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  #91  
Old 03-05-2021, 09:16 PM
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Originally Posted by Salavee View Post
All I'm suggesting is using Net pressure Vs Gross (peak) Pressure... very similar to using Gross horsepower vs Net horsepower in an auto engine.Its the Horsepower that gets to the pavement that does the real work. In a firearm, I simply maintain that is the net muzzle pressure that does the real work.. (resulting velocity).. not the gross pressure. The gross pressure is just a figure that can be measured, primarily for safety reasons, as opposed to the measurable true net pressure... or average pressure, for that matter. If the gross pressure is too high, no doubt, there will be an engine or drivetrain failure somewhere along the way.The same principle goes for a firearm.

Now, for the sake of teaching me a lesson for being so stupid for even daring to mention it, will you, or Elk ,school me precisely, on what the problem is with using net muzzle pressures to consistently, and accurately, determine the resulting muzzle velocities.. I'm listening.
If by net muzzle pressure you mean average barrel pressure I donít know why you call it muzzle pressure. But I know from pistol carbine rounds if you load powders of different burn rates to the same velocity the slower powder will require a bigger charge and has more report because of the higher muzzle pressure even for the same speed. Of course the bigger charge has produced more gas for the same barrel volume itís a bigger bang at the muzzle without producing higher velocity. For some reason the faster charge has accelerated the bullet more efficiently and the higher muzzle pressure of the bigger slower charge means wasted energy not more velocity in this instance
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  #92  
Old 03-05-2021, 09:21 PM
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There are so many people on here, that are smarter than Sir Issac Newton, I and a few others on here, don't believe that, so we'll keep following his laws, Until your names precede his in the Halls of Science. F x M = A .
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  #93  
Old 03-05-2021, 09:25 PM
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Originally Posted by marxman View Post
If by net muzzle pressure you mean average barrel pressure I donít know why you call it muzzle pressure. But I know from pistol carbine rounds if you load powders of different burn rates to the same velocity the slower powder will require a bigger charge and has more report because of the higher muzzle pressure even for the same speed. Of course the bigger charge has produced more gas for the same barrel volume itís a bigger bang at the muzzle without producing higher velocity. For some reason the faster charge has accelerated the bullet more efficiently and the higher muzzle pressure of the bigger slower charge means wasted energy not more velocity in this instance
At the muzzle, both Muzzle pressure and Average barrel pressure are Equal.
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  #94  
Old 03-05-2021, 09:36 PM
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At the muzzle, both Muzzle pressure and Average barrel pressure are Equal.
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Old 03-05-2021, 09:45 PM
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  #96  
Old 03-05-2021, 09:56 PM
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There are so many people on here, that are smarter than Sir Issac Newton, I and a few others on here, don't believe that, so we'll keep following his laws, Until your names precede his in the Halls of Science. F x M = A .
Even I can't get it right
F=MA
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  #97  
Old 03-05-2021, 10:13 PM
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Originally Posted by Sashi View Post
At the muzzle, both Muzzle pressure and Average barrel pressure are Equal.
Not if the bullet has gone only halfway down the barrel. Your riddles are just too clever
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  #98  
Old 03-06-2021, 01:16 AM
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Originally Posted by marxman View Post
If by net muzzle pressure you mean average barrel pressure I donít know why you call it muzzle pressure. But I know from pistol carbine rounds if you load powders of different burn rates to the same velocity the slower powder will require a bigger charge and has more report because of the higher muzzle pressure even for the same speed. Of course the bigger charge has produced more gas for the same barrel volume itís a bigger bang at the muzzle without producing higher velocity. For some reason the faster charge has accelerated the bullet more efficiently and the higher muzzle pressure of the bigger slower charge means wasted energy not more velocity in this instance

As to your pistol carbine powder, the slower powder usually does require a larger charge will require more dwell time in a barrel than will the faster powder. Extend the barrel length a bit and the difference in velocity will become obvious.

Average barrel pressure is not muzzle or exit (net) pressure . I guess that's why its sometimes called exit pressure. I maintain that one can use projected exit pressure to measure muzzle velocity by simply using the net, or exit pressure projections taken at the muzzle just prior to bullet exit. It is equal to, and more consistent than you can get using peak pressure as a MV indicator. Peak pressure is listed in manuals as a guideline regarding safe pressures. That was mentioned, and equal muzzle pressure provides equal muzzle velocity.. that's all I said, but we have been using peak pressures for ever, haven't we ? I wasn't suggesting anyone use exit pressure, it's just a better indicator of MV.. in my opinion. The problem arose on this topic because I didn't mention what area the pressure was measured at when I first posted about equal pressure and equal velocity. Maybe you guys can ease up a bit now.







