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Discussion starter · #41 ·
What wear? There is no evidence that a 11,000 psi load wears out anything faster.

American ammo is not legal in CIP states.
"Only those firms that have been granted C.I.P. Type Approval can manufacture and market ammunition for weapons with either smooth bore or rifled barrels.
Once Type Approved the manufacturer must repeat the inspection and check tests for each new batch of manufacture.
A Certificate of Conformity is to be issued for each calibre provided that the C.I.P. Standards have been met.
An inspection mark (Proof Mark of the Proof House) is to be affixed to each box of ammunition."

Voluntary atandards are no standards at all. All you have to do is check the number of ammo recalls.
Let's not start down that road, because it leads nowhere. I am ONLY talking about MAP and how it relates to reloads. What American manufacturers do with SAAMI Standards has nothing to do with this subject.

However, if you have some backup for this statement, it would shed some light on the topic of this thread. "What wear? There is no evidence that a 11,000 psi load wears out anything faster."
 
However, if you have some backup for this statement, it would shed some light on the topic of this thread. "What wear? There is no evidence that a 11,000 psi load wears out anything faster."
The only "wear" commonly experienced has nothing to do with assumed chamber pressure: it is recoil with old, fragile guns that can crack walnut stocks. There is no shotgun manufacturer that warns of "wear" with 10-K or 11-K loads vs. 8-K or 9-K loads. There never has been. Excessive bolt speed on autos is often payload-related, not pressure-related.

So, yes, what wear? Rust isn't caused by 11,000 PSI chamber pressure loads. If you want to scratch your bore by dropping steel shot into a lead-only wad, that's not pressure wear.
 
Discussion starter · #43 ·
The only "wear" commonly experienced has nothing to do with assumed chamber pressure: it is recoil with old, fragile guns that can crack walnut stocks. There is no shotgun manufacturer that warns of "wear" with 10-K - 11-K loads vs. 8-K or 9-K loads. There never has been. Exessive bolt speed on autos is often payload-related, not pressure-related.

So, yes, what wear? Rust isn't caused by 11,000 PST chamber pressure loads. If you want to scratch your bore by dropping steel shot into a lead-only wad, that's not pressure wear.
Thank you, Randy
 
That is not what you stated before, this is your statement "Why ride the edge when there are perfectly good options that do not."

My statement is MAP is not an edge. There is nothing wrong with your use of a lower pressure round, but there is also nothing wrong with a load at or approaching MAP. The difference between the wear rates of the two different pressure levels is tiny and most likely unnoticeable.
Some years ago, a shooter was shooting trap at a local club. He was using a Winchester 101, with reloads. His gun burst and a piece of the receiver hit the shooter next to him in the head, killing him. Those reloads were checked and were all within specs. Hard to explain. Could it have been a gun that was stressed over time? When I reload, I always look for a load that is productive, at less than maximum pressure. I do this for rifle and handgun ammo as well. I do not see where it causes any issues.
 
Discussion starter · #45 ·
If two thousand PSI (within MAP) is the difference between a shotgun exploding and not exploding, why would anyone ever use that shotgun?

No one will probably ever know what caused the terrible accident that happened at your local club, but it isn't the difference between 8,000 PSI and 11,500 PSI. Tom Armbrust ran a Super X barrel to 50,000 PSI before it failed and the failure was a split, not an explosion.

Shotguns are very stout, unless there is an obstruction in the barrel and that has been proven any number of times, even with damascus barrels.
 
CIP run 2 tier proofing,
for 12gauge its 740bar or "1050bar HP"
That HP stands for high performance.


This is the post i wrote.

Its not hard but different.
 
1050 BAR is written right on the side of several shot shells.... mainly 3-1/2" duck and goose type shells.
but it's pretty clear.


anyway i don't comprehend this whole conversation.
average,,, is what we done in third grade math class.
average,,, is what we done in third grade math class.
That's the problem with American math education.
What is the problem with using the average (mean) compared to other measures of center?

The average is highly susceptible to OUTLIERS. It's almost unique that way.

Let's look at some pressures: 14, 15, 14, 13, 6, 14
The Average (mean) is 12. Does is look like 12 is a good number to tag that batch with? NO!
The MEDIAN is 14. Does 14 look like a good representative of the group? YES!

