Case head thrust for the 480 Ruger at 48,500 PSI is 9,894 pounds again less than the 454 Casull

quote:

Originally posted by jwp475:
I just took a very accurate reading of the back thrust in my 475 with 0 PSI and the back thrust interestingly enough was also 0 pounds. It does appear that without PSI there is no back thrust.

You need a projectile to produce back thrust.

JWP stick to asking people that know what there talking about, you are just not one of the smartest guys when it comes to trying to prove a point...

While you are talking to Mr Linebaugh, have him explain back thrust to you. Then come back here and post something of value.

quote:

Originally posted by jwp475:

quote:

Originally posted by Redhawk1:

quote:

Originally posted by jwp475:

quote:

I am not trying to be a smartass here, but I don't think you guys understand back thrust enough to save your ass.

You can't help it, so it's ok.

Your one to talk, your an smartass 24/7.

Do you have any numbers on case head thrust?

No I don't, but you sure as hell did not come up with it yourself.

Also back thrust changes with the weight of the projectile, but I guess you did not know that.

quote:

Originally posted by Redhawk1:

quote:

Originally posted by jwp475:
I just took a very accurate reading of the back thrust in my 475 with 0 PSI and the back thrust interestingly enough was also 0 pounds. It does appear that without PSI there is no back thrust.

You need a projectile to produce back thrust.

JWP stick to asking people that know what there talking about, you are just not one of the smartest guys when it comes to trying to prove a point...

While you are talking to Mr Linebaugh, have him explain back thrust to you. Then come back here and post something of value.

I got those numbers from Mr. Linebaugh a bit ago as we spoke on the phone. I have been talking to John since 1985. I have also read P.O. Ackleys work on back thrust.
All you have so far is personal insults and no numbers to back up your assumption.

Of course you are correct that a projectile is neede to create pressure and back thrust. Again with Pressure one can nopt have back thrust.

quote:

Originally posted by Redhawk1:

quote:

Originally posted by jwp475:

quote:

Originally posted by Redhawk1:

quote:

Originally posted by jwp475:

quote:

I am not trying to be a smartass here, but I don't think you guys understand back thrust enough to save your ass.

You can't help it, so it's ok.

Your one to talk, your an smartass 24/7.

Do you have any numbers on case head thrust?

No I don't, but you sure as hell did not come up with it yourself.

Also back thrust changes with the weight of the projectile, but I guess you did not know that.

JWP, pressure is always going to be there, that is the nature of the beast. But there is more to back thrust than just pressure.

Yea I don't have all the numbers you posted. But at least I have enough common sense to know you cannot post numbers and that is it, you have variables that will change the pressure and back thrust. You just gave one example of one variable.

quote:

Also back thrust changes with the weight of the projectile, but I guess you did not know that.

Not exactly if one shoots a 420 grain projectile at 30,000 PSI and then shoots a 350 Grain projectile at 50,000 PSI then the lighter, higher pressure projectils has the most back thrust.
The case head (or back thrust) thrust is directly related to pressure not projectiles wieght

JWP,
You learn just enough to be dangerous.

You consider correct infomation to be dangerous?

JWP has all the answers and knows everything. I think JWP needs to have his own web site.

JWPknowsitall.com

All you have to do is ask him....

No I don't consider correct information to be dangerous, but when you post pressures and back thrust numbers, and don't explain how they are obtained or how they can chance, yea I consider that dangerous.

Redhawk1, I think your hatred for jwp475 is clouding your ability to comprehend what it is that he is saying.

Pressure is not related to back thrust? Are you kidding me? What do you think the bullet weight creates but pressure.

Back thrust is absolutely determined by pressure. Projectile weight and surface area, combined with the powder charge and the bolt-face surface area (rim diameter), as well as the cartridge case configuration (bottle-neck cases transfer thrust in a more dynamic way), all play into how the PRESSURE is transfered rearward. Bullet weight in and of itself is not the deciding factor. Actually a .30-06 has more backthrust than any of these handgun cartridges and as you know a 200 grain bullet is considered heavy in .30 caliber.

And as an aside, I too spoke with John Linebaugh, and he said that they have run pressures up over 90,000 psi in the .475 in Super Blackhawks and have never stretched a frame, and the SRH is an even stronger frame.

quote:

Originally posted by Redhawk1:
JWP has all the answers and knows everything. I think JWP needs to have his own web site.

JWPknowsitall.com

All you have to do is ask him....

