The New King

[tommac919]

And with all of above, for same $, I'd buy 3 glock 20s before a Coocan

In my experience, they hold up just fine and it' the same bullet.

[sqlbullet]

So, the real king comes into play in this discussion...Physics.

The same physics that allow a 45 ACP +P to get to 950 fps and 460 lb feet of energy with a 230 grain JHP at .160 sectional density allow the 10mm to do the same thing.

To keep the sectional density the same in the smaller bullet, the weight falls back to 180 grain JHP, velocity goes up to 1070, but pressure is right around 23,000 psi and energy is 460 lb feet.

Physics gives no one a free lunch.  But by the same token, it treats everyone fairly.  Given a pressure, and a straightwall case, you can accurately predict that different diameter bullets will deliver about the same energy at the same sectional density levels.

If you are (un-necessarily) worried about full power 10mm loads in your favorite guns, download except when you need it.  Like shooting 38's in your 357.  But, unlike some of the small 357's that shoot apart in short order if subjected to a steady diet of full power loads, all the reputable 10mm makers have guns that handle the power just fine.

The 1911 is often the target of allusions that it won't take the stress.  Others point to cartridges like the 38 Super as an example of a high pressure cartridge that works just fine.  Both 45 ACP +P  and 38 Super place about 3,600 lbs of force on the slide during firing.  This occurs at peak pressure while the barrel and slide are locked together*.

The 10mm does ramp this up, to about 4,700 lbs.  That is an increase of about 33%.  But, that force is exerted through about .145 sq in of slide area around the ejection port.  Carry the 9 and you get about 32,500 PSI of force being applied actual steel in the slide.  4140 ordnance steel has a yield strength of 60,000 psi.  416R Stainless is lower at 40,000 psi fully annealed.  Depending on the hardening process used it can come close to ordnance steel.  I assumed a conservative 50,000 PSI yield, though I suspect it is hardened more than that by most manufacturers.

Since this is yield strength in steel, we just have to worry about not exceeding the value.  So how hot would we have to get before our slide might be damaged?  About 58,000 PSI and a stainless slide might start to stretch if it were fully an.  Carbon steel slides are fine up to loads of nearly 70,000 PSI.  A 10mm proof load max's out at 54,000 PSI.  A steady diet of proof loads in your Ruger SR1911 might be a not great idea, but it will handle full power ammo fine.

What about fatigue?  Fatigue is pretty linear.  Your 10mm has about 1/3 less slide life than a 45 acp 1911.  Since Colt figured out slide hardening during WWII a properly made slide is good for 100,000 rounds in 45 ACP.  So, figure your Ruger, Delta Elite, Kimber, Dan Wesson or any other 1911 will run about 60,000 rounds before you have to worry about the slide.  That represents an ammo cost of about $8,000, compared to about $500 for a new slide, barrel and fitting work.

*About frame battering.  A typical 1911 slide weighs about 14 oz and hits about 25 ft/second velocity in 45 ACP.  This works about to about 60 lbs of force on the slide when it stops at the back of the gun, assuming your can hold it like a vice that barely moves.  The more you move, the lower that number.  10mm is gonna increase that by about 30% as a result of the higher pressure impulse.  That puts us at a max of 80 lbs, again assuming you have a vice like grip.  For most of us mortals that value will be lower.  Compared to the 4,700 lbs of force the slide contained at peak pressure, hitting the frame is nothing.  Like literally less than 2% as much force.

The role of the recoil spring is to provide the needed force to propel the slide back forward, pick up a new round and get the slide into battery ready to shoot.  Along with that in the 10mm we use it to dump some slide velocity to just slow things down a bit.  This is NOT to mitigate any force.  It is to give other slower moving assemblies time to do their job (looking at you magazine and magazine spring).  I often find that +10% magazine springs doe more for 10mm reliability than a a 24 lb recoil spring.  The recoil spring is just trying to slow the slide down enough that the magazine spring can get the next round presented and ready to load.  Adding some oomph to the mag spring does the same thing by increasing the speed that round gets into place.