The Average is highly susceptible to "outliers", in this case, the blooper at 6. The only advantage for Average: it's easy for 3rd graders to calculate. Really. Grown-ups use computers or calculators to describe measures of variation better.

As you read the SAMMI standards, how the range of values is 'restricted' is deep statistics. That blooper at 6 is allowed if statistically rare enough. SAAMI is for factories making thousands of shells per hour. We are interpreting them for home use.

I taught first semester college AP statistics and have a math minor and degree in physics. I don't understand everything about MAP. The data restrictions are hairy! This stuff process engineers study in college.

For me, I can simply that by keeping my maximum pressure for EVERY shell under a nice safe value.

If I can make a shell for less pressure that is just as good for the job I need to do, that's my choice.

If I felt the need to run 15,000 psi shells in my 20 gauge, I would pick up my 12 gauge and run 11500 psi instead.

Its nice to know my brand new, proof tested 20 might be able to handle it. But unless they are factory loads... I'll just use the bigger gun.
 
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Add a zero at the end of the pressure and you would be fine. ;)
About 30 years ago, I was safely hot-rodding .45 Colt and .30-30 Winchester in firearms that I determined this to be safe with. But I was always nervous. After a while, I wondered why I was trying to push 30-30.

The danger: if some of those shells that were safe in my new stout Marlin found their way into a Winchester. Bad.

Then I realized I .. .um... had a perfectly good 30-06 in the gun safe. I could load DOWN and get the same result and zero worries. It was fun learning new things, so I don't regret it.

The hotrod .45 Blackhawk is now a .44 Mag Blackhawk. Same thing.. just... no longer keeping hot .45 LC around.

I imagine that's why we keep a lower pressure for shot shells as standard. Since we don't proof guns in America, you never know what is out there.
 
Discussion starter · #52 · (Edited)
After reading through some of the stuff here......who cares about the metallurgy of a shotgun? This thread is about ammunition only.

As a reloader we don't get to use MPLM or MPSM.

Mission Statement? It is listed under 'About SAAMI' on their web page. This thread has nothing to do with their mission statement. You will no doubt be unsatisfied anyways.

Why MAP, really? Why do you think MAP was established? Take a wild guess! MAP is set just like every other service limit placed on every piece of engineered anything. From automobiles, planes, jet engines, steel beams in buildings etc., all that stuff has service limit maximums in one form or another. Shotguns are no different, after all they are really just open ended pressure vessels. Why do compressors kick off at a certain PSI? Maybe because they reached their tanks' service limit? Do you think the actual maximum pressure where the tank will blow-up is 2 PSI over that? I shouldn't be surprised, I suppose, but with all the engineers that are supposedly here, come on.

As usual K.I.S.S. and common sense are never part of the conversation.

I should have known better. I keep hoping....

Moderators, in the future, IF I ever start another thread like this, just delete it and save me from my stupid self. Thank you.
 
All I can say is that reloading is a very serious business. With powder availability being what it is, many reloaders are trying different powders. I would never encourage any reloader to push any kind of limit. If you can't find a load at moderate pressure that works for you, keep looking. I had a young customer that started off reloading and liked to "play around" with loads. he eventually blew up a cheap single shot 12ga shotgun. We had the parts mounted on a board, but the customer had some PTSD from the incident and quit shooting. Don't ever load from an open can of powder and never shoot another man's reloads. Too much to risk, please stay safe.
 
Discussion starter · #54 ·
All I can say is that reloading is a very serious business. With powder availability being what it is, many reloaders are trying different powders. I would never encourage any reloader to push any kind of limit. If you can't find a load at moderate pressure that works for you, keep looking. I had a young customer that started off reloading and liked to "play around" with loads. he eventually blew up a cheap single shot 12ga shotgun. We had the parts mounted on a board, but the customer had some PTSD from the incident and quit shooting. Don't ever load from an open can of powder and never shoot another man's reloads. Too much to risk, please stay safe.
The intent of this thread has NOTHING to do with people doing stupid things. Simply a thread to discuss MAP. MAP is not dangerous, never has been, never will be. Comments like you have posted only continue the BS associated with MAP. Loads at or under MAP are not a problem.....that is not an opinion that is fact and you can ask whoever you want in the industry about it.
 
