Keyholing - Ammo? or Gun ??

micallen · 12-05-2007, 07:21 AM

Are certain types of ammo more prone to keyholing, or is that a gun issue?? I'm speaking specifically about a .45 ACP.

billy · 12-05-2007, 07:30 AM

i would say the gun.

nathangdad · 12-05-2007, 08:02 AM

The round is relatively slow moving and will keyhole at a certain distance. This is normal and many people welcome this as a performance enhancer as the bullet will stay in the target thus transmitting all hydrostatic shock energy to the target. Actually, any .45 acp round design will eventually keyhole.

micallen · 12-05-2007, 09:16 AM

Quote:

Originally Posted by nathangdad

The round is relatively slow moving and will keyhole at a certain distance. This is normal and many people welcome this as a performance enhancer as the bullet will stay in the target thus transmitting all hydrostatic shock energy to the target. Actually, any .45 acp round design will eventually keyhole.

It was 230 GRAIN FMJ. I was only shooting from 30 feet though.

just_a_car · 12-05-2007, 10:48 AM

Quote:

Originally Posted by billy

i would say the gun.

At 30 feet?... I agree. Take it to a smith to see if the crown or barrel is messed-up.

lefty o · 12-05-2007, 11:29 AM

keyholing is not normal, and is indicitive of a problem. 2 normal culprits are bullet weight that is unsuitable for the barrels twist rate, or the crown is damaged.

micallen · 12-06-2007, 10:00 AM

I may call Taurus today.

rondog · 12-06-2007, 02:19 PM

What were you shooting at? Some types of target paper will give you a hole that is torn, not punched cleanly. Maybe try a piece of cardboard and see if you get different results.

micallen · 12-06-2007, 02:53 PM

Quote:

Originally Posted by rondog

What were you shooting at? Some types of target paper will give you a hole that is torn, not punched cleanly. Maybe try a piece of cardboard and see if you get different results.

It was "printer paper" as I printed a target using Autocad. I had 2 corners stapled to a piece of 1/2" thick OSB board.

I called Taurus, and they told me to send it in, but before I spend $45 shipping, I am going to try a few more things. After all, I've only fired 9 rounds. I may polish the crown ligtly, and try better target paper. Also test difference in the 230 grain bullet and a lighter bullet.

I've read a lot on barrel crowns today. I will also try the "white-out test."

micallen · 12-07-2007, 02:57 PM

UPDATE:

I fired 15 rounds today (into a cardboard box). Actually, I fired 10, and the local expert marksman here fired the other 5.

Good news is: NO keyholing. I can assume it was becaus of the thin paper last time.

Bad news: 1st shot high, all other shots low. For me and the "expert." Same thing Monday when I shot it for the 1st time.

just_a_car · 12-07-2007, 05:59 PM

Quote:

Originally Posted by micallen

Bad news: 1st shot high, all other shots low. For me and the "expert." Same thing Monday when I shot it for the 1st time.

That sounds like a 'fouling shot' issue.

micallen · 12-07-2007, 10:36 PM

Quote:

Originally Posted by just_a_car

That sounds like a 'fouling shot' issue.

What is that?

billy · 12-07-2007, 10:47 PM

many times with a clean firearm the 1st shot will be off from the rest of the group because of bbl. fouling.
it does with my .22's

Onesonek · 12-07-2007, 11:09 PM

Quote:

Originally Posted by billy

many times with a clean firearm the 1st shot will be off from the rest of the group because of bbl. fouling.
it does with my .22's

That's why i alway fire atleast 3 (pending on barrel) fouling shots out of a freshly cleaned barrel.

As to the problem, I agree, it's likely a twist or crown issue.
Dave

SilverRun · 12-08-2007, 12:57 AM

Quote:

Originally Posted by nathangdad

The round is relatively slow moving and will keyhole at a certain distance. This is normal and many people welcome this as a performance enhancer as the bullet will stay in the target thus transmitting all hydrostatic shock energy to the target. Actually, any .45 acp round design will eventually keyhole.

Don't think I totally agree with this, but it is irrelevant at this point as the keyhole problem is solved.

billy · 12-08-2007, 06:42 AM

Quote:

Originally Posted by Onesonek

That's why i alway fire atleast 3 (pending on barrel) fouling shots out of a freshly cleaned barrel.

