Velocity to make a pistol HP effectively expand?
I know there are many factors that influence the effectiveness of a HP bullet and its ability to expand. But a friend and myself got into a discussion about the subject above. It is my understanding, just looking at velocity that the bullet needs to be moving 1000fps or better to properly work. Below 900fps forget it, it will not expand. 900fps to 1000fps maybe yes maybe no. My friend has his estimates 200 fps high than me. Thoughts?
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Pulled a little insert from XTP bullets I bought severalyears back. It list optimum velocities for the differnt bullets. Varies by caliber and bullet but some start as low as 700fps with the majority having 750-850 at the low end of the range. 0 -
Expansion is influenced by many other factors beside velocity. The construction/frangibility of the bullet. And what the bullet has to pass through before actually impacting it's intended target.
The FBI and other law enforce organizations have done a lot of studies and testing regarding this. Also there is a lot of interesting stuff available on U Tube.
My take on it is if you don't know how and what the bullet is made of, and what barriers it has to pass through before hitting it's target. No determination of expansion can be made one way or the other.
The U Tube videos I mentioned previously, are very enlightening regarding various commercial HP bullets. Some expensive ones produced by big name manufacturers expanded only minimally, fired at high velocity, (well over 1000 FPS), through 4 layers of denim into ballistic gelatin.0 -
The factors involved in ensuring expansion of a pistol hollow-point go well beyond velocity. The manufacturers of the bullets factor in the most likely use of the bullet in its design. A .451 230 grain HP will most likely be used in .45 ACP and they don't make your 1000fps threshold, but several of them expand very reliably in the 800-900 fps muzzle velocity range. My department used 230 grain Hydra-shok for service for years and had several shootings with it. All recovered slugs had expanded very uniformly and these chrono'd in the 825-850 fps area. Bullet core alloy or pure lead, jacket alloy and thickness, and nose skiving are some of the factors that will influence the expansion. 0 -
I loaded some 185 Golden Saber Rem full tilt in a 45 ACP and was not impressed. Most of the recovered bullets from regular hillside dirt looked like they could be cleand and reused. My swagged pure lead round nose ones with half jackets look like funny quarters went shot into 55 gal bbls. They don't penetrate but make a very deep dent.
If you want to end with large caliber bullets, it's easier to start with large caliber ones.
added "I never thought I'd have to shoot through dirt" Burt Gummer
Dirt seems to open the hollow points on my other stuff just fine. Might not be ballistic gelatin or flesh and blood but it's very handy.0 -
quote:Originally posted by 5mmgunguy
I know there are many factors that influence the effectiveness of a HP bullet and its ability to expand. But a friend and myself got into a discussion about the subject above. It is my understanding, just looking at velocity that the bullet needs to be moving 1000fps or better to properly work. Below 900fps forget it, it will not expand. 900fps to 1000fps maybe yes maybe no. My friend has his estimates 200 fps high than me. Thoughts?
Expansion is a function of velocity, bullet design, and what material the bullet is passing through.
Its simply not true as a blanket statement that bullets travelling below 900fps won't expand. If a bullet is designed to expand at 800fps, it can, and there are a few bullets like that out there.
Yes, most types of bullets won't expand reliably going that slow, but that's because they were designed to work at higher velocities. The problem is if you take a bullet designed to expand at a low velocity and run it at a high velocity, it can open up too quickly, losing penetration or even mass.
So its more about matching the bullet design to the caliber and velocity of the intended use.
Not incidentally, I'm not really convinced that bullet expansion is all its cracked up to be anyway. Its more about penetration and placement than expansion. If you want a fat bullet, start with a .45.0 -
Best way I've found to reliably tell if a certain make/weight of bullet is going to upset/expand is to test it with a piece of railroad track and a 28oz.Estwing framing hammer.
Place the bullet right side up on the track, raise hammer about a foot, then let it fall, controlling its' movement with your other hand.
If a 28oz. hammer makes it squish after falling a foot; you have an expanding bullet for velocities lower than 1000fps.0 -
quote:Originally posted by gunnut505
Best way I've found to reliably tell if a certain make/weight of bullet is going to upset/expand is to test it with a piece of railroad track and a 28oz.Estwing framing hammer.
Place the bullet right side up on the track, raise hammer about a foot, then let it fall, controlling its' movement with your other hand.
If a 28oz. hammer makes it squish after falling a foot; you have an expanding bullet for velocities lower than 1000fps.
Maybe this works in evaluating whether or a not a bullet will expand. . .but I don't think crushing a bullet between two steel objects is the best simulation of expansion in usually-softer human tissue.
The problem is that short of shooting bullets into human cadavers (which, as you can imagine, is a bit problematic), there is no perfect way to prospectively evaluate/model the expansion characteristics of bullets fired into human bodies. That's at least in part because human tissue isn't one consistency (you have skin, fat, muscle, bone, etc).
Typically, to test expansion of a given round, you fire it from an actual gun into ballistic test media.
The pros who do the most definitive testing typically use 10% gelatin media to simulate flesh, but you could use clay, soaked newsprint or telephone books, water jugs, or even a ham to give the same sort of ballpark simulation.
Here is the results (with pictures) of a whole bunch of different .38 special ammo fired into water jugs to give some sense of penetration and expansion:
http://www.snubnose.info/docs/snubby_ballistics.htm
Without getting into exact comparisons, it seems plain to me that of the rounds designed to do so, they actually are all expanding at under 900fps, some even fairly dramatically.
IMO, you may well be better off with a NON expanding 125 grain round at 1100 fps than a reliably expanding one at 850fps, but that's a whole different argument.0 -
quote:Originally posted by charliemeyer007
I loaded some 185 Golden Saber Rem full tilt in a 45 ACP and was not impressed. Most of the recovered bullets from regular hillside dirt looked like they could be cleand and reused. My swagged pure lead round nose ones with half jackets look like funny quarters went shot into 55 gal bbls. They don't penetrate but make a very deep dent.
If you want to end with large caliber bullets, it's easier to start with large caliber ones.
Hollow Points do not expand in dirt. They just clog up and act like FMJ, so your test does not mean anything as to real world effectiveness.0
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