key-holeing

handgunner-1 · April 17, 2006, 12:27 AM

I have a Beretta Cougar 8000-F in 9mm. I load 124 gr. Redline lead bullets ahead of 3.3 grs. Clays, going up and down in 1/10's grs. and consistently get key-holeing. I'm at the point of considering getting rid of the gun in disgust. I use the same loads in my Sig 239 with superb accuracy and no key-holeing. Any help or info would be greatly appreciated - thanks in advance - handgunner-1

handgunner-1 · April 17, 2006, 12:42 AM

check bullet for undersizing

Leftoverdj · April 17, 2006, 12:51 AM

Put the other way, check the bore for being oversized.

**Unclenick** · April 17, 2006, 12:45 PM

Two other things to look for:

1). A really off-axis crown (uneven all around the muzzle) will do this. Recrowning the barrel solves it.

2). I have twice run into barrels that were made with the rifling depth unequal around the barrel. One was a DW 4" .357 barrel that keyholed even at 50 ft. Because that gun's barrels are interchangeable and the owner had a kit of barrels, we quickly found it did fine with its 2" and 6" barrels in the same frame shooting the same ammo. I looked in the muzzle and saw the rifling looked uneven. I slugged it and found the rifling on one side was .002" deep and .006" deep on the opposite side. This obviously unbalances the bullet.

Second one was a S&W model 41. .22's just keyholing like mad.

So, take a look for these. If you have either problem, see whether the factory will replace the barrel for free? They often will with an obvious defect, even if the gun is used.

Nick

**44 AMP** · April 18, 2006, 05:46 PM

Some 9mm guns will not do well with lead bullets. No matter what you do. Other 9mms don't seem to care. Or care as much

Try some jacketed loads in your Berretta, 124gr? you said, see if you get the keyholing. If not, then just confine that gun to jacketed ammo, (for accuracy). Alternative, slug your barrel. Match bullet to barrel diameter.

But try some other ammo, some guns just won't shoot some things well.

geronimo13 · April 18, 2006, 06:18 PM

Being a total newby to guns and reloading (but a rabid reader), it seems the bullet isn't stabilizing with the rifling. They say (at least w/ar's) if the barrel twist is not right keyholeing occurs. As stated above maybe different jacketing or bullet weight would change this and cause the bullet to stabilize.

Russ5924 · April 18, 2006, 07:02 PM

I have a Taurus 906 9MM revolver with a short barrel that does it with mild reloads. I shoot factory loads all is OK I shoot my mild reloads back to keyholes, I think it is the short barrel and the bullet not getting enough spin to stabilize was using 115G FMJ Winchester bullets and 4G of Winchester 231 in the reloads.

I was going to try a different powder but never did was just as easy to buy WWB as much as I shot it??

**Unclenick** · April 18, 2006, 11:14 PM

Yup. Too slow will do it, too. Manufacturers of bullets usually put only one twist rate down for one of their bullets, but don't tell you that it assumes full velocity loads for that chambering and bullet weight. It is indeed the RPM that determines bullet stability. You would need a different twist for every muzzle velocity to keep the exact same RPM for every load. Fortunately the stability factor can usually be anwhere from about 1.1 to about 3 and still work at least sort of OK.

Nick

Jim Watson · April 19, 2006, 10:31 AM

Try another bullet. Gun flaws like Unclenick describes are extremely rare, mismatch of cheap cast bullets is extremely common. The unusual part is that those bullets shoot well in your Sig-Sauer not that they don't in the Beretta.

Leftoverdj · April 19, 2006, 12:17 PM

It's gotta be the right bullet to try. It's commonly suggested to load 9mm with .355-.356 diameter bullets and that's flat wrong for most barrels. .357-.358 is needed for most barrels.

9mms have a very fast twist, 1-9", if memory serves. The typical 125 grain bullets have limited bearing surface. Most people load the 9mm too hot for lead and the bullets can strip. A bullet in the 150 grain range at 800-900 fps is a lot more likely to give good results.

