Tumbling VS Keyholing question

[mikemaccham]

So I was looking at ordering a AK-74 for $350, and some of the online reviews complained about keyholing due to a new american barrel that is a bit to large (I think its the centerfire bulgarian ak74).
Don't 5.56 and 5.45 tumble due to a hollow core? I thought that was one reason why they were considered pretty bad rounds to get hit with due to the tumble(not many I would want to get hit with). I also thought these rounds were extremly accurate.
So does keyholing lose accuracy? Could I still hit a chest at 500 yards? It would kind of seem like a good thing if I could stay on target...

[11Z50]

Urban legend.

[mikemaccham]

Urban legend.

The part about losing accuracy?

[Fjold]

It depends on whether you are talking about tumbling in flight or tumbling in the body after it hits. Just because a bullet has a hollow cavity doesn't mean it's going to tumble in either case. The 5.56 Nato bullets don't have a hollow cavity.

[mikemaccham]

Ya, I was just wondering if keyholing loses accuracy at long distances (I dont care about sub MOA, just if could you still hit a guys chest at 500 yards) with a cheap "keyholing" ak74 w/ 5.45,
and if tumbling and keyholing are the same thing.

[Beelzy]

Tumbling is the name for the flight of an un-stabilized bullet, Keyholing is the result of said bullet when it contacts the target.

The urban myth about .223 and tumbling came about when super light bullets were being
shot out of barrels with to slow a twist. These bullets would not stabilize correctly and would keyhole the targets.

[Scratch705]

i thought tumbling was what happens to a bullet after it enters the body thus creating a bigger wound cavity, while keyholing is when the bullet while mid-flight is tumbling end over end before hitting the target.

tumbling is good for killing, keyholing is bad for accuracy

[Jpach]

i thought tumbling was what happens to a bullet after it enters the body thus creating a bigger wound cavity, while keyholing is when the bullet while mid-flight is tumbling end over end before hitting the target.

tumbling is good for killing, keyholing is bad for accuracy

This!

[mikemaccham]

I think I have heard it both ways thats why I asked.
so bullets spinning through air can still be very accurate
spinning bullets = bad for bad guys
cheap AK is hit or miss on being accurate...

[mzimmers]

We seem to have some differing opinions on terminology here. To me, keyholing is a term to describe the shape that an unstabilized bullet makes when it hits a paper target. Tumbling describes what happens after the bullet enters the body of a living target. The point is that a bullet that *tumbles* can still have been perfectly stabilized in the air.

If I remember correctly (hah!) the USGI 5.56 rounds were notorious for tumbling, but this wasn't by design; it was just a fringe benefit that was discovered later. The 5.7x28, on the other hand, was designed especially for tumbling properties.

So, if your goal is maximizing tissue damage, tumbling is a good thing. But, the lack of in-flight stability that creates keyholing is never a good thing. To answer the OP's question, no way in hell would I trust a keyhoilng bullet to hit something the size of a human chest at 500 yards, or even 100 yards.

I have an old Ruger 44 carbine. Neat gun, but very slow barrel twist that keeps me from using bullets over 270 grains. When I tried Barnes Busters (300 grains), I was all over the place at 50 yards. At 100 yards, I doubt I could have hit the paper more than half the time.

[mikemaccham]

Thank you M.

[joelogic]

Paper would not cause a bullet to tumble. If there is a keyhole on your paper target something is wrong with your gun. My gun started to keyhole after about an 800 round weekend, cleaned the barrel, went back to being a straight shooter. It would keyhole at 50yds and at 200 I couldnt hit a man size target. So no, you couldnt hit a man at 500+ yards with a keyholing bullet.

[J-cat]

It could be that the barrel uses the wrong twist rate and understabilizes the bullet. That bullet will tumble in flight and print keyholes on paper.

All spitzer type bullets will tumble in flesh, depending on their mass. The lighter the bullet, the sooner it will tumble. The reason is the base of these bullets is heavier than the nose and the most desirable shape for traveling through liquid is a teardrop. The bullet will want to adjust itself after impact hence the tumbling.