The barrel will also effect velocity.
right or wrong(?) please tell me
the only thing that will determine the ''stopping power'' or ''punch'' or ''projectile velocity'' when talking about a weapon is the ammunition that is fired from it. basically it doesnt matter what kind of gun you fire a certain type of bullet out of that bullet is going to travel the same speed out of the gun and cause the same amount of damage to a target. other than possibly higher accuracy from being fired out of a longer barrel. so.. if you want more ''stopping power'' or want your bullets to travel faster you need to either change the size of the bullet or change the gunpowder grain count in the cartridge.
also speaking of grain count. what is the difference going to be with either firing 9mm with 115g as opposed to firing 9mm with 180g is there some kind of noticable difference? like more muzzle flash?? or a slightly different sound? more kick?
For instance, a bullet fired from an 18 inch barrel will have greater velocity then the same bullet/round fired from a 3" barrel. Also, things like twist rate, and the kind of rifling will effect accuracy and velocity. Barrels with polygonal rifling, such as GLOCK and H&K pistols, will, supposedly, increase velocity over standard barrels of the same length.
I'm by no means an expert, but I believe you should use lighter bullets in shorter barrels, as the heavier bullets do not attain high velocity out of a short barrel, I'm mainly talking about small pistols here, under 4".
First off what are you trying to evaluate? The "Great Caliber Debate" still rages on and within there are some that say that bigger is better while the opposing opinion says that shot placement trumps caliber. Regardless of which side of this particular facet of ballistic performance you reside on, the question you are trying to ask appears to be how to get more effect out out a firearm.
Not really a simple question as there are many facets and variables in this particular universe. First off "stopping power" is generally a neophyte reference to something that really only applies to long guns (rifles and shotguns) and generally not handguns. "Projectile performance" is a whole can of worms with many specific facets and to just ask about this subject in such a generalized manner will likely not get you the answer(s) you may be looking for.
When asking questions it is best to be a bit more specific and incluse some reference for context. By "punch" what are you trying to find out about? This would generate different answers depending on the application of a given firearm for a specific purpose. Target shooting (punching holes in paper), hunting (yes it can be done with a handgun and does), competition shooting, SD/HD (Self Defense/Home Defense) or other intended applications would be a good thing for potential responders to have an idea about rather than having to guess.
Specifically available in 9mm are bullet weights from 90gr to 147gr (gr = grain = 1 grain = 0.06479891 gram = 0.0022857142857 ounce). The basic principles of ballistics specifically involved in the detonation of a chambered round is another multi-faceted equation. The bullet weight being only one variable in this equation. The type and amount of powder used are a couple of others. Barrel length and type of rifling are a couple more. Beyond the basics one can get more complex by adding in: humidity, atmospheric/barometric pressure, air temperature and so on.
I realize I've written a lot here and probably not answered anything. Specific questions will get specific answers. You will get better answers and suggestions/recomendations by adding some form of context. I'm afraid there really isn't much to go on in your initial thread post. Do you have a firearm? What make and model? What caliber? What do you use it for? What are you trying to figure out or accomplish in the process of getting answers you are seeking?
alaskan viking pretty much answered my question just fine.
You should know, though, that you can't just buy a reloading kit and put in more powder to get more velocity. You might just increase instantaneous chamber pressure to a point where it damages the gun and doesn't really shoot any more. There's a correct blend of powder, gun and bullet that optimizes the complete firing solution. If you get it wrong, you can hurt yourself and/or break the gun. With factory ammunition rated "+P" or less you will probably be fine with any modern pistol. I'll leave reloading advice to the experts -- I'm not.
When evaluating possible loads for my weapons, I use the estimated muzzle energy as a guide line. This is ONLY for comparison purposes. It sounds complicated at first, but I have the formula memorized.
Muzzle Energy equals projectile weight (in grains) times Muzzle Velocity squared, divided by the constant of 450400....... Huh????
O.K. My Taurus is rated for a 124 grain bullet going at 1225 feet per second. That's 124 x 1225 x 1225 =186,077,500 / 450400 = 413.xxxx ftlbs muzzle energy. (Mass x M.V. x M.V.) / 450400 = M.E.
So, when looking for P.D. loads for it, I don't exceed 413 ftlbs., but I look for something close to the maximum.
At the Midway site, they have the ratings for most of the loads that they sell. This saves a lot of math time.
Now you just have to try them to determine which loads shoot close to Point Of Aim in you particular weapon. That's the fun part.
+1 to what Viking said. The only things I would add are that:
1. The only thing that will ever determine stopping power (IMO) is your target. If it stops, whatever you fired had enough stopping power.
2. 180gr 9mm - SWEET BABY JESUS! That would be like firing a brick from a BB gun.