April 17, 2006, 12:27 AM	#1
handgunner-1 Junior Member Join Date: January 30, 2006 Posts: 6	key-holeing I have a Beretta Cougar 8000-F in 9mm. I load 124 gr. Redline lead bullets ahead of 3.3 grs. Clays, going up and down in 1/10's grs. and consistently get key-holeing. I'm at the point of considering getting rid of the gun in disgust. I use the same loads in my Sig 239 with superb accuracy and no key-holeing. Any help or info would be greatly appreciated - thanks in advance - handgunner-1

April 17, 2006, 12:42 AM	#2
handgunner-1 Junior Member Join Date: January 30, 2006 Posts: 6	key-holeing check bullet for undersizing

April 17, 2006, 12:45 PM	#4
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,743	Two other things to look for: 1). A really off-axis crown (uneven all around the muzzle) will do this. Recrowning the barrel solves it. 2). I have twice run into barrels that were made with the rifling depth unequal around the barrel. One was a DW 4" .357 barrel that keyholed even at 50 ft. Because that gun's barrels are interchangeable and the owner had a kit of barrels, we quickly found it did fine with its 2" and 6" barrels in the same frame shooting the same ammo. I looked in the muzzle and saw the rifling looked uneven. I slugged it and found the rifling on one side was .002" deep and .006" deep on the opposite side. This obviously unbalances the bullet. Second one was a S&W model 41. .22's just keyholing like mad. So, take a look for these. If you have either problem, see whether the factory will replace the barrel for free? They often will with an obvious defect, even if the gun is used. Nick __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

April 18, 2006, 05:46 PM	#5
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 30,484	9mm Lead Some 9mm guns will not do well with lead bullets. No matter what you do. Other 9mms don't seem to care. Or care as much Try some jacketed loads in your Berretta, 124gr? you said, see if you get the keyholing. If not, then just confine that gun to jacketed ammo, (for accuracy). Alternative, slug your barrel. Match bullet to barrel diameter. But try some other ammo, some guns just won't shoot some things well.

April 18, 2006, 11:14 PM	#8
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,743	Yup. Too slow will do it, too. Manufacturers of bullets usually put only one twist rate down for one of their bullets, but don't tell you that it assumes full velocity loads for that chambering and bullet weight. It is indeed the RPM that determines bullet stability. You would need a different twist for every muzzle velocity to keep the exact same RPM for every load. Fortunately the stability factor can usually be anwhere from about 1.1 to about 3 and still work at least sort of OK. Nick __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

April 17, 2006, 12:51 AM	#3
Leftoverdj Senior Member Join Date: October 15, 2004 Posts: 934	Put the other way, check the bore for being oversized.

April 18, 2006, 06:18 PM	#6
geronimo13 Member Join Date: April 7, 2006 Posts: 41	Being a total newby to guns and reloading (but a rabid reader), it seems the bullet isn't stabilizing with the rifling. They say (at least w/ar's) if the barrel twist is not right keyholeing occurs. As stated above maybe different jacketing or bullet weight would change this and cause the bullet to stabilize.

April 18, 2006, 07:02 PM	#7
Russ5924 Senior Member Join Date: February 18, 2005 Posts: 1,874	I have a Taurus 906 9MM revolver with a short barrel that does it with mild reloads. I shoot factory loads all is OK I shoot my mild reloads back to keyholes, I think it is the short barrel and the bullet not getting enough spin to stabilize was using 115G FMJ Winchester bullets and 4G of Winchester 231 in the reloads. I was going to try a different powder but never did was just as easy to buy WWB as much as I shot it??

April 19, 2006, 10:31 AM	#9
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 19,185	Try another bullet. Gun flaws like Unclenick describes are extremely rare, mismatch of cheap cast bullets is extremely common. The unusual part is that those bullets shoot well in your Sig-Sauer not that they don't in the Beretta.

April 19, 2006, 12:17 PM	#10
Leftoverdj Senior Member Join Date: October 15, 2004 Posts: 934	It's gotta be the right bullet to try. It's commonly suggested to load 9mm with .355-.356 diameter bullets and that's flat wrong for most barrels. .357-.358 is needed for most barrels. 9mms have a very fast twist, 1-9", if memory serves. The typical 125 grain bullets have limited bearing surface. Most people load the 9mm too hot for lead and the bullets can strip. A bullet in the 150 grain range at 800-900 fps is a lot more likely to give good results.