The intent of this thread has NOTHING to do with people doing stupid things. Simply a thread to discuss MAP. MAP is not dangerous, never has been, never will be. Comments like you have posted only continue the BS associated with MAP. Loads at or under MAP are not a problem.....that is not an opinion that is fact and you can ask whoever you want in the industry about it.
The issue is that some people, without a background in reloading, are loading now. Some of them visit this site. I have been asked in the store if the rifle powder they have will work in shotguns! Comments get misconstrued. I advise people to stick EXACTLY to the recipe published by the powder companies. I guide them towards loads that are not near top pressure.
 
Discussion starter · #56 ·
The issue is that some people, without a background in reloading, are loading now. Some of them visit this site. I have been asked in the store if the rifle powder they have will work in shotguns! Comments get misconstrued. I advise people to stick EXACTLY to the recipe published by the powder companies. I guide them towards loads that are not near top pressure.
That's an issue for another thread. It has nothing to do with this thread.
 
The SAAMI definition of Standard Deviation (σ, the letter Sigma):
Standard Deviation (σ) - The Standard Deviation for each Maximum Average Pressure Level is
based on a Coefficient of Variation of 7.5%. This 7.5% Coefficient of Variation is maintained
throughout the SAAMI pressure spectrum providing a realistic Standard Deviation for each pressure
level. To obtain the Standard Deviation for a particular MAP multiply the MAP by 0.075 (i.e.,
12,000 psi x 0.075 = 900 psi).
The problem I see here is that this is not the definition of σ (Standard Deviation) at all. It is thus an arbitrary construct masquerading as if being a Standard Deviation. That is not at all to say that there isn't beneficial merit in it, but merely to point out that they are playing with terms that they merely redefine on their own terms. When I ponder why they might do this, a famous quote by W. C. Fields comes to mind.

The actual definition of 'one' σ ('one' Standard Deviation) in a verbalized form is:
The square root of the sum of the squares of each of the individual test samples deviations from the mean.
It seems quite sloppy of the SAAMI to quite intentionally distort and thereby confound terms that are actually straightforward and simplistic. What appears to be happening is not at all "a realistic Standard Deviation for each pressure level", but rather an arbitrary assignment of +/- 7.5% to an arbitrarily chosen MAP.
 
Discussion starter · #58 · (Edited)
The SAAMI definition of Standard Deviation (σ, the letter Sigma):


The problem I see here is that this is not the definition of σ (Standard Deviation) at all. It is thus an arbitrary construct masquerading as if being a Standard Deviation. That is not at all to say that there isn't beneficial merit in it, but merely to point out that they are playing with terms that they merely redefine on their own terms. When I ponder why they might do this, a famous quote by W. C. Fields comes to mind.

The actual definition of 'one' σ ('one' Standard Deviation) in a verbalized form is:


It seems quite sloppy of the SAAMI to quite intentionally distort and thereby confound terms that are actually straightforward and simplistic. What appears to be happening is not at all "a realistic Standard Deviation for each pressure level", but rather an arbitrary assignment of +/- 7.5% to an arbitrarily chosen MAP.
That's an issue for another thread. It has nothing to do with this thread. Regardless of what "number" they use for the Sd, whatever slight change that it makes to the actual Sd, it has nothing to do with damaging a firearm when you have a load at or approaching MAP. As you still would be thousands of PSI away from the point of damaging a firearm.
 
So, if I understand all of this, SAAMI MAP is +/- 7.5% and is intended to give manufacturers a minimum standard to build to. Some manufacturers may build to MAP and others may build to 3x MAP which presumably is the difference between a $700 O/U and a $4,000 O/U.
 
Discussion starter · #60 ·
So, if I understand all of this, SAAMI MAP is +/- 7.5% and is intended to give manufacturers a minimum standard to build to. Some manufacturers may build to MAP and others may build to 3x MAP which presumably is the difference between a $700 O/U and a $4,000 O/U.
Depends on what you mean by 'build to'. If you mean service pressure Yes, if you mean overall strength of a shotgun, No.
 
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