The 10mm has a branding problem.

   It's a great cartidge, but it hasn't caught the mass of the people's attention. The name "10mm" made sense in the mid 80's when the 9mm was growing in popularity, but now it doesn't mean anything to most people.

   I suggest we rename it .40 Automatic Magnum. That is what it is. It is a .40 automatic lengthened just a touch and loaded to much higher pressures. The rename will make the cartridge's potential intuitively obvious.  The phrase "Always use a cartidge starting with a 4." leaves people uncertain about the 10. If lazy people call it the auto mag, I'm OK with that.

   The other problem is that there doesn't seem to be a pressure standard tied to it. We refer to the original Norma loads that put a 170 grain pellet out at 1400 fps or a 200 at 1200. The Silvertip used to be quoted at 165gr at 1265.  We need a maximum pressure standard to define a useful magnum load to differentiate it from the .40 S&W. I propose 40,000 psi. A touch more than a .357 Mag but less than a .44 Mag or .41 mag.  This would protect us from manufacturers reducing the power of the 10 to a .40 S&W and making full powerful ammunition unavailable and a legal liability. Any other pressure nominations?

DAB



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The 10mm is what it is as developed...to rebrand it to a 40 something would derate it in my humble opinion!  That's where those of us who have enjoyed the ballistic potential of the 10mm cartridge, have beat on the 40 short & weak, when it made its appearance.  The true enthusiast have tried to educate people about the existence and performance that the 10mm brings to the dance!


The 10mm is what it is...The PERFECT 10!

Wrong!!
The 10mm came first.....if the 40 came first I would agree with 40 mag
Thus 40short & whimpy

Quote from: RVL on November 30 2013 11:13:38 AM MST
   
   The other problem is that there doesn't seem to be a pressure standard tied to it. [...] I propose 40,000 psi. A touch more than a .357 Mag but less than a .44 Mag or .41 mag. 

Wiki shows 37,500 psi as max pressure for 10mm.  Don't know if they're right.  They also show .357Mag  to be 36,000 psi, the same as the .44 Mag that they show.  They don't give a pressure for the .41 Mag, but Underwood (as far as I recall) has a higher energy .41Mag round than their .44Mag.  Also, Underwood has a .357Mag load with about the same energy as their 10mm ... that would seem to imply a higher pressure for the .357Mag, unless they manage to keep the pressure from dropping as fast as the bullet moves down the barrel.  (That Underwood .357Mag load DOES have a LOT of flash and muzzle blast, so that supports the guess that the pressure stays closer to max longer).  BuffaloBore has a .357Mag with substantially more energy than a 10mm ... I REALLY don't know how they do that.

Most of the time 357mag needs a 6in barrel to chase down max load 10mm power.

Historically, the .357 started out with a 158 gr pellet moving at 1500 ft/s in the 1930's. My old Speer #11 manual gives 46,000 CUP. More or less psi with engineering factors that smear out the definition. It says 1349 ft/s over 13.0 grains of Blue Dot.

Speer gives 43,500 for the .41 Magnum and also 43,500 for the .44 Magnum. The SAAMI loading seem to decline over time unless met with resistance.

The original Norma loads for the 10mm were 1400 ft/s for a 170 grain and 1200 ft/s for a 200 grain projectile. I fear, specifically, that certain guns - coughwitnesscough - may cause the ammunition to be downgraded to the point where we might as well be using the short and week. I would love to know the old Norma pressure loads to give a nominal figure for the .40 Automatic Magnum.

Ying Ko, You show the original full power loading as Nuclear in Red. Are you indicating that such are too powerful or beyond the pale?  Such is the downgrading I fear. I also have been sneered at and told 'Never bring a gun that doesn't statr with a four." This was said by a man with a .40 S&W!

My Caspian 6 inch longslide is made for the full power loads.

Macc283, Of course you are right. The 10 mm came first. I was just describing the cartridge in a manner to convert .40 S&W shooters. Moreover, the greater case capacity leads to lower chamber pressure on equivalent loads.