No I don't consider correct information to be dangerous, but when you post pressures and back thrust numbers, and don't explain how they are obtained or how they can chance, yea I consider that dangerous.

redhawk1knowsnothing.com a place for old wives tales and conjector

quote:

No I don't consider correct information to be dangerous, but when you post pressures and back thrust numbers, and don't explain how they are obtained or how they can chance, yea I consider that dangerous.

Perhaps you missed my earlier post..

quote:

I got those numbers from Mr. Linebaugh a bit ago as we spoke on the phone. I have been talking to John since 1985.

Now Whitworth, think about what you said. If you think Redhawk's opinion is clouded, what about yours for what JWP says We know he's your friend, but sometimes even friends can be wrong. And when that friend has a disposition like a water moccasin, the rest of us can easily see it. Why can't you?

Redhawk, I told you, you shoulda left him on ignore. If Jack Huntington and John Linebaugh didn't say it, jwp has no original thoughts of his own. Put him on ignore and enjoy the forums like I do now.

quote:

Originally posted by george roof:
Now Whitworth, think about what you said. If you think Redhawk's opinion is clouded, what about yours for what JWP says We know he's your friend, but sometimes even friends can be wrong. And when that friend has a disposition like a water moccasin, the rest of us can easily see it. Why can't you?

That would be just like you and Redhawk. Redhawk is just wrong in this case and he cannot seem to concede irrespective of your opinions of jwp. Also, jwp isn't the one who made this personal.

I truly didn't SEE this one so I can't say,but jwp is no virgin and he damned sure neither understands or accepts the laws of physics. He's ALWAYS had to be right and if it's not Linebaugh or Huntington, YOU KNOW he doesn't think they're worth spit. When a person can't understand basic science, I don't care WHO it is, they will never be an "expert" except in their own imagination.

And how dare you fault me for siding with Redhawk when my "guilt" in no greater than yours? That's patently unfair. Redhawk didn't write the laws of physics. If HE was wrong, I'd tell HIM. Can you say the same thing?

quote:

Originally posted by george roof:
And how dare you fault me for siding with Redhawk when my "guilt" in no greater than yours? That's patently unfair. Redhawk didn't write the laws of physics. If HE was wrong, I'd tell HIM. Can you say the same thing?

How dare I?? I'm starting to smell some self-riteousness...... Yup, I would tell him if he was wrong, but he's not wrong in the least in this case.

quote:

Originally posted by george roof:
Now Whitworth, think about what you said. If you think Redhawk's opinion is clouded, what about yours for what JWP says We know he's your friend, but sometimes even friends can be wrong. And when that friend has a disposition like a water moccasin, the rest of us can easily see it. Why can't you?

Redhawk, I told you, you shoulda left him on ignore. If Jack Huntington and John Linebaugh didn't say it, jwp has no original thoughts of his own. Put him on ignore and enjoy the forums like I do now.

If I have an experts opion are any reference material that suports my position then you say that I hve no original thoughts. If you have no facts on your side and are unable to baffle with bull shit you then turn to the personal insults is standard operating procedure for you two.

quote:

Originally posted by jwp475:

quote:

Originally posted by george roof:
Now Whitworth, think about what you said. If you think Redhawk's opinion is clouded, what about yours for what JWP says We know he's your friend, but sometimes even friends can be wrong. And when that friend has a disposition like a water moccasin, the rest of us can easily see it. Why can't you?

Redhawk, I told you, you shoulda left him on ignore. If Jack Huntington and John Linebaugh didn't say it, jwp has no original thoughts of his own. Put him on ignore and enjoy the forums like I do now.

If I have an experts opion are any reference material that suports my position then you say that I hve no original thoughts. If you have no facts on your side and are unable to baffle with bull shit you then turn to the personal insults is standard operating procedure for you two.

Just in case anyone has jwp on ignore......

Whitworth, I was not wrong, if you go back and read all the posts you will see, you said "454 Casull which produces a whole hell-of-a-lot more pressure than a .480 or .475. There have been no problems with the .454s"

I replied there was a difference between pressure and back thrust and there is, but to determine the back thrust, you need pressure to push the bullet out of the case, the forward momentum of the bullet creates back thrust, and the heavier the bullet the more back thrust you get.

If you took a gun and loaded it with different bullets of different weights and could measure the pressure in each case and keep the pressure the same, the case with the heavier bullet with equal pressure with have more back thrust. It is as simple as that.

Now to JWP, first thing he says here is, "Since the SRH & RH revolvers are so inherently weak I am willing to pay 100 dollars each. I will sacrifice 100 for each revolver in order to eliminate the grave safety risk these revolvers present to the general public."

No where did anyone say the "SRH & RH revolvers are so inherently weak " Now did they?

I replied why does he have to be a smartass all the time.

