[ARCHIVED THREAD] - Handgun power limitations (Page 1 of 2)
Posted: 3/5/2008 8:26:10 PM EDT
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I was wondering if anyone knows what limits a typical handgun to its present power. For example, why can't a standard 9mm cartridge be loaded with more powder such that it has the equivalent ballistics to a .357 mag? Is it because there is not enough room in the cartridge for enough powder (volume limited) or is it simply because the materials used in typical handguns are not strong enough? To put it another way, if we hogged a barrel out of a 1 foot diameter solid steel cylinder, chambered it for 9mm and made a very strong bolt action, could a 9mm cartridge be loaded to much higher velocities? |
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I do know that Brian Enos said in his book that 38 super major loads are unpleasant to shoot, even with a compensator, in a 36 oz gun. 9x25 Dillon is even worse. If you want to shoot at these power levels, you'll need a heavier gun, which brings up problems with handling quickness and carry comfort. So even if you could, you wouldn't want an overpowered 9mm Luger. |
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Pressure. Actually peak pressure limits how much propellent a cartridge can take. Case capacity limits the lower burning rates, peak pressure limits the highest burning rate. Most firearms are FAR stronger than the cases fired in them. Glock is an exception as I have seen these barrels rupture. |
Most of that recoil is from the mass of the propellent. While the bullet is in the barrel, propellent mass is moving about half the bullet velocity, on average. Once the bullet exits, the propellent mass accelerates to over 4000 feet per second in the magnum pressures of a handgun. |
I thought the increased recoil was a simple matter of the increased acceleration of the bullet to higher energy levels? Even with a compensator that keeps muzzle flip at zero, 9x25 is still a wrist breaker. And I only posted that to demonstrate that a 124 grain 9mm bullet at 1600 fps would be undesirable even if possible. |
How about 147 gr at 1350 fps (aka: .357 mag)? |
Not in a pistol. One truth is pressure equals temperature. Barrel erosion is a problem when pressures are over 45,000 PSI and sufficient duration at that pressure causes the innermost layer of barrel steel to heat to above the transition temperature for that alloy. Under 25,000 PSI, barrels last forever. With any auto pistol round loaded to maximum SAAMI pressure, you will wear out the slide before the barrel erodes. Want to erode a barrel? Try a .22-243 Middlestead. 5000+ FPS is possible with light bullets. 30 grain bullets with 55 grains of propellent. Probably gone in under 500 rounds. |
Recoil is conservation of momentum. Compensators work by diverting some of that propellent momentum up. Most pistol comps do nothing to offset recoil, to do so would be punishing to the shooter in blast. But .50 BMG rifle compensators do exactly that, the longer barrel keeps the danger zone away from the shooter (but not bystanders or tail light lenses on your Ford truck if you are stuck on stupid) |
.45 ACP? |
Yep. Sierra has a test barrel for their NM bullets they furnish to LC. Legend has it this barrel has over a million rounds though it with no noticable erosion...or loss of accuracy. Per contract stipulations, they must accuracy test each lot of bullets shipped, doing so for 35+ years adds up. It is a Universal Receiver too, meaning MANUAL LOADING. And .22 LR? Some junior program target rifles have well over a million rounds through them, no complaints in accuracy as they will clean frames with all X-ring. That is why junior smallbore has 5 round frames, the targets would be shot out. I have a few cleans back in the day...standing. 4X is my best but still a full 50. |
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Usually they are relieved in some manner. Heating then cooling. Ruger and Remington both hammer forge rifle barrels and no once complains about them splitting. I think Glock barrels fail because they cut an extra 1mm from the .40 barrel in order to get a bigger round into it than it was meant to hold. |
Thanks for the help Dave. The glock worship started getting strong here... I have seen overloaded 1911 blow the case to pieces but the barrel kept its original shape. I have also seen squib loads where the shooter racked the slide and fired a normal round behind it. Again, brass vaporized but this time the link broke, the slide went forward and the barrel up. But a new link, new grips and replacement underwear for the shooter was all that was necessary. I've shot 200 grain JHPs from my Super at over 1200 FPS. With 10+ grains of powder pushing it, there was a bit of recoil. |
Yep. 'Cept it it a half a millimeter. But it counts. The CHAMBER fails. |
It's a millimeter in diameter, half mil radius. |