DAB

I think the cough is in the wrong direction. More like coughDeltacough.

Touche'

Of course that is why we must establish a nominal power level that the guns are made to. The 1006 and the Glock are built like tanks. I added an inch to my 10's slide not so much to gain velocity as to gain mass to slow slide velocity.

DAB

RVL, Intercooler has run some of the most potent rounds ever from his EAA guns and is documented.

Now I will say this and mentioned it the other day in a post.  Back when SAAMI was reevaluating things and the pressures started to be measured with newer piezoelectric transducers instead of the older Copper Crusher Method.  Things took a turn and 10mm was one that changed from a CUP measurement (never officially set), to 37,500 PSI standard we see today.

Under this reevaluation many previous established loads were changed for several cartridges, including 357 magnum.  This is when Alliant issued the Blue Dot warnings for 357 magnum and 41 magnum.

There is no direct correlation of CUP values to PSI values in most cartridges...http://www.shootingsoftware.com/ftp/psicuparticle2.pdf

More info here at ChuckHawks http://www.chuckhawks.com/pressure_measurement.htm

Nope!!!!  Its a 10 mil.

I think it may be good to do a std, +P, +P+ system like what is showing up for the other handgun loads.  That way the manufacturers of the handguns will have incentive for building to the higher standard.  They could do worse than breaking them at the: --- Medium = SAAMI,  ----Full Power = +P,  -----Nuclear levels = +P+,  as Shadow shows in the chart.

The other thing is the fright of thinking the recoil will rip your hand off if you shoot one.  The simple fact that the automatic action soaks up so much of the recoil that shooting lighter handguns with 10mm rounds is not only possible, but a load of pain free fun to boot. 

Greg

Quote from: The_Shadow on November 30 2013 08:09:00 PM MST

Under this reevaluation many previous established loads were changed for several cartridges, including 357 magnum.  This is when Alliant issued the Blue Dot warnings for 357 magnum and 41 magnum.

I haven't been able to find any previous posting on the forum about the above information.  Anyone have a link (to a posting on the forum, or elsewhere)?

I can't give a specific link...But it is known that the change over from the Copper Crusher method (still used by some companies for specific test) of pressure testing has shifted to the electronic age using piezoelectric transducer and strain gauge measurement systems.  Some are directly acted on and others are indirectly acted on to formulate pressure readings.  These newer test allow for faster results and data collection.

However over time powder companies and handloading manuals have changed, because reevaluation, new powders, bullet and cartridge additions but more recently corporate lawyers.

Couple of comments.

First, the copper crusher method didn't measure pressure in PSI.  I measured in CUP - copper units of pressure.  There is no way to correlate CUP to PSI.  PSI measures actual pressure over time, where CUP measures the effect of pressure, independent of time.

Imagine, for a moment, a block of clay.  Imagine you press a steel plate against the clay at a moderate pressure for 1 second, versus the same pressure for 5 seconds.  The clay will deform more the longer the pressure is applied.  This is how CUP works.  A copper pellet is exposed to the entire pressure event, and it's distortion is measured.

The older Speer manuals almost certainly are reporting pressure in CUP, not PSI.

Using modern piezoelectric measurement tools, we get to see the actual pressure over time.  When this testing came into play, SAAMI switched to using PSI instead of CUP.  Unfortunately, the absolute values of the two systems fall into comparable numeric ranges.  This has lead to many people thinking that SAAMI has "downgraded" pressure ratings, when that is NOT in fact the case. (Although SAAMI has downgraded some cartridges, such as the 38 Special, in order to ensure ammunition is safe for very old firearms.)

Augmenting this belief is the fact that some cartridges have a higher SAAMI PSI rating then CUP rating.  The 45 ACP, for example, when from 19,000 CUP to 21,000 PSI.  And the 30-06 went from 50,000 CUP to 60,000PSI.