A friend of mine who I don't get to see or talk to very often is looking at buying a handgun..He had told me before that he was looking at maybe a Glock..I saw him the other day (at a highschool basketball game) and I asked him if he ever bought one..he said no, that he had been looking and was thinking about a .40 becuz he said "you know...a 9mm would just go through someone, so I was thinking about a .40"...I have heard people say this about 9mm (even ayoob talked about it in a book he wrote a long time ago)...I didn't have time to go into much discussion with this guy about handguns at the time, but I am in the process of typing up some stuff for him and also a reference to coming to this site and asking people who know far more than I ever will about handguns..
I know with the ammo available today that 9mm does not always over penetrate..in the stuff I am typing up for him I am going into some things he needs to think about..Stuff like ammo cost, shooting often to make sure you can hit what you need to regardless of caliber...and if he is actually going to carry on his person, and that some of the bigger, full size guns are heavier and harder to conceal, etc..
anyway, what brought me to post on this thread is the velocity issue and if you carry 9mm which way would be best if you were carrying JHP in 9mm and you did not want to over penetrate..
I carry a 9mm and have for many years. The best way to avoid over penetration is to hit the sternum. That isn't always an option under duress. However, since Mr. Ayoob's earlier writings, there have been significant improvements in JHP designs and factory loads. Many of the current production 9mm JHP factory ammo will do just fine with minimal risk of over penetration. A .40 or .45 will just as easily over penetrate if ones shot goes through the arm rather than a thicker/more dense portion of an attacker. Shot placement trupms caliber, IMO, in the great caliber debate.
I've shot .40 from many makes and models of handguns and frankly it hasn't impressed me much. I'm sure it works just fine for those that like it. For it's lack of "wow" factor for me, coupled with the price of it over 9mm, I'll stick with what I am most proficient with and what is more easily affordable.
What do you recommend as a defensive round for my XD9 4" barrel? I know that when ayoob wrote that book it was in the 80's...I see from that ballistics test results what a big velocity difference there is from the weight of the bullet..I shoot my 9 very well with 115 grain practice ammo. I need to go back and look at what JHP I have in the mag now..My HD gun at the moment is my XD45 and it is loaded with 230 grain JHP..My main carry right now is my Smith 642 and again I would have to check, but it also has JHP in it...I am not sure the weight...I need to do some homework and look closer...The 642 has .38 spl +p in it...
"Stopping power" = NINE 00-Buck pellets, each 9mm in diameter, at about 1000 fps, striking a person AT THE SAME TIME! Preferably followed closely by nine more...
No pistol caliber round provides enough punch to "stop a man" in his tracks... No matter what the bullet weight, velocity, or caliber of a pistol bullet, only a spinal or cranial hit will ensure "stopping power"... The rest are just wounds that will hopefully deter the assailant from continuing to fight.
Stopping a fight is one thing. "Stopping" a person is another...
part of the reason i was asking this question was to determine what the purpose is in buying some handgun for $1200 as opposed to $350 in the case of this Kimber 1911 i shot as opposed to the Taurus pt-111 that i've fired 1500 rouds out of with no problems. im just wondering what exactly im paying for. seeing that all 9mm handguns in fact fire 9mm bullets some maybe able to pull the trigger and fire faster or maybe shoot a bit more accurately than others its just seems theres too big a price range for something that uses the same type of ammunition.
Now you're getting into ergonomics, manufacturing, and tolerances. There are distinct differences between different BRANDS of 9mm, but the effectiveness of the rounds out of a 3" vs a 4" are not very big, all things considered.
Different pistols have different grip angles, therefore they are more comfortable to one person than another pistol may be. Lending itself to being able to shoot it better than some other pistol.
Different pistols have different bore axis' perhaps lending themselves to faster follow up shots (if it's a lower bore axis)
Different pistols are manufactured to higher or (sadly) lower standards than others, paying more does (most of the time) get you a pistol that is built to better standards. There are exceptions to this though.
Different pistols are built to better tolerances, which lends to their reliability, repeatability, fit, form and function. Guns can be manufactured really well, but have a poor set of tolerances. For instance, if a slide isn't fitted well with the slide, it can be out of the best steel, coolest design, but it won't work right. Keep in mind that tight tolerances aren't always the best for all platforms.
Does that help define what you are looking for? Ask more questions... we'll figure it out. hehehe
you need to search on "hatcher formula"
in his equations he also gives some credit to the type of bullet design
i have several spreadsheets and items on his formula and results of stopping power
his formula gives heavy weight to the diameter of the bullet - thus the start of the 9mm vs 45 arguments
Ok, maybe you cannot tell that there is a difference. Well, oddly enough there is, and a particular commodity such as firearms are no different from many other consumer product categories.
IOW, as zhurdan from the planet Zardoz alluded to - you get what you pay for, and caliber has no bearing on this....