I haven't handled nor do I know any of the specs of the new Coonan.  But I do know the 1911 is plenty strong enough for the 10mm.   

--Edit...I measured my Witness.  There is less slide height in the witness, but the slide walls are a good bit thicker than a 1911 slide.  Result in about the same amount of steel in cross section...Maybe a bit more.

[Scarlett Pistol]

Following for the physics discussion.

[Intercooler]

Yea... That was a scientific piece 

[sqlbullet]

Just don't check my math too close or show it to my old physics professors.  I am sure they would shred me.

I got to thinking this morning more about this, and realized I forgot to account for the "cork in the bottle".

The brass case walls expand under pressure.  This does two things.  First, it seals the breech.  Second, it locks the brass in place like a cork in the bottle.  Cartridge brass has a yield strength of between 11,000 psi fully annealed and about 65,000 psi fully work hardened.  The heads of Starline brass tend to be on the "softer" side, so figure about 15-20K psi.  Up to that pressure, the breech is sealed just by the case head.  Above that, the case head tries to stretch, putting stress on the barrel/slide interfaces.

This means we can deduct about 10-15K psi, maybe a bit more, from what actually reaches the slide.

[The Earl o Sammich]

That looks like a Glock that blew up.  You know what they say about Glocks....

My Colt Delta Elite has at least 500 rounds through it an is hammering fine.  I would call that the king.  Although I do like this Tanfolio, Witness Elite Match.  Much more capacity and I can hammer them faster down range ( weighs a lot).

[sqlbullet]

That Glock that blew up looks like it had an aftermarket barrel installed too.

[SA4044]

I will just leave this here

I shot one of those at The Range in Austin a few months ago. No issues at all with it shooting S&B 357 loads. I shot a 50 round box and did not have one malfunction. Mine you it's a rental gun there but The Range takes good care of their stock/rentals. If was a ton of fun to shoot and I'd do it again.

[Scarlett Pistol]

If it was built for 357 Magnum the dimensions line up that it could be chambered for 10mm magnum. Is this correct, at least in theory? From the case length and cartridge length for both cartridges it seems viable...

[Canoe]

Coonan apparently briefly made a 41 mag version so a 10mm mag may not be out of the question.  However, given how briefly the 41 version was around, suspect the gun was not up to the challenge.

[Scarlett Pistol]

Dang.... I'd be saving my pennies for a 10mm magnum or 41 magnum version. I may give them a call and see if they'll be honest about what caused them to stop offering the 41 magnum version.

[Canoe]

Dang.... I'd be saving my pennies for a 10mm magnum or 41 magnum version. I may give them a call and see if they'll be honest about what caused them to stop offering the 41 magnum version.

I'd be curious to see what they say.  Suspect you would need a bigger platform than the one used for the 357 in order to use the 10mm mag to its full potential but I really have no idea.

Incidentally I called them when I was trying to fine tune mine to shoot some standard power 38 specials.  Super friendly and helpful.  They patched me right though to one of the head techs (Ray, if I recall) and he spent 30 mins giving me the low down on everything.  Hard not to love a company that offers a cool product and backs it up with solid friendly service and support. 

[PCFlorida]

You are right about that. I had some questions about my GP40 and called Eagle Imports. A woman answered the phone and I mistakely thought 'Oh boy'.

She told me they were not importing the front sight I was looking for but a CZ-75 would work for me. And it did.

[THUNDERMAN]

Pretty sure my sig 220 is a king also. I have put 600+ rounds thru it and not one malfunction of any kind. Over 2/3 of these have been stout handloads of various gr bullets. It may not hold as many rounds as some and be heavy but it rules in my opinion.

[PCFlorida]

Pretty sure my sig 220 is a king also. I have put 600+ rounds thru it and not one malfunction of any kind. Over 2/3 of these have been stout handloads of various gr bullets. It may not hold as many rounds as some and be heavy but it rules in my opinion.

Yes, that duplicates my experience, it is a great 10mm.