Key Hole Targets Sign of Unsized Bullets?

[340six]

Well :coffeecom

[303Guy]

I've had key-holing from sized boolits, so I'd say no. Boolit design was the culprit in my case. That and over sizing the cases which in turn sized the boolits.

[docone31]

Bent barrel?

[Gohon]

Key Hole Targets Sign of Unsized Bullets?

Maybe, maybe not. Want to be a little more specific? Like caliber, bullet type and weight, bullet size, bore size, and barrel twist. There is no one shoe fits all but somewhere along the way the bullet is not stabilized.

[excavman]

Key-holing is a sign of instability. The boolit must be spinning along its base to nose axis to remain stable in flight, otherwise it will start to tumble and accuracy will be lost. The faster the rotation the more stable the projectile. This is a product of muzzle velocity and rifling twist. Too slow of a rifling twist rate for the length of the boolit will cause instability. Weight is not the only factor, a long hollow point boat-tail bullet will lose stability easier that a short round nose slug of the same weight. An undersized or too soft a slug may skip over the lands of the rifling and cause the same effect. Ways to avoid key-holing is higher muzzle velocity, faster twist rate, shorter boolit length, boolit sized to groove diameter or greater, harder alloy and use of jacketed (as a last resort) bullets. There may be other cause such as barrel leading or worn out rifling but they are all related to spin rate.

Larry

[MtGun44]

No.

Most likely cause is undersized boolit. This is extremely common with the 9mm Luger
with cast, esp on European pistols which often have large groove diam and very
shallow rifling.

On rifles, it can be too long a boolit for the rifling twist.

[HeavyMetal]

"Key holing" can be caused by many things some in the boolit and some in the gun.

The obvious malfunction is a bad crown on the end of the muzzle. Any imperfections here can cause all kinds of trouble.

After checking that the next step is to take a good hard look at what you are shooting and what you are shooting it in!

To that end we will need more information: alloy, mold type and brand, weight, powder charge, type of lube.

With these we can make all kinds of guess's.

[snuffy]

Well :coffeecom

Well l-lell! Just drop an open ended question, sit back and watch????¿¿¿

Like others have said, MORE INFO REQUIRED!

[smlekid]

I had tumbling issues in my 9mm sizing boolits to 357 in a 356 barrel in my case it turned out to be to soft an alloy as I melted down the remaining boolits added some lino and the problem went away

[mooman76]

No!!!

[340six]

Well l-lell! Just drop an open ended question, sit back and watch????¿¿¿

Like others have said, MORE INFO REQUIRED!
Sorry I was running all the 380,9mm and 45acp brass to resize,bell the cases shot thursday night with a single stage press.
And prime{with the rcbs hand primer tool} Like 1000 rnds all thogether
It was the 45acp shot in the SA Bisley Black Hawk sized to 451 shot a small amount as a test and looked to be key holed but may have been bullet style.
Thus me asking.

[chris in va]

Funny thing, an old RO at the range I visit noted my 9mm was keyholing and said it's actually a good thing for home defense purposes. Bigger wound channel and all that.

[armyrat1970]

Funny thing, an old RO at the range I visit noted my 9mm was keyholing and said it's actually a good thing for home defense purposes. Bigger wound channel and all that.

Well don't know about that? I guess of course it depends on where you place the shot in the first place?
Keyholing can be a sign of, I think, four different problems.
1. Dirty bore.
2. Sloppy boolit fit to bore.
3. Crown worn out.
The fourth one is the wrong boolit weight for the weapons barrel twist.
(not often happening with handguns at very close ranges, though will become apparent at longer ranges)

If you are casting boolits and using them unsized, and they are keyholing, you may have either one of these problems.

[Bret4207]

Funny thing, an old RO at the range I visit noted my 9mm was keyholing and said it's actually a good thing for home defense purposes. Bigger wound channel and all that.

Yeah, sure, unless the tumbling causes he boolit to not penetrate in which case you'll just create a mad BG.