Great. Now we have to worry about idiots using HX as propellent. For the unknowing, HX in any cartridge is bad juju. Powder BURNS. Deflagrates. It does not detonate. HX would shatter the firearm. |
Yes. Usually not a concern, but if you're trying to get the velocities I have seen thrown around here, volume is a problem. |
So putting all of this together, the 9mm round has too little volume to load enough powder to throw a 147 gr bullet at 1350 fps. If a more energetic powder could be used, the limited volume might increase pressures to above the pressure that causes barrel erosion. This is why rounds like the .357 Sig increase the cartidge volume. So, aside from the mechanical limitations of pistol design, a 9mm could be loaded to yield .357 performance if: a) a more energetic powder was created, and b) a barrel material that could withstand higher temperatures before eroding were used. Correct? |
a) No, Powders are nearly equal in energy but differ by burn rate. b) Barrel erosion isn't a problem in auto pistols. Or most handgun rounds, save oddballs like .357 Maximum, .454 Casull and the like. Temperature is a function of pressure. Erosion is a function of temperature and duration at that temperature. |
So erosion is a function of pressure (since pressure is a function of temperature and burn rate). As I understand it, if a barrel was made out of something that could handle the higher pressures/temperatures then higher pressures/temperatures could be used. Thus, the 9mm cartridge could be loaded with more powder or more energetic powders...approaching .357 mag performance. What I am getting at here is that rather than increasing the cartridge volume (like .357 Sig) which reduces the carrying capacity of the magazine, making the barrel out of a higher temperature alloy would buy you the same performance. |
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The maximum pressure allowable is limited by the CASE and PRIMER, not barrel strength. Most 9mm loads are nearly compressed, to increase pressure, faster powder must be used BUT the pressure rise is neither uniform nor predictable/repeatable. Hornady sells a special line of ammo called "Light Magnum" which brings a little more performance without an increase in pressure. This isn't possible with 9mm, you get SAAMI limited rounds or you get + pressure, also limited by SAAMI. Or you can try to get +P+ but it won't get anywhere near .357 Sig etc. Case capacity limits performance, plain and simple. Why else would Remington try to introduce a stretched .357 Mag in the .357 Maximum? More powder means higher velocity. Now with the .45 ACP, the much lower pressure can be improved a great deal with stronger brass and a suitable pistol...this is called the .45 Super and offers a great deal of performance at lower pressure than 9mm, still much higher than SAAMI .45 ACP. 200 grain JHP at 1250 FPS goodness. |
No help. Steel used for cases is a soft, deep-drawing type that offers no benefit in strength. And primers? Have to be soft enough for the firing pin to dent with a specific energy. Why do you want to make a magnum out of 9mm? Get a .38 Super if performance is your yen. |
9mm isn't all that bad in a subgun platform.. Infact I am having a 16in barrel made for my semi-auto PPSh-41 so I can run 9mm through it 
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I am just looking for the real engineering reasons that limit handgun performance. Trying to advance the state of the art, if you will. I am not necessarily stuck on the 9mm cartidge, I am just using it as an example. I think everyone would agree that if a handgun could be produced with 9mm capacity, but .357 performance, it would be an improvement (ok, some people would disagree, but the majority would agree  ). The same technology could improve the performance of other calibers as well.
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Hate to burst your bubble but peak pressure happens in the first 4 inches of the AR15 barrel. Barrel length has very little to do with peak pressure. In most pistol rounds, peak pressure happens a few millimeters down the barrel from the case. |
Every ammunition manufacturer has tried. A few sell higher performance loadings like Hornady but in pistols, that is limited to +P in the few calibers that allow it like .38 Special, .45 ACP and 9mm. Some rifle calibers like .257 Roberts also have an SAAMI +P rating. |
The case is the seal. Caseless ammo requires an infintely reusable seal. The G11 operated under 58,000 PSI. Quite normal. The problem with this is the chamber now receives a lot more heat and is prone to cook-off even though the propellent on the caseless ammo had a much higher autoignition temp than conventional. |
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If it can be done with 9mm, it is probably here: cartridgecollectors.org/intro9mm/ |
If the walls were thin enough it could, especially when used with higher pressures. Obviously R&D would need to be done, but steel can indeed stretch. |