lower end of the socio-economic spectrum.

We choose some metrics like income levels of the bottom quintile and rates of substance abuse to use as proxies for more general outcomes.

Then we want to run an experiment.

We look for a sample to use as white mice.  Because our hypothesis is that Universal Basic Income most helps to those on the lower end of the spectrum, we look for a sample that is near the bottom.  Our thinking is that the advantages of UBI will not be diluted by other, extraneous factors.  Any gains should be easiest to see and measure.

Casting about, we find a distinct population with:

• A per capita income that is 40% of the national average
• A poverty rate that is 400% of the national average
• Alcoholism related death rates that are 500% of the national average

Then we give them Universal Basic Income and measure the outcomes ten years later.

Guess what, that experiment has already been run.

Results:

...(T)he (samples') mean poverty rate rose from 25% to 29%. Some (samples) did worse: among the Siletz poverty jumped from 21.1% to 37.8%.

“These (casino) payments can be destructive because the more generous they become, the more people fall into the trap of not working,” says Ron Whitener, a law professor, tribal judge and a member of the Squaxin Island Tribe in Washington state. Of the 17 tribes in the study that handed casino profits directly to members, ten saw their poverty rates rise. Of the seven tribes that did not, only two saw such an increase

With free housing and health care, “a lot of people have figured out a way to use the system to survive,” he says. “Why get a job if you don’t need one?”

And from another source

Landry noted that when Southwestern tribes began making high oil-lease payouts, rates of alcoholism and deaths from accidents rose.

"We have a lot of young families," Landry said. "We've got kids having kids. We have teen-age parents. It's hard enough when you're that young with all the issues you're dealing with. You don't know how to save. You're not prepared to deal with it. We've seen it before in Indian country and it's never a healthy situation."

Conclusions:

• Many recipients of Universal Basic Income will increase their consumption of alcohol and other drugs.  "Hey, I have the money and don't have to go to work in the morning."
• Many recipients of Universal Basic Income will either experience or be guilty of domestic violence fueled by alcohol, drugs and rage
• Many recipients of Universal Basic Income will not physically move as much and this will impact obesity, diabetes and heart disease rates
• Many recipients of Universal Basic Income will experience an economic failure-to-thrive
• Many recipients of Universal Basic Income will become locked into subsistence levels of living because they will disconnect from work, the engine that can pull them up
• Many recipients will pull income forward by buying products and services on "time".  Often, those purchases are ill-considered.  What good is a Winnebago when the payments do not leave you with enough money for gas?  Net results...UBI is soaked up and recipient is in the same, dire straits as before.
• The children of people receiving Universal Basic Income will normalize that existence and the idea of "working" will be completely alien to them

It comes down to two fundamental questions:

Which do you trust: Empirical data .OR. self-reporting and anecdotal data.

Which is more important:  Feeling good about ourselves .OR. helping people in ways that measurably improve their outcomes.

Fake News Friday: Crow Morality

As long as we are discussing road kill....

The University of Massachusetts documented a stunning rise in crow mortality.

After screening for West Nile virus and other pathogens, it was determined that the dead crows were all road-kill.

This was extremely puzzling because crows are highly intelligent birds.  Even though much of their diet is other road-killed carrion, crows are able to avoid being mowed down by virtue of posting "sentry" birds to alert the feeders to oncoming traffic.

Further study indicated that the vast majority of the dead crows, something like +95% of them had been struck by trucks.  This is far more than the percentage of trucks in the rolling fleet.  Something about trucks made them incredibly more lethal to crows than ordinary passenger vehicles.


After much study the breakthrough was found by a city boy from Boston.

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He noticed that every sentry crow was was capable of saying "Caa."  "Caa."

But none of them were capable of enunciating "Truck."  "Truck."