Bullets tumbling in game?

I'm not much of a hunter so, following the reading of a local magazine, I've got to ask: do expanding bullets tumble and "won't pass through an animal nose first", because of asymmetrical expansion?

thnks

That article sounds like a good candidate for the Golden Manure Fork Award. I suspect either a serious case of cabin fever with accompanying delusions, or a rectal cranial inversion. :) Could it be that someone with tongue firmly planted in cheek was having some fun with a gullible writer who took it seriously?

It is no more normal in a good hunting load than it would be in a target load.

As to tumbling, two things commonly cause bullets to destabilize in flight: defects in the bullet's base, and crown damage to the rifle. There are other causes, but those are the two most often responsible. Wrong twist rate, wrong powder or wrong charge, weak alloy for velocity are some others, and there are probably more I don't remember off the top of my head. None of them are in any way conducive to accuracy - the load patterns like a shotgun instead of grouping. If it's happing in a hunting load, there's a real problem beyond the obvious one of inaccuracy - the inability to insure a quick and humane kill.

Some bullets will tumble once inside the animal, especially if they hit a large bone with a glancing blow, but that is not the same thing as tumbling in flight. Maybe that is what was meant by "won't pass through an animal nose first", with the emphasis on "pass through". IME, bullets that exit large game usually leave a nice round exit hole (bigger than the entrance wound) from uniform expansion.

Expansion should not begin until after the bullet has entered the animal, and "asymmetrical expansion", though it is a term I have not encountered before, could be caused by a defective bullet or a bone strike. One exception to note: Firing a bullet designed for relatively low velocity (e.g. .22Hornet) out of a high vel cartridge (e.g. .22-250) will sometime result in the bullet self destructing in flight.

HP's can make a mess, but they are usually used for small, medium, and two-legged varmints, and they do it by uniform (symmetrical) expansion and dropping fragments on the way, unless they hit something hard. They won't expand if they are tumbling as they rely on hydraulic pressure to open up.

The thing is copyrighted, but goes along the lines of:
Few hunters realise that bullets begin to tumble at the impact rather than moving nose first;
it is easy to see in ballistic gel;
if you think about it, the reason is that they cannot expand perfectly, one side will drag more than the other;
so that's why some hunters find bullets backwards in their game.

I would think that a bullet would skid on its side and have a curved path if that happened; but again, that's just thinking.
I saw some data on the old 5.56 NATO somewhere on the web and will try to find it again; maybe it includes some ballistic media tests.
kg

There have been mil bullets that were specifically designed to tumble upon entry. I remember reading about them, but didn't retain any details. (Parts are no longer available for my rememberer.)

Just speculation on my part, but I would think that the longer the bullet is in relation to its diameter, the more stable it would remain upon entry, assuming it didn't strike something hard. Living animals are not consistent in density like ballistic gelatin is, and hide, bones, muscle, fat, lungs, etc. all affect the bullet differently as it travels through the body. Quartering shots especially do not always travel in a straight line, but for the most part, IME they expand properly, which would not be the case if they were tumbling. I would believe that it could happen if there were fragmenting: shedding pieces of jacket and core. That happens often enough to be notable, especially with lighter, faster bullets, and with HP's as they open and shed "petals" along the wound channel.

I think the situation the writer was trying to describe has more to do with poor bullet choice for the shot attempted that it does common occurrence. Most large game hunters (bear & moose) that I know personally prefer to use heavier for caliber bullets with larger bore rifles. OTOH, deer hunters here use a dizzying array of different cartridges and may well be more likely to see strange things happen. For instance, we have dropped deer with 117gr cast soupcans out of .30-30's with clean broadside shots, but I would never even consider firing a bullet that light for caliber at a quartering angle. I would expect a short light bullet like that to behave strangely once it began to lose momentum to friction in the passage through different densities of tissue. I would count on a heavier bullet to travel straighter and penetrate much better. A tumbling bullet would not penetrate as well, though the resulting wound channel might be bigger and as it did not exit would transfer 100% of its energy to the animal. This might or might not result in a quicker kill. That said though, every animal is different, and every shot behaves differently, even when the circumstances are as alike as concievable.

He may have a point, maybe even a valid one, but I still think he's been smoking something funny..... :animal26: The deer in the freezer are certainly not venturing any opinions.

Spitzers were designed to tumble. They came about as a way around the Hague Convention's ban of expanding ammo. The spitzer is heavier at the rear than the nose so it is more likely to "YAW" then tumble through.
Look up "DumDum" and "7.92x57mmIS" if you want to know more.