Let's discuss Bullet Penetration
02-05-2008, 03:41 PM
#31
Senior Member
Join Date: Jan 2004
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Posts: 1,813
RE: Let's discuss Bullet Penetration
ORIGINAL: eldeguello
Well, before I look at your results, I will guess it was either the .220 Swift or the .22/250. This guess is based on the results of similar tests run by people like Phil Sharpe, Townsend Whelen, and Harvey Donaldsonwhen they were developing .22-cal. varmint rifles back in the 1930's..... The HV .22 bullets, regardless of type, would often blow hens-egg sized holes through steel plate that even a .30/'06 AP round only made a smear on....
Well, before I look at your results, I will guess it was either the .220 Swift or the .22/250. This guess is based on the results of similar tests run by people like Phil Sharpe, Townsend Whelen, and Harvey Donaldsonwhen they were developing .22-cal. varmint rifles back in the 1930's..... The HV .22 bullets, regardless of type, would often blow hens-egg sized holes through steel plate that even a .30/'06 AP round only made a smear on....
When it came to bigger calibers, the ones that did the most damage (even in T1 steel) were the higher velocity rounds with NP's loaded in them!
DM
02-05-2008, 08:01 PM
#32
Nontypical Buck
Join Date: Nov 2006
Location: Where the ducks don't come no more
Posts: 4,420
RE: Let's discuss Bullet Penetration
The only thing I can figure is that friction has something to do with it. That fast bullet must hit with such force that melts of softens the steel much as a shaped charge would do.
That... or perhaps its just like trying to throw a pencil through a sheet of notebook paper... have someone hold just the top, and the pencil will fall to the floor... the paper gives way... have someone hold the top and the bottom... pencil will go through even sideways.... the tighter you pull the paper... the easier it is for the pencil to make it through.
So it may be with steel and fast bullets.... steel has a great resistance, but when it comes to a certain point with speedy bullets, the tougher the target and the more the resistance... the better they work.
But looking at it as such... its a great varmint round, but don't expect it to work that way on bigger game... whitetail size and up.
That... or perhaps its just like trying to throw a pencil through a sheet of notebook paper... have someone hold just the top, and the pencil will fall to the floor... the paper gives way... have someone hold the top and the bottom... pencil will go through even sideways.... the tighter you pull the paper... the easier it is for the pencil to make it through.
So it may be with steel and fast bullets.... steel has a great resistance, but when it comes to a certain point with speedy bullets, the tougher the target and the more the resistance... the better they work.
But looking at it as such... its a great varmint round, but don't expect it to work that way on bigger game... whitetail size and up.
02-06-2008, 04:23 AM
#35
Nontypical Buck
Join Date: Dec 2004
Location:
Posts: 1,839
RE: Let's discuss Bullet Penetration
Two things factor into this equation .....
Sectional density of the bullet and velocity..Not bullet weight and velocity..
Smaller cal bullets of the same weight and construction have a higher sectional density than the bigger calbullets .Ultimately, bullets,with highersectional denisty,will hold together better, and penatrate deeper....
But of course for every action there is an equal and opposite reaction...For the 220 swifts, light bullets(small Sectional denisty) bullets are well known tobreak apartin mid flight when you push them too fast..
You can try and make a 50 gr. 30cal bullet or .270
bullet, but we all know whats gonna happen, in order for these two bullets to weigh 50gr, the wall jacket will be so thin (with probably no lead ion the middleresulting invertually no sectional denisty) will desintigrate as soon as you pull the trigger...
And if ya tried to fire a 130 or 150 gr 165gr.(very, very high sectional denisty). .22cal bullet out of a .22 cal firearm, your gun would probably blow up due to excesive pressure.....
So ya, having a high sectional density and high velocity, I could see it going through..
But I could also see anycaliber gun,withthe same velocity as a .220 Swift(you'll need an Ultra mag) shooting the same sectional denisty bullet as the one that was used on the .220 swift, going through that 3/4 steel....
But it nice not to have that recoil
Good Job......
Sectional density of the bullet and velocity..Not bullet weight and velocity..