I posted, "I am not trying to be a smartass here"
JWP reply's. "You can't help it, so it's ok."

And the battle of words is on, but you say I started it, I think your friendship with JWP clouded your judgement.

JWP throws out some numbers and try's to baffle everyone with a little knowledge, and everyone is suppose to agree and just think he is right.

It goes back to simple science and the laws of motion.
You guys focus on one thing, you don't take into account, it take a combination of thing to make back thrust and when you change one of them variables, you change the amount of back thrust.

And I don't have a hatred of JWP, but I can't stand someone that thinks that what little knowledge on a subject they possess is the only truth and what anyone else posts is wrong. .

You are wrong in saying back thrust is absolutely determined by pressure. But I never said bullet weight alone determines the amount of back thrust. I said increasing bullet weight will increase back thrust.

I can smoke a 200 gr. bullet out of my S&W 460 Mag and the recoil is not back at all, now when I smoke a 300 gr. bullet out of my S&W 460 Mag, the recoil increases, that is because there is more back thrust. I bet the pressures are very close in both cases.

quote:

Originally posted by jwp475:

quote:

Originally posted by george roof:
Now Whitworth, think about what you said. If you think Redhawk's opinion is clouded, what about yours for what JWP says We know he's your friend, but sometimes even friends can be wrong. And when that friend has a disposition like a water moccasin, the rest of us can easily see it. Why can't you?

Redhawk, I told you, you shoulda left him on ignore. If Jack Huntington and John Linebaugh didn't say it, jwp has no original thoughts of his own. Put him on ignore and enjoy the forums like I do now.

If I have an experts opion are any reference material that suports my position then you say that I hve no original thoughts. If you have no facts on your side and are unable to baffle with bull shit you then turn to the personal insults is standard operating procedure for you two.

JWP you are a big boy, so am I. You have thrown your jabs at me, and I have at you. If you can't take it, tough. Don't whine like some baby if I insult you, sometimes that seams the only way to get your attention.

But it goes both ways, your friends on here always seem to come to your rescue and pat you on the head and tell you it will be alright.

That is what I like George, he will tell me if I am full of shit, he does not patronize me to keep me as a friend. Him and I are the same, if we think you are full of shit we will tell you.
Don't take it to heart, that's just how we roll.

I can assure you that jwp possesses a whole lot more than a little knowledge about this stuff. If you couldn't read the humor in his comment about buying up all of the SRHs, then you really need to lighten up. You suggested that he call John Linebaugh to confirm what you were saying, and he did just that in order to provide you with references that were credible.

I still cannot figure out why you cannot see that it is pressure that pushes the case back. How is it then that the .30-06 produces significantly more back thrust than a .475 even though it is shooting a bullet that is less than half the weight of the .475?

quote:

It goes back to simple science and the laws of motion.
You guys focus on one thing, you don't take into account, it take a combination of thing to make back thrust and when you change one of them variables, you change the amount of back thrust.

And I don't have a hatred of JWP, but I can't stand someone that thinks that what little knowledge on a subject they possess is the only truth and what anyone else posts is wrong. .

You are wrong in saying back thrust is absolutely determined by pressure. But I never said bullet weight alone determines the amount of back thrust. I said increasing bullet weight will increase back thrust.

I can smoke a 200 gr. bullet out of my S&W 460 Mag and the recoil is not back at all, now when I smoke a 300 gr. bullet out of my S&W 460 Mag, the recoil increases, that is because there is more back thrust. I bet the pressures are very close in both cases.

Back thrust is pressure related, recoil is momentum related. If the surface area of the cartridge is the same in 2 loadings the loading with the highest pressure will have the most back thrust no matter the bullet wieght. A 420 grain bullet at 30,00 PSI wil have less back thrust than a 350 grain bullet at 50,000 PSI despite the lower bullet wieght, simple physics. The same as a hydrulic piston if they are the same size then the one with the most pressure will lift the most wieght.

quote:

Originally posted by Redhawk1:
That is what I like George, he will tell me if I am full of shit, he does not patronize me to keep me as a friend. Him and I are the same, if we think you are full of shit we will tell you.
Don't take it to heart, that's just how we roll.

If this statement were true, he would have stepped in and corrected you on your theory of back thrust. Why didn't he? See, I think he will side with you no matter what -- just like you are accusing me for blindly siding with jwp.

I am through with this mud-slinging fest. Y'all can stay and argue if you like, but I am outa' here...........

If you took the 100 dollar offer as anything but humorus than you missed the boat.

You can not change the laws of physics pressure and surface area are the factors that determine back thrust..