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  #99  
Old 03-06-2021, 07:27 AM
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equal muzzle pressure provides equal muzzle velocity.. that's all I said,
Look at the graph, one curve has more than double the pressure at the muzzle, yet the velocity is equal, so pressure at the muzzle does not determine velocity.

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  #100  
Old 03-06-2021, 08:58 AM
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Originally Posted by elkhunter11 View Post
Look at the graph, one curve has more than double the pressure at the muzzle, yet the velocity is equal, so pressure at the muzzle does not determine velocity.

As you can see , if you wanted to , the velocity curve intersects at that one point for about half a millisecond. The slower curve is still climbing, the faster curve is descending. How long was the barrel ?
As I asked you previously, try and be specific as to just why muzzle pressure is not reliable as a measure of muzzle velocity. I don't require the use of more than one particular powder and barrel length- just as the manuals do for peak pressuure.

If you can't answer that, forget it. It really does't matter anyway..
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  #101  
Old 03-06-2021, 09:16 AM
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Originally Posted by Salavee View Post
As you can see , if you wanted to , the velocity curve intersects at that one point for about half a millisecond. The slower curve is still climbing, the faster curve is descending. How long was the barrel ?
As I asked you previously, try and be specific as to just why muzzle pressure is not reliable as a measure of muzzle velocity. I don't require the use of more than one particular powder and barrel length- just as the manuals do for peak pressuure.

If you can't answer that, forget it. It really does't matter anyway..
It's so obvious, that I can't believe that you can't see it. The muzzle pressure is the pressure at the muzzle, as is shown on the graph.The red curve is showing just over 10,000psi at the muzzle, the blue curve shows close to 30,000 psi at the muzzle, yet both curves result in the same velocity. If the pressure at the muzzle was a true indicator of velocity, then the blue curve would produce more than twice as much velocity as the red curve. It doesn't get any simpler than that. What is similar in both curves, is the area under the curve, but the muzzle pressure most certainly is not even close to being the same.

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  #102  
Old 03-06-2021, 10:03 AM
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Originally Posted by elkhunter11 View Post
It's so obvious, that I can't believe that you can't see it. The muzzle pressure is the pressure at the muzzle, as is shown on the graph.The red curve is showing just over 10,000psi at the muzzle, the blue curve shows close to 30,000 psi at the muzzle, yet both curves result in the same velocity. If the pressure at the muzzle was a true indicator of velocity, then the blue curve would produce more than twice as much velocity as the red curve. It doesn't get any simpler than that. What is similar in both curves, is the area under the curve, but the muzzle pressure most certainly is not even close to being the same.

The blue line,( charge wt.powder and barrel length unknown) certainly appears to be the best one to use in my books. Still can't see why the blue pressure curve, in itself, is not an accurate way to measure velocity.
If the barrel length on that chart were given, it would be much simpler to determine your position as the pressure curve on the blue line is not completed.

As stated in the graphs disclaimer , that is not a real test, just an exaggerated example. I've seen enough of those.
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  #103  
Old 03-06-2021, 10:56 AM
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Not if the bullet has gone only halfway down the barrel. Your riddles are just too clever
Now who would put the muzzle halfway down the barrel? If the bullet stopped halfway down the barrel. there would be o pressure on either side still equal.
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  #104  
Old 03-06-2021, 11:38 AM
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Now who would put the muzzle halfway down the barrel? If the bullet stopped halfway down the barrel. there would be o pressure on either side still equal.
If there was no pressure, how would the bullet get halfway down the barrel?
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  #105  
Old 03-06-2021, 11:42 AM
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If there was no pressure, how would the bullet get halfway down the barrel?
Marksman put it there. Don't you read these posts?
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  #106  
Old 03-06-2021, 12:16 PM
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Marksman put it there. Don't you read these posts?
I appears he just scans a couple of times and calls iit a read. He likes to shoot from the hip in almost every instance . I'm guilty of that myself sometimes, but not to the degree he does. All good anyway. At least he perseveres.
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  #107  
Old 03-06-2021, 08:01 PM
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Now who would put the muzzle halfway down the barrel? If the bullet stopped halfway down the barrel. there would be o pressure on either side still equal.
Did I say the bullet was stopped? In fact the pressure would be very much higher on the chamber side than at the muzzle
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  #108  
Old 03-06-2021, 08:05 PM
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Originally Posted by elkhunter11 View Post
It's so obvious, that I can't believe that you can't see it. The muzzle pressure is the pressure at the muzzle, as is shown on the graph.The red curve is showing just over 10,000psi at the muzzle, the blue curve shows close to 30,000 psi at the muzzle, yet both curves result in the same velocity. If the pressure at the muzzle was a true indicator of velocity, then the blue curve would produce more than twice as much velocity as the red curve. It doesn't get any simpler than that. What is similar in both curves, is the area under the curve, but the muzzle pressure most certainly is not even close to being the same.