As to the problem, I agree, it's likely a twist or crown issue.
Dave

my cz452 doesnt like being perfectly clean.
i always get it spotless after a session but it takes about a dozen shots to get where it likes to be.

big boomer · 12-23-2007, 06:40 PM

most comp shooters foul their barrel before a match for the reason that the first shot will be different than the rest otherwise. Some do not clean their barrel till the end of the season or until groups drop off for this reason. bullet key holing may ammo problem too. As long as its no longer a problem no biggie.

samuel · 12-23-2007, 09:05 PM

Quote:

Originally Posted by nathangdad

The round is relatively slow moving and will keyhole at a certain distance. This is normal and many people welcome this as a performance enhancer as the bullet will stay in the target thus transmitting all hydrostatic shock energy to the target. Actually, any .45 acp round design will eventually keyhole.

This is absolutely someones emagination or a direct attempt to post misinformation or outright lies.I have seen many .45ACP,s fired out to 200yds and no sign of keyholing using bullets from185gr to 230gr and speeds from 700fps to 1100fps+.Besides that ,if a .45 of any kind started to tumble,being at low speed anyway it would be slowed so quickly or stopped period there wouldnt be anything left to cause hydrostatic shock which takes high velocity to create which is something a .45ACP doesnt have to begin with.Show me any substanciation that a .45ACP will eventually keyhole.I cant show that it doesnt because since it doesnt they never write about it,I bet if it were true and not your emagination they would write about it.BS is BS,show me the facts. sam.

By the way,the place I saw .40,s and.45,s fired 200yds was rhe police academy in,Tenn..They were practicing laying down suppressive fire to aid a fellow officer that was pinned down.At 200yds the bullets were still hitting point first. sam.

nathangdad · 12-24-2007, 03:55 AM

You cannot build a theoretically perfect bullet exactly
balanced around a centerline from tip to base with
perfect curvature toward the tip. IF any bullet stays airborne long enough stabilizing spin will slow and the tip will begin to move off center. At that moment air pressure is greater on one side of the bullet and less on the other side. Thus what begins as a slight wobble will become tumbling (keyholing).

The reason people believe any bullet will not keyhole is that the bullet slows and gravity brings it to the ground before keyholing can occur.

The .45 ACP is a short, heavy bullet leaving the barrel at a relatively slow speed without a great deal of
stabilizing spin. Therefore it can keyhole before hitting the ground. The lesson to be learned is
the greater the diameter of the bullet to the length of the bullet, the slower the velocity, and a reduced rate of stabilizing spin will hasten the keyholing effect. Beyond the .45 ACP you might wish to consider some of the black powder projectiles as obvious candidates for keyholing (especially the larger bore rifles).

However, as I mentioned in a prior post, keyholing is not an entirely undesired effect when maximum stopping power is desired. A heavy projectile keyholing will generate a larger entrance cavity and will generally not shoot through the target thus imparting full energy to the target.

Johnny_Revolver · 12-24-2007, 04:39 AM

Something an old guy lectured me about: If you use a piece of A4 with a target printed on it, and then staple it to a board, if there is big arse holes in the board, the bullets won`t punch a nice clean hole, they are ragged.

This was at a rifle range, when folk are trying to refine accuracy and this trait isn`t wanted at all.

He suggested quite rightly, that the paper target stapled to cardboard then the backing board is your best option.

It`s either that or what`s been discussed above, but to my thinking a piece of cardboard isn`t gonna cost you anything to try.

12-05-2007, 07:21 AM	#1
micallen Member Join Date: Nov 2007 Location: South Carolina Posts: 35	Keyholing - Ammo? or Gun ?? Are certain types of ammo more prone to keyholing, or is that a gun issue?? I'm speaking specifically about a .45 ACP.