Smaller cal bullets of the same weight and construction have a higher sectional density than the bigger calbullets .Ultimately, bullets,with highersectional denisty,will hold together better, and penatrate deeper....
But of course for every action there is an equal and opposite reaction...For the 220 swifts, light bullets(small Sectional denisty) bullets are well known tobreak apartin mid flight when you push them too fast..
You can try and make a 50 gr. 30cal bullet or .270
bullet, but we all know whats gonna happen, in order for these two bullets to weigh 50gr, the wall jacket will be so thin (with probably no lead ion the middleresulting invertually no sectional denisty) will desintigrate as soon as you pull the trigger...
And if ya tried to fire a 130 or 150 gr 165gr.(very, very high sectional denisty). .22cal bullet out of a .22 cal firearm, your gun would probably blow up due to excesive pressure.....
So ya, having a high sectional density and high velocity, I could see it going through..
But I could also see anycaliber gun,withthe same velocity as a .220 Swift(you'll need an Ultra mag) shooting the same sectional denisty bullet as the one that was used on the .220 swift, going through that 3/4 steel....
But it nice not to have that recoil
Good Job......
02-06-2008, 07:39 AM
#36
Join Date: Jan 2008
Location: Texas
Posts: 425
RE: Let's discuss Bullet Penetration
Jeff, I've shot several 1,000 rounds through a .220 Swift and a .22/250 and generally I was pushing them for all the velocity I could squeek out of them. I NEVER had a bullet blow up in flight. I think you've been reading gun magazine stories by people who don't know what they are talking about. On the other hand, I have seen such bullets blow up on impact with some obstruction in their flight. I've shot at long range varmints only to see my bullet clip a mesquite branch near the target and explode in a gray puff. But they don't just fly apart on their own that I've ever seen.
To talk about penetration, perhaps we should consider what out tanks and other tank killer guns shoot today. Tanks shoot the small sabot round of very dense, very small diameter projectile going very fast. It's basically a giant .220 Swift and the sabot goes thru enemy armor like it's hot butter. If that doesn't work they can change to the shaped "HEAT" charge which burns it's way inside the tank.
There's no mystery here. Small size and lots of speed applied to very small area is what drills steel. Where 30 caliber AP ammo will impress you is when it's shot into something like a tree or sand. You'll dig a hole a couple feet deep to find an AP shot into sand.[:-]
To talk about penetration, perhaps we should consider what out tanks and other tank killer guns shoot today. Tanks shoot the small sabot round of very dense, very small diameter projectile going very fast. It's basically a giant .220 Swift and the sabot goes thru enemy armor like it's hot butter. If that doesn't work they can change to the shaped "HEAT" charge which burns it's way inside the tank.
There's no mystery here. Small size and lots of speed applied to very small area is what drills steel. Where 30 caliber AP ammo will impress you is when it's shot into something like a tree or sand. You'll dig a hole a couple feet deep to find an AP shot into sand.[:-]
02-06-2008, 07:45 AM
#37
Giant Nontypical
Join Date: Feb 2003
Location: Texas - BUT NOW in Madison County, NY
Posts: 6,270
RE: Let's discuss Bullet Penetration
Light, Fast and Devastating By Russell Thornberry
"Battlin’ Bullets - The perennial campfire debate continues. Which hunting projectile is best? Light and fast, or heavy and slow?
P.O. Ackley, the godfather of American ballisticians, forgot more than most of us will ever know about bullet performance. Many years ago, I read his double volume “Handbook for Shooters & Reloaders.” When I turned to his chapter entitled “Killing Power” in Volume I, I fully expected a treatise on why .50-caliber bullets are more deadly than .49-caliber bullets. However, I was amazed to fine something different - something that Ackley called “shockdown power” rather than “knockdown power.”
His premise is simply that the more speed increases, the more shock increases. And when speed passes the threshold of 4,000 feet per second, a whole new dynamic is created - one that cannot be equaled with lesser speed, no matter how large the bullet.