I'm out of here on this one.. Carry on

Whitworth, he gave me numbers without all the information that is associated with obtaining back thrust. Those numbers will change once one variable is changed.

Also the case itself can change the way pressure is used. you cannot compare different cases and come up with the same results. Bottle neck cartridges work differently than straight wall cases. You are trying to compare apple to oranges.

George does not have to step in and tell me I am wrong, because I am not wrong.



JWP, don't compare hydraulics with firearm pressures. I am a hydraulic specialist. I have 10 years of working on aircraft, and 20 years in industrial maintenance working with hydraulics. So I know a lot about hydraulics.

Increasing hydraulic pressure only speed up the movement of an object. I have used low pressure cylinders that will lift more than a high pressure cylinder. I have lifted crashed aircraft with only 20 psi of pressure.
But there is a lot of different kinds of cylinders, and they can only take so much pressure before you blow one. Look at floor jacks, they operate under low pressure, and can lift cars very easy, by adding more pressure, all you do is speed how fast you lift the car, not how much more it can lift.
There is a big difference between Hydraulics and case pressures in firearms.

There is just to much on Hydraulics to post here and get my point accross.

Whitworth, thanks for sharing. LMAO. Ther was nothing "self rightous" in my comments unless you're feeling guilty. There's neither any humor in ignorance and stupidity either. We've gone from the laws of motion, to the laws of physics and now we're in the laws of hydraulics and jwp has shown the world his entire level of competence. I suppose you can find no flaws in his logic so you defend his insufferabiltiy, but I simply called a "spade" a "spade". Thankfully I don't have to worry about what he pulls the trigger on, but I sure as hell he doesn't work at AAMCO.I'm going someplace else to get my brakes fixed.

Dan Lilja doesn't know anything about case head thrust either, he had the nerve to post this on his web site,

quote:

Bolt Thrust
Bolt thrust is easy to calculate. Only two inputs are required. They are peak chamber pressure in PSI and as mentioned, the inside area of the case head that the gas pressure can work on. The formula then is:

THRUST=AREA*CPSI Where:

AREA=3.1416*(HS/2)^2

HS=the diameter of the inside of the case head.

Mr. Lilja thinks that only the area and the Chamber pressure are required to calculate case head thrust, but we have learned better from george roof and Redhawk1. Redhawk1 has educated us to the fact that bullet wieght matters.

My, my ~ so many terms, thots all differing. I know nothing but have always thot that 'chamber' pressure is the same on all surfaces of the containment. Now I don't know whats what anymore. I recall back in the 50's there was the popular belief that case lube contributed to catastrophic failure due to increased 'back-thrust'. Today, I wonder if it is more likely due to pressure reacting w/the lube/oxidizer like oil in a lox line or tank fittings in presence of high pressure?

Pls don't let me distract anyone ~ nobody's side

You're still not dragging me back in.......

JWP you are giving information on Bolt Lug Strength.
Read the whole article, it takes more than just those two numbers to get Bolt Lug Strength.

Here is the whole article you are quoting. only part of.

A Look at Bolt Lug Strength
By Dan Lilja

All action designers are concerned primarily with producing a safe and functional product. All other considerations such as weight, finish, eye appeal and other cosmetics are secondary. From a safety standpoint, the strength of the bolt lugs is of prime concern. Bolt lug shear strength depends on several inputs. Some are fairly obvious, but others may not be at first glance. The number of lugs on the bolt is in the obvious category, as are the axial length of the lugs and the width of the lug. Or more precisely, not the actual width but the length of the radial segment of the lug that's connected with the bolt body. Also, the strength of the material is important.

The shear strength is calculated from these factors, as I will explain in detail a little later. This shear strength must be greater than the amount of backwards thrust on the bolt generated by the cartridge being fired. So another number that must be calculated is bolt thrust. Bolt thrust is fairly simple to calculate and depends on the inside diameter of the cartridge case being fired and the chamber pressure.

Also of interest, but not necessarily crucial to safety, is the amount of flex or spring in the lugs while they're under the thrust load.

So then, we will look at three different calculations related to bolt lug strength: lug shear strength, bolt thrust as generated by the cartridge case, and lug flex.

Shear Strength
Unless a cartridge case undergoes a complete head separation upon firing, the side walls of the brass case will stick against the chamber walls. Under some circumstances they may absorb as much as half the thrust. Case walls or a chamber that are oily will reduce this friction. So the action designer will not take this aspect into consideration when designing the lugs to more closely simulate a complete case head failure.

Also, in the formula that will follow the calculated strength value will be reduced by half, adding an additional safety margin of two. This is in keeping with generally accepted engineering practice for suddenly applied loads.