12-05-2007, 07:30 AM	#2
billy spiritual counselor Join Date: Jul 2006 Location: a secret lab on the shores of lake titicaca Posts: 12,157 Images: 9 Blog Entries: 146	i would say the gun. __________________

12-05-2007, 08:02 AM	#3
nathangdad Senior Member Join Date: Nov 2007 Posts: 2,475	.45 230 grain bullet will keyhole at distance The round is relatively slow moving and will keyhole at a certain distance. This is normal and many people welcome this as a performance enhancer as the bullet will stay in the target thus transmitting all hydrostatic shock energy to the target. Actually, any .45 acp round design will eventually keyhole.

12-07-2007, 10:47 PM	#13
billy spiritual counselor Join Date: Jul 2006 Location: a secret lab on the shores of lake titicaca Posts: 12,157 Images: 9 Blog Entries: 146	many times with a clean firearm the 1st shot will be off from the rest of the group because of bbl. fouling. it does with my .22's __________________

12-24-2007, 03:55 AM	#19
nathangdad Senior Member Join Date: Nov 2007 Posts: 2,475	Physics 101 You cannot build a theoretically perfect bullet exactly balanced around a centerline from tip to base with perfect curvature toward the tip. IF any bullet stays airborne long enough stabilizing spin will slow and the tip will begin to move off center. At that moment air pressure is greater on one side of the bullet and less on the other side. Thus what begins as a slight wobble will become tumbling (keyholing). The reason people believe any bullet will not keyhole is that the bullet slows and gravity brings it to the ground before keyholing can occur. The .45 ACP is a short, heavy bullet leaving the barrel at a relatively slow speed without a great deal of stabilizing spin. Therefore it can keyhole before hitting the ground. The lesson to be learned is the greater the diameter of the bullet to the length of the bullet, the slower the velocity, and a reduced rate of stabilizing spin will hasten the keyholing effect. Beyond the .45 ACP you might wish to consider some of the black powder projectiles as obvious candidates for keyholing (especially the larger bore rifles). However, as I mentioned in a prior post, keyholing is not an entirely undesired effect when maximum stopping power is desired. A heavy projectile keyholing will generate a larger entrance cavity and will generally not shoot through the target thus imparting full energy to the target.

12-05-2007, 11:29 AM	#6
lefty o Senior Member Join Date: Mar 2002 Location: mn Posts: 4,806	keyholing is not normal, and is indicitive of a problem. 2 normal culprits are bullet weight that is unsuitable for the barrels twist rate, or the crown is damaged.

12-06-2007, 10:00 AM	#7
micallen Member Join Date: Nov 2007 Location: South Carolina Posts: 35	I may call Taurus today.

12-06-2007, 02:19 PM	#8
rondog Senior Member Join Date: Aug 2007 Location: Parker, CO Posts: 1,334	What were you shooting at? Some types of target paper will give you a hole that is torn, not punched cleanly. Maybe try a piece of cardboard and see if you get different results.

12-07-2007, 02:57 PM	#10
micallen Member Join Date: Nov 2007 Location: South Carolina Posts: 35	UPDATE: I fired 15 rounds today (into a cardboard box). Actually, I fired 10, and the local expert marksman here fired the other 5. Good news is: NO keyholing. I can assume it was becaus of the thin paper last time. Bad news: 1st shot high, all other shots low. For me and the "expert." Same thing Monday when I shot it for the 1st time.

12-23-2007, 06:40 PM	#17
big boomer Senior Member Join Date: Dec 2007 Location: Minn. Posts: 980	most comp shooters foul their barrel before a match for the reason that the first shot will be different than the rest otherwise. Some do not clean their barrel till the end of the season or until groups drop off for this reason. bullet key holing may ammo problem too. As long as its no longer a problem no biggie.

12-24-2007, 04:39 AM	#20
Johnny_Revolver Gun Liker Join Date: May 2005 Location: Queensland, Australia Posts: 1,209 Blog Entries: 6	Something an old guy lectured me about: If you use a piece of A4 with a target printed on it, and then staple it to a board, if there is big arse holes in the board, the bullets won`t punch a nice clean hole, they are ragged. This was at a rifle range, when folk are trying to refine accuracy and this trait isn`t wanted at all. He suggested quite rightly, that the paper target stapled to cardboard then the backing board is your best option. It`s either that or what`s been discussed above, but to my thinking a piece of cardboard isn`t gonna cost you anything to try. __________________ It`s a good life, provided you don`t weaken.