His classic test, which proved his point, was conducted by shooting bullets into ½-inch-thick steel-armor plate from the frontal area of a U.S. military half-track. At a distance of 30 feet, he shot a .270 Win with 100-grain bullets, a .30-06 with military-issue, solid-steel, armor-piercing bullets, and a .220 Swift with a 48-grain bullet.
The results were astounding. The .270 bullet left a shiny spot on the armor plate and did not penetrate at all. Two shots from the .30-06 armor-piercing bullets left shallow craters .070 and .098 inch respectively.
The little .220 Swift bullets consistently burned 3/8-inch diameter holes completely through the ½-inch armor.
The results spoke for themselves. Crossing the threshold of hypervelocity created a dynamic as a result of shock that cannot be achieved any other way.
Ackley’s test was done on armor plate, but how does that translate to performance on the flesh and bone of wild animals? Ackley went on to say that if he had to pick only one rifle for hunting North American game, it would be a .220 Swift.
If, in Ackley’s day, he had had access to the slower-burning powders of today, he would have been able to propel even larger-diameter bullets at “hyperspeed” - bullets traveling 4,000 or more feet per second at the muzzle. I speculate that he would have chosen a larger-caliber, heavier bullet capable of hyperspeed for his choice North American game rifle."
The above brief quoteis exerpted from anarticle appearingin the October 2005 Buckmasters Gun Hunter,reprinted by Barnes Bullets with the author’s permission.
In addition to his penetration tests on steel plate, Ackley cited the results of the use of a .30/'06, a .220 Swift, and an 8X57mm Mauser on wild burros. The .220 Swift made more consistent 1-shot kills on these big, tough "varmints" than either of the larger-caliber rifles which used standard big-game hunting ammunition. (See P 79 of Ackley's handbook for Shooeters and Reloaders, V I. The burros averaged about 600 pounds-probably as tough as an average-sizebull elk.)
"Battlin’ Bullets - The perennial campfire debate continues. Which hunting projectile is best? Light and fast, or heavy and slow?
P.O. Ackley, the godfather of American ballisticians, forgot more than most of us will ever know about bullet performance. Many years ago, I read his double volume “Handbook for Shooters & Reloaders.” When I turned to his chapter entitled “Killing Power” in Volume I, I fully expected a treatise on why .50-caliber bullets are more deadly than .49-caliber bullets. However, I was amazed to fine something different - something that Ackley called “shockdown power” rather than “knockdown power.”
His premise is simply that the more speed increases, the more shock increases. And when speed passes the threshold of 4,000 feet per second, a whole new dynamic is created - one that cannot be equaled with lesser speed, no matter how large the bullet.
His classic test, which proved his point, was conducted by shooting bullets into ½-inch-thick steel-armor plate from the frontal area of a U.S. military half-track. At a distance of 30 feet, he shot a .270 Win with 100-grain bullets, a .30-06 with military-issue, solid-steel, armor-piercing bullets, and a .220 Swift with a 48-grain bullet.
The results were astounding. The .270 bullet left a shiny spot on the armor plate and did not penetrate at all. Two shots from the .30-06 armor-piercing bullets left shallow craters .070 and .098 inch respectively.
The little .220 Swift bullets consistently burned 3/8-inch diameter holes completely through the ½-inch armor.
The results spoke for themselves. Crossing the threshold of hypervelocity created a dynamic as a result of shock that cannot be achieved any other way.
Ackley’s test was done on armor plate, but how does that translate to performance on the flesh and bone of wild animals? Ackley went on to say that if he had to pick only one rifle for hunting North American game, it would be a .220 Swift.
If, in Ackley’s day, he had had access to the slower-burning powders of today, he would have been able to propel even larger-diameter bullets at “hyperspeed” - bullets traveling 4,000 or more feet per second at the muzzle. I speculate that he would have chosen a larger-caliber, heavier bullet capable of hyperspeed for his choice North American game rifle."
The above brief quoteis exerpted from anarticle appearingin the October 2005 Buckmasters Gun Hunter,reprinted by Barnes Bullets with the author’s permission.