The formula for calculating lug shear strength is:

LS=(L*LL*NL*YS)/2

Where:

LS is the calculated lug shear strength
L is the length of the arc segment
LL is the axial length of the lugs
NL is the number of lugs on the bolt
YS is the yield strength of the material the lugs are made from

As mentioned, this number is then divided in half for a safety margin of two.




The only thorn in this formula is the length of the arc segment. We need to determine the total area in shear. Because the root of the lugs are joined to the bolt body on a radius, the length of the radial segment needs to be calculated. The formula for this calculation looks like:
L=.01745*R*ANG

where:

R=the radius of the bolt body
ANG=arccosine of the angle of the segment or
ANG=arccosine(x/SQR(1-x^2))+1.5708

where:

x=1-(R-.5*SQR(4*R^2-W^2))

where:

R=the radius of the bolt body
W=the width of a bolt lug

If this all seems a little imposing, we'll list a short computer program in GWBASIC later that will hopefully make more sense.

The type and hardness of the steel the bolt is made from is important too. This part of the equation falls under the yield strength input. The yield strength is the maximum amount of pressure the steel can take without becoming permanently deformed. Up to this point it will return to its original condition. Since 4140 type chrome-moly is probably the most common type of steel used in bolts, I'm including a list of the yield strength for this steel at various Rockwell `C' hardness values.

ROCKWELL 'C' HARDNESS 4140 YIELD STRENGTH PSI
20 83,500
22 87,000
30 135,000
34 148,750
37 159,000
42 178,000
46 195,000
49 211,000

Bolt Thrust
Bolt thrust is easy to calculate. Only two inputs are required. They are peak chamber pressure in PSI and as mentioned, the inside area of the case head that the gas pressure can work on. The formula then is:

THRUST=AREA*CPSI Where:

AREA=3.1416*(HS/2)^2

HS=the diameter of the inside of the case head.

I sectioned some cases and measured the inside diameters and found that they were as follows:

CARTRIDGE CASE INSIDE DIAMETER (HS)
222 .300"
PPC .370"
308 .385"
MAGNUM .420"
378 WBY MAG .500"
50 BMG .680"

The thrust is measured in pounds per square inch.

Bolt Flex
Bolt flex or spring is an interesting measure that is easily calculated using the numbers we have already determined for area in shear and bolt thrust. Another number that we will introduce into the equation is the shear modulus of elasticity. For steel this number is 11,500,000 pounds and is a constant. It does not change regardless of the type of steel being used or the heat treatment of the steel.

The equation looks like:

FLEX=THRUST/(SA*11500000)

where:

SA=the shear area of the bolt lugs or:

SA=L*LL*NL

Or more simply put, the area in shear for all lugs is multiplied times the shear modulus, and this number is divided into the thrust. Often the resulting number will be in the .001"-.002" range. This explains why it becomes necessary to bump the shoulders of brass cases back after a few reloadings. New brass is elastic enough that it will return to its original shape, but with progressive loadings the brass becomes more plastic until it does not return to its original form at all. Cases become sticky, bolt lift more difficult and eventually the cases have to be replaced. With very high pressure loads this can happen on the first firing.

Also, the lug abutments in the receiver are set back a small amount too, compounding the problem. In fact it is possible for machining operations on the action (such as scope base screw or guard screw holes, magazine cutouts, and feed ramps) to weaken it to the point that the lugs have more strength than the action. In single shot bolt actions like we will be reviewing, this would not be the case, but with light weight repeaters this is entirely possible and quite probable, at least with the bottom side abutment.

So from a bolt flex standpoint we can see that the more lug area in shear, the less case stretch we will have. And this explains why higher pressure loads cause case stretching and sticky bolt lift. The obvious ways to increase shear area are: increasing the number of lugs, lengthening the lugs, or making them wider. Increasing the minor diameter of the lugs would help too, but to a lesser extent.

Okay Redhawk,

This has been entertaining up to a point, but you simply appear not to be smart enough to figure out what you are being told. What is needed to calculate head thrust, whether it acts on a standing breech or the bolt face of a rifle is the chamber pressure and the area inside the case head. Lilja and Linebaugh have both said as much, yet you continue to use your "common sense" to tell everyone these two guys, and anyone else disagreeing with you is wrong.

From the content of his posts, george appears to be the kind of guy that knows bullshit when he sees it in the mirror. Please do not try to dazzle me anymore george.

The both of you have wasted two pages of bandwidth arguing and calling names on people who do not agree with you; bad thing is I do not see an end in sight, even when other posters have cited their references. I still have not seen either of you post a credible reference.