He is wrong I thought he was confusing himself but he is in denial
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  #109  
Old 03-06-2021, 09:56 PM
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He is wrong I thought he was confusing himself but he is in denial
Originally Posted by elkhunter11 View Post
Actually the graph posted was correct, it actually proves that his exit pressure theory is nonsense. The graph proves that his exit pressure theory is nonsense, because while the velocity is identical, for both curves, one exit pressure is more than double the other. Of course he and the other individual with not admit that, they will try and come up some other nonsense to distract attention away from the fact that their own graph proved them wrong.

Cant blame him for that. Most would get confused. Its a made up and exagerated pressure profile, as sated in the disclaimer above the graph.
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  #110  
Old 03-06-2021, 10:09 PM
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Once the bullet leaves the muzzle no amount of force will influence its velocity. But if a bullet is losing velocity upon exit and another is gaining velocity it "may" gain a slight velocity advantage simply due to inertia of the bullet mass. But I highly doubt it.
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  #111  
Old 03-07-2021, 12:57 AM
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As I stated earlier the tool to measure velocity is out there it is called a chronograph. We can all afford one that is how we measure velocity. I don't think any of us has the equipment to measure barrel pressures. I don't know why we are discussing it. Quick Load gives pressures but they tell you not rely solely on their info. Every lot of powder is different and every lot of bullets is different. There for there is no certain way to know the pressure your gun is producing from some body elses data. You are only guessing.
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  #112  
Old 03-07-2021, 05:28 AM
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For what it is worth Elkhunter11 is right different powders at the same pressure give different velocities. Salvee your equal resitance is the barrel not the powders pressure curve. When the big companies test loads it is with the same rifle for all the data per bullet weight. Some companies may change primers while gathering their data but very few.
I too thought it was a brass or case weakness problem with the 6.5x55 but I think it is a few weak rifles. Although I have an old Speer manual that has hotter loads in it for the military rifles than the newer Nosler manual has for modern rifles.
I like the 6.5x55 and wish I knew what pressure the modern rifles are to be loaded to. It should by all rights shoot faster than the 260 Rem and 6.5 CM but load data says no. If we look at that though the 270 Win is loaded to 65000 PSI and the 280 Rem only to 60000 PSI. Why they are loaded in the same kinds of rifles on the same case design.
They do publish modern loads for the 6.5x55 its called the 6.5 skan i use it
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  #113  
Old 03-07-2021, 05:40 AM
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As I stated earlier the tool to measure velocity is out there it is called a chronograph. We can all afford one that is how we measure velocity. I don't think any of us has the equipment to measure barrel pressures. I don't know why we are discussing it. Quick Load gives pressures but they tell you not rely solely on their info. Every lot of powder is different and every lot of bullets is different. There for there is no certain way to know the pressure your gun is producing from some body elses data. You are only guessing.
You are right but salavee stated posts back that reality is quickload not facts,check it out, you probably read it too
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  #114  
Old 03-07-2021, 06:55 AM
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You are right but salavee stated posts back that reality is quickload not facts,check it out, you probably read it too
C'mon Marxman, just where did I say that QL is reality ? QL is a great program but I never did say it was reality. When it gets proper inputs, it is very accurate and that accuracy is always eventually verified by my Magnetospeed. So yes, I don't argue with it when I require accurate projections on a new load. To me that makes it a reliable projection... not reality. It's also pretty reliable on muzzle pressures as well. I take it that you and Elk don't use it so I understand your doubts. If that is the case, don't knock it 'til you've tried it.

