Another Reason to Hate Handloader Magazine

Andy

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A few months ago they (again) busted the myth that slow powders need long barrels to get a full burn and now this month they've proven that case shape does not affect bolt thrust. Ackley Groupies will be furious.
 
Andy

The problem with your statement is many people will think you have been drinking because the information is wrong, and whoever wrote it is full of beans.

Below is the "fast" burning Titegroup powder I use in my .44 Magnum for practice and it is completly 100% burnt in the first 2.4 inches of barrel. If I used H110 or 296 powder the powder would only be 95% burnt if I had a 47 inch barrel. Slow burning powders generate pressure over a longer burn time and to take advantage of the slower burning powder you need a longer barrel. The Quickload chart below is for my 5 inch Model 29 .44 magnum and barrel length and powder burn rate will effect velocity. The problem with slow burning powders and short barrel length is too much powder is burnt "outside" the barrel and a faster powder is more efficient.

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And case shape does effect bolt thrust so another person doesn't know what he is talking about. Some British proof houses still use the old base copper crusher method. The copper crusher is located at the base of the case and the firing pin passes through the copper crusher. This method will indicate the chamber pressure delivered to the bolt face and the cases must be oiled to give a true pressure reading. If the case is not oiled the the pressure reading will be approximately 50% less than the true pressure reading.

My point being here is these base crusher readings are actual pressure readings and not mathematical guesstimates of "theoretical" pressures delivered to the bolt face.

I get Handloader magazine online and my newest is No. 285 and I don't remember my hair catching on fire and hiting the computer screen. What issues and articles did this info come from I may want to cancel my subscription.
 
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Issue 286, Oct 2013.


Article : Bolt Thrust and Related Myths

Written by John Barsness ("Mule Deer" on 24 hr campfire forums)
 
I've found that the scientific/technical level of ballistics discussions in HL mag. is rather low compared to what was being written a generation ago. There's nothing like "Pressure Factors" by Wolfe Publ. being written today, at least none that I know of.
 
Dont count on it!

I laugh when people think that the hunting/shooting magazines are like the bible!
Never to be questioned and always right!

"ALL MAGAZINES" tell readers a pile of information that is goverened and dictated by big gun/powder/hunting industry companies.

I have met a few writers from these magazines and they all told me the same thing.

They write thier article according to thier own findings, and by the time it ends up in print, the group sizes are smaller, the velocities are different, and even the firearms used in the tests, are different. It all depends on whos paying the magazine for advertising.

The one thing that cannot be denied is "PHYSICS", regaurdless of what is claimed.
 
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I have a Excel program that computes bolt thrust, I think I will become an expert gun writer.

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From the 1929 British Textbook of Small Arms.

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I wonder how many gun writers and internet experts have base copper crusher testing equipment in their basement that measures the actual force on the bolt face?

In Britain, a third set of crusher standards were developed, using a "base" crusher. The crusher was a short, thick tube placed behind a piston at the base of the cartridge, and the firing pin passed through the center. The cartridge case was well oiled before firing, to minimize cling to the chamber walls (if not oiled, the indicated pressures were about 40-50% lower). The units were generally stated in British long tons per square inch, or tsi. Pressures indicated by this method run 10 to 20% below those indicated by radial crushers. Kynamco in England still rates their production cartridges with this method.
 
I like Wolfe publishing, and John Barsness, but every once in a while both can amaze me with what hits the shelves, this was one of those times. Using the methods PO Ackley used to state lubricated cases will not cause an increase of bolt thrust is just silly, yes, his methods were seriously flawed, but that doesn't mean the results were right or wrong, just means they aren't quantifiable.

Anywho, anyone that thinks lubrication won't decrease the grip between two surfaces needs to go to reality school.
 
I like Wolfe publishing, and John Barsness, but every once in a while both can amaze me with what hits the shelves, this was one of those times. Using the methods PO Ackley used to state lubricated cases will not cause an increase of bolt thrust is just silly, yes, his methods were seriously flawed, but that doesn't mean the results were right or wrong, just means they aren't quantifiable.

Anywho, anyone that thinks lubrication won't decrease the grip between two surfaces needs to go to reality school.

Absolutely correct! The lubrication hydraulicaly prevents adhesion. No possible way for the case to stick and not move backward with minimal force.
 
A few months ago they (again) busted the myth that slow powders need long barrels to get a full burn and now this month they've proven that case shape does not affect bolt thrust. Ackley Groupies will be furious.

My personal experience with H4350 in a short barreled 308 resulted in a HUGE fireball which I could see through the scope as my view suddenly turned completely orange. I haven't read the article in question but I'd have some serious doubts about it at this point.
 
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