Copper Bullets?

[wally]

I read the original URL article. Under 12" (10-7/8") penetration in a 5" barreled 1911 tells me to forget about it in a sub-compact. YMMV.

--wally.

 

[CPshooter]

I read the original URL article. Under 12" (10-7/8") penetration in a 5" barreled 1911 tells me to forget about it in a sub-compact. YMMV.

--wally.

Isn't there the possibility of MORE penetration in a shorter barrel? A 5" barrel would definitely allow the bullet to leave at a faster speed, but at faster speeds a hollow-point bullet tends to expand faster and more instantly upon impact. This usually leads to underpenetration. Of course, there's always the possibility that if it was going too SLOW, it wouldn't expand at all or not enough and overpenetrate.

I think every application is different and it's hard to predict exactly how a certain round will perform in any given situation.

From what I've read, I was under the impression that the all copper Barnes bullet tends to penetrate deeper than a regular JHP, assuming both were the same weight and traveling the same speed. They also retain 100% of their weight after impact, even through hard barriers like car doors and such. Don't know how accurate those claims are though...

The copper bullets seem ideal for short-barrel handgun applications and also hunting for the reasons already mentioned.

 

[RyanM]

Isn't there the possibility of MORE penetration in a shorter barrel? A 5" barrel would definitely allow the bullet to leave at a faster speed, but at faster speeds a hollow-point bullet tends to expand faster and more instantly upon impact. This usually leads to underpenetration. Of course, there's always the possibility that if it was going too SLOW, it wouldn't expand at all or not enough and overpenetrate.

Actually, you're precisely right for the majority of bullets. Slower velocity = less expansion = deeper penetration. Even so, I'd want to see the stuff thoroughly tested out of the barrel length I'd plan on using it in, especially through heavy clothing. Less velocity usually, though not always, means less reliable expansion after hitting clothing.

On copper vs. lead and copper, Barnes rifle copper bullets are indeed good penetrators, but only because they retain full weight, while good quality non-bonded JSPs are usually in the 50% to 70% retained weight range, and even bonded ones can commonly be 60% to 80% or so. Very few bonded JSPs consistently retain 100% of their weight.

Handgun bullets, on the other hand, almost always retain over 90% of their weight, unless they're prefragmented or driven to over 1200 fps. So there's going to be very little difference.

 

[McCall911]

If Sir Isaac Newton was right, penetration is a function of bullet length and bullet density:
http://en.wikipedia.org/wiki/Impact_depth
(Seeing that Sir Isaac was such a Mr. Smartypants, he probably was right.)

So this may just be a case of not enough bullet length.

I suppose I didn't give the whole explanation...

Copper bullets, being of a lower density than lead-containing bullets, are necessarily longer.
So if Sir Isaac was right, then a copper bullet might (in theory) penetrate deeper than the corresponding lead-containing bullet.

But in this case, by George, the copper bullet didn't penetrate too well at all, so its extra length didn't help. (If Newton's estimation is valid in this case.)

 

[Big Boomer]

You are also forgetting about one MAJOR aspect of the bullet design, when the bullet expands it does so in a petal formation, NOT a mushroom.

The point being that this * vs o is that the surface area of the expanding bullet will be greater and have more resistance in a standard hp bullet, as the copper construction with the petals allows impact matter to flow in between the petals lowering the resistance because it has less surface area therefore penetrating deeper.

Imagine a parachute opening as you fall from an airplane now take 40% of that parachute and cut slats into it, your resistance, or drag from the chute will be much less and you will fall much faster by allowing more air to pass through.

Same principal in the bullet design just different materials. I believe they both expand to about the same size.

 

[Harley Quinn]

But in this case, by George, the copper bullet didn't penetrate too well at all, so its extra length didn't help. (If Newton's estimation is valid in this case.)

I would have to say the violent wound channel and its opening on contact is the reason for a lack of further penetration. It is a lot more complicated now that the designs are so much more complicated than the simple theory you are pointing out

This bullet did its job missed the 12" mark laid down by someone, take a hard cast bullet and you will get better penetration but not as violent a wound channel. Looks like to me they have made a very good bullet and the fps is the criteria. This bullet for man is very good. I tried to buy some of these from a dealer in OK, but they were all sold out "Taurus". So I went to a store, local and they were sold out also, they say there will not be anymore coming into the country. Hmmm

Take that bullet with a flat nose similar to a wadcutter/semi wadcutter, and you are going to get a lot of penetration and less expansion (the original thought "Newton")

That same bullet in a 10mm would be interesting to see its penetration and wound channel (same weight)