All I've learned throughout this whole cluster is that I used the wrong terminology. I said "equal pressure equals equal velocity." I should have said "equally applied" pressure equals equal velocity. My error, and I accept the blame for that and will accept the subsequent heat you guys have dished out.
When it comes to reading and knocking, try reading all my posts again. I think you will understand my original question, for which I still didn't get answer, and I think you will see what I was getting at.
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  #115  
Old 03-09-2021, 09:49 AM
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Here's a little note from Brian Litz. Thought you might be interested.



"The 'equal chamber pressure means equal KE' scaling of MV is a general rule, not exact. Certain practical variables in the real world will cause the relation to not hold exactly. Those variables are things like:
1. When you change bullet weight/length in the same chamber, you're affecting the internal case capacity. In order for the relation to hold, when going to a longer/heavier bullet, you would have to throat the chamber out to allow the same internal case capacity.
2. Bearing surface length. Longer/heavier bullets tend to have longer bearing surfaces which take more energy to engrave which affects the energy balance.
3. There are subtleties to the way powder burns in reaction to the time vs. pressure which will affect things too.

Having said those things, the general rule of thumb is still a good rough estimate. In the case of going from 155's to 185's in the Palma gun, let's say you were getting 3000 fps with the 155's. Your expected velocity with the 185's would be: 3000*sqrt(155/185) = 2746. Now if you load the 185's in the same chamber as the 155's, you'll probably fall short of the 2746.

Regarding your Winchester vs. Lapua brass, I would say that when you've matched velocities in the same barrel, that you've matched pressures. Although it's splitting hairs meaning I don't think the difference would be large."

-Bryan
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  #116  
Old 03-09-2021, 06:08 PM
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Do you guys know how many times you could have watched Smokey and the Bandit, and Old School already

I have know idea what my Swedes are running for pressure, the T3 lite is 2880fps with 129g accubonds, IMR 7828 and consistently tight. Iím gonna go watch Cannonball Run.
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  #117  
Old 03-09-2021, 08:46 PM
Salavee Salavee is offline
 
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Elk et al.. here is my issue. Because you emphatically stated, among other things, that the (phoney) graph was correct in all aspects ,plus your attempt to make myself and another member look stupid, your reloading credentials went right with it ..out the window. Here are the facts, so take 'em or leave 'em .

The ratio of the case volume to the expanded volume is called the expansion ratio. Making the peak pressure in the larger volume means more total gas is required, and that greater total gas volume keeps pressure up higher as the bullet continues down the bore, thus accelerating it to higher velocity than the same peak pressure, created with less gas by the fast powder will do. Thus, two powders, one fast and one slow, can produce the same peak pressure, but not the same velocity as was indicated in the velocity/pressure profile.
This is why velocity alone can't tell you what the peak pressure was.Muzzle pressure could ,as it is in direct proportion to peak pressure , bore size and barrel length. As the pressure erosion is constant throughout barrel length, it could also accurately predict muzzle velocity.

It's unfortunate, but your responses seem be in direct proportion to your ego.
You can fool some of the people some of the time, but not all the people all the time.

A number of good folks have left this great forum due to that type of attitude from a few members over the years and that's not good. Put your freak'n ego in your pocket and carry on with some of the good stuff you have gleaned over the years. Really, the subject matter of this thread is not important anyway, contrary to the matter of trying to make others appear inferior to you. That's a major PO to some, myself included,. There are a lot of real good, knowledgable folks on here. You are not the only one.

The mods can do as they like with this post. I can live with it either way, but this post had to happen sooner or later under the existing and past circumstances.

Rant over.
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  #118  
Old 03-09-2021, 08:50 PM
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Do you guys know how many times you could have watched Smokey and the Bandit, and Old School already

I have know idea what my Swedes are running for pressure, the T3 lite is 2880fps with 129g accubonds, IMR 7828 and consistently tight. Iím gonna go watch Cannonball Run.
Canít decide on popcorn or pizza ?
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  #119  
Old 03-09-2021, 09:22 PM
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Canít decide on popcorn or pizza ?
Definitely pizza!.
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  #120  
Old 03-09-2021, 09:30 PM
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