In addition to his penetration tests on steel plate, Ackley cited the results of the use of a .30/'06, a .220 Swift, and an 8X57mm Mauser on wild burros. The .220 Swift made more consistent 1-shot kills on these big, tough "varmints" than either of the larger-caliber rifles which used standard big-game hunting ammunition. (See P 79 of Ackley's handbook for Shooeters and Reloaders, V I. The burros averaged about 600 pounds-probably as tough as an average-sizebull elk.)
02-06-2008, 08:06 AM
#38
Join Date: Jan 2008
Location: Texas
Posts: 425
RE: Let's discuss Bullet Penetration
I'm not so sure about this mythical 4,000 fps, although there is no one whose opinion I respect more on all things firearm related than P.O. Ackley. The fact is a fast moving .224 caliber bullet is wicked good at penetrating metal. A bullet going 3,500 fps, for example, won't do as good as one going 4,000 fps...but it WILL penetrate a hell of a lot. And so on down the line. As I say, I don't think there is any magic velocity and I've spent a lifetime trying to shoot holes in crazy things.
But before anyone gets the idea a very fast .224 bullet will shoot through anything, let me hasten to say it's not so. There is a big difference between setting up various types of steel plate and shooting it head on with different projectiles than what happens in the real world. A very fast .224 bullet is capable of tremendous penetration...but only once. After the bullet has penetrated the initial object, there is usually nothing left of it, i.e. it comes apart.
The best way to get some real world appreciation of what works and what doesn't may be to find an abandoned old car. These make wonderful "targets" for the curious. Here a hot .22 rifle is only fair at going completely through the car body side to side. Most times it will penetrate side A and blow up so there is little or nothing to penetrate side B. More conventional high powered rifles like .308 or 30/06 do better at the thru and thru penetrations but still hardly any guarantee. Frequently their bullets will hit something and get deflected. A .30 caliber bullet is about as likely to exit the roof of floor as the opposite side of the car. Tests have shown that about the only things that will reliably punch in one side and out the other are the 50BMG and believe it or not a 12 ga slug.
Keep in mind this is not a pure AP test but more of a "real world" test of what goes through what and how. A .220 swift may go through more plate steel but for general uses you'll be better off with a clip full of .308 AP for smoking people out of cars and houses and even woods.
This is a difficult subject to compare apples to apples.
But before anyone gets the idea a very fast .224 bullet will shoot through anything, let me hasten to say it's not so. There is a big difference between setting up various types of steel plate and shooting it head on with different projectiles than what happens in the real world. A very fast .224 bullet is capable of tremendous penetration...but only once. After the bullet has penetrated the initial object, there is usually nothing left of it, i.e. it comes apart.
The best way to get some real world appreciation of what works and what doesn't may be to find an abandoned old car. These make wonderful "targets" for the curious. Here a hot .22 rifle is only fair at going completely through the car body side to side. Most times it will penetrate side A and blow up so there is little or nothing to penetrate side B. More conventional high powered rifles like .308 or 30/06 do better at the thru and thru penetrations but still hardly any guarantee. Frequently their bullets will hit something and get deflected. A .30 caliber bullet is about as likely to exit the roof of floor as the opposite side of the car. Tests have shown that about the only things that will reliably punch in one side and out the other are the 50BMG and believe it or not a 12 ga slug.
Keep in mind this is not a pure AP test but more of a "real world" test of what goes through what and how. A .220 swift may go through more plate steel but for general uses you'll be better off with a clip full of .308 AP for smoking people out of cars and houses and even woods.
This is a difficult subject to compare apples to apples.
02-06-2008, 01:30 PM
#39
Join Date: May 2004
Location:
Posts: 429
RE: Let's discuss Bullet Penetration
I can believe this. Velocity being the key, not necessarily caliber. From my own experience on 1/2" steel at 300 meters using a 30-06 versus a .300 RUM with same bullet (Nosler BT) the '06 left little more than a bullet smear, the .300 RUM left a 3/4" hole. Really opened my eyes on what the effect of 500 fps increase in velocity can have.