Further, warnings issued by powder manufacturers at the same time clouded some understanding.  The reason for these is the new testing they did.  CUP pressure testing is tolerant of extreme pressure spikes as long as their duration is very, very short.  They aren't noticed as CUP doesn't correlate to a time index.  PSI, however, does.  In this testing to certify their loads under the new method, they discovered that certain loads had such spikes in certain circumstances.

The result of the change is safe, better, and best of all more consistent load data.  Consistency is the key to accuracy, and all the power in the world does no good if you don't hit the right spot.  Although some loads are reduced by small amounts, the ammunition is better.

tl;dr:  PSI?CUP, and can't be reliably compared.  The numbers of each scale don't relate to each other, and the change wasn't a "down-grade" in performance.

Second, 10mm does have a pressure spec.  It is 37,500 PSI MAP. 

MAP is maximum average pressure, or the average highest pressure peak of 10 rounds.  Due to small sample size, it is possible for larger samples to exceed the MAP value and still be considered in spec.  In general the SAAMI MPLM will be no more than 2.5% higher than the MAP.  In addition, the standard allows for MPSM of 6.3% over the MAP, and an extreme variation (MEV) of a single cartridge of 20.6% over MAP.  This means in a lot of say, 10,000 rounds of 10mm, you should see that majority of the 10 round samples average 37,500 PSI, with no 10 round lots averaging above 39,862.5 PSI, and no single round exceeding 45,225 PSI.

Similar deviation of lower pressure would be also unacceptable, but not unsafe.

Third, lets all remember that +P is a designation SAAMI spec ammunition, loaded in a case that has the same external dimensions as another cartridge, eg, a higher pressure version.  It doesn't mean, a little hotter than spec.  38 Special +P is 3,000 PSI MAP higher spec than 38 Special (20,000 and 17,000 PSI MAP respectively), and 9mm +P is 3,500 PSI MAP higher than 9mm Luger (38,500 vs 35,000 PSI MAP).

+P+ is not a spec that is recognized by SAAMI, and has been used by mfg's to designate ammo that exceed SAAMI spec.

With this understanding, the only application to 10mm would be +P+ since +P is a recognized SAAMI spec that does not apply to 10mm.  The loads on Shadow's table in the 700 ft lb range might exceed SAAMI spec, and therefore might be +P+, those that exceed 750 lb-ft probably exceed SAAMI spec and therefore are probably +P+.

All that said, to the OP's point, the 10mm is really not well recognized.  That is not to say that it has a negative image, which would require a re-brand possibly.

It just needs better exposure.  Invite a friend, make a post, evangelize (accurately) the strengths of the cartridge.


edit:  References

http://www.handloads.com/misc/saami.htm

http://en.wikipedia.org/wiki/Copper_units_of_pressure

http://kwk.us/pressures.html#stats

Quote from: sqlbullet on December 02 2013 10:08:05 AM MST
[...]
In general the SAAMI MPLM will be no more than 2.5% higher than the MAP.  In addition, the standard allows for MPSM of 6.3% over the MAP, [...]
[...]

Thanks for that post ... very useful and informative.

I don't think you specifically defined MPSM ... what does the acronym stand for?  Maybe "max pressure small_lot"?  From your example, I THINK the definition must be "max pressure averaged over any group of 10" ... is that right?

I also noticed that, in your examples, that the max force on a .45ACP bullet, vs the max force on a 9mm bullet, when each of them are right at their spec max pressure, is slightly less for the .45ACP.  I continue to be perplexed about the fact that .45ACP is widely regarded as being much superior in "single-shot-stops" than 9mm.  Assuming that that perception is correct, it would seem to be possible only if the .45ACP bullet experiences a much higher AVERAGE force in its complete travel down the barrel, even though the max pressure is slightly less.  That conjecture is based on "single-shot-stops" being largely correlated with muzzle energy, but maybe that's not true.  (The reputation of .45ACP even goes farther: many people regard the .45ACP as a better "stopper" than .40S&W, and that's even harder for me to understand).