Key Holing 9 MM

[AJ]

A friend was shooting some 130 grain cast over 3.5 grains of Bullseye. He had a Beretta 92, a Taurus and a S&W 39. In the first two he had multiple key holed shots in the target at 15 yards. With the 39, he had none. I shot five of his rounds in my 39 and while they grouped alright, I had one key hole.

I was shooting 147 grain cast over 3.5 grains of Bullseye. None of my rounds key holed in my 39. He tried the loading in his Beretta and it function fine with no key holes.

Best guesses are welcome. My first thought is he needs to up the powder to maybe 4.0 grains.

 

[rockquarry]

Upping the charge would certainly be worth a try.

What is the measured-with-micrometer bullet diameter?

 

[AJ]

Upping the charge would certainly be worth a try.

What is the measured-with-micrometer bullet diameter?

No clue as to the measurement. Will ask him if he knows.

 

[max]

I loaded some lead 9's once and they were sliding along the rifling and not spinning. Either too hot or too small or a bit of both.

 

[rockquarry]

Regarding bullet diameter...some 9mm pistols may shoot well with .355" or .356" cast bullets, but I've found a larger diameter, .357" or .358" usually works better as for accuracy and for the prevention of leading, at least in a Beretta, a Sig, and a Walther. As with cast bullets in rifles, the largest diameter bullet that will allow a cartridge to be chambered without difficulty will usually be the best choice.

 

[505Gibbs]

The dia. may be the 'key' to the issue over all else though the load does sound awful light.

 

[Fishinfool]

Agree with the above posters. I would bet a combination of undersized bullet, and not enough powder charge to bump the undersized bullet up enough to let it grip the rifling. I'll bet he had some leading in the barrel to clean out. I have always had my best luck with the 9mm using as big a diameter bullet as will allow chambering, casting hard, and using a gas check on problem guns that lead.

Larry

 

[stansdds]

9x19 bore and chamber dimensions seem to vary a whole lot. Now it could be too light of a powder charge and the bullet is not sealing the bore or the rifling twist is not stabilizing it, but it could also be the bullet is too small in diameter for the Beretta and Canik. Lead bullets sometimes do not do will in barrels that have shallow rifling.

 

[rockquarry]

What is a Canik?

 

[M29since14]

My older Beretta 92F does best with .357" jacketed bullets, so there is no doubt in my mind it would prefer at least that big, or bigger, in a cast bullet. I have a friend who uses cast bullets as big as .359" in his S&W 3913, but he does not push them too hard. I'd certainly try at least a .357" bullet and see if that helps with the keyholing issue.

(Edit) I'm guessing of course, but I don't see the powder charge as a problem. I use 4.0 of 231, also a bit light, and have never had a keyhole, that I recall. I'd guess bullet diameter. Might check the barrel for leading, good crown, etc.

 

[Alk8944]

Since they were cast bullets of "unknown provenance", I assume, the bullets may have internal flaws resulting in imbalance. Or they could be undersized. Never assume that commercial cast bullets, or private cast, are the diameter the seller/provider says they are! I have seen cast bullets as much as .005" under the claimed diameter. This applies to commercial jacketed, plated or coated bullets too.

Worst case I have seen is some European "bagged" jacketed bullets bought at a gun show that were supposed to be for .30 Luger. They measured .302". I have had them for probably 40 years, still in the bag I bought them in. I still have no idea what cartridge/gun they would be appropriate for!!!

 

[Nevada Ed]

Regarding bullet diameter...some 9mm pistols may shoot well with .355" or .356" cast bullets, but I've found a larger diameter, .357" or .358" usually works better as for accuracy and for the prevention of leading, at least in a Beretta, a Sig, and a Walther. As with cast bullets in rifles, the largest diameter bullet that will allow a cartridge to be chambered without difficulty will usually be the best choice.

+1 on the beretta
but my C9 does not like coated 125gr bullet over .356 dia.
The .358 dia samples would not chamber in my 3.5" pistol
but they work great in me .38 special.

and yes, that 3.5 gr load of Bullseye is way low !!

 

[murphydog]

What is a Canik?

It's a Turkish company that makes a variety of semi-automatic pistols. There is an extensive writeup of these in the current American Handgunner magazine.

 

[Luke Duke]

Ive never had good luck shooting cast in a 9mm. But the limited amount of marginal accuracy has been with over sized bullets .357 or.358 cast fairly hard. How the barrel is rifled makes a huge impact. Polygonal will not shoot cast. I had a Berreta once that had an immensely oversized bore. Wouldn't shoot anything accurately.

 

[Warboar]

My guess would be undersized bullets. Slugging the bore of the guns would tell you what the diameter is. I've seen some 9mm barrels as large as .358 while most are around .355-.356.
Typically it's best to shoot cast bullets that are sized .002 over the bore size. I shoot bullets anywhere from .002 to .004 over what my bore size is and have great results. I cast my own and shoot cast exclusively in all my handguns. I get great accuracy out of them. Just need to size them to your gun. If your shooting a revolver you size them to your cylinder.

 

[AJ]

What is a Canik?

I was mistaken it is a Taurus, not a Canik. This is Canik's website Canik USA - Superior Firearms Have shot a couple and was impressed.

 

[AJ]

My friend is using 356 bullets He prefers these.

 

[rockquarry]

My friend is using 356 bullets He prefers these.

Were they measured with a micrometer or is that diameter from a box label? As mentioned in my first post, an undersized bullet may be the entire problem or at least part of it.

 

[glenwolde]

I can't speak to the Beretta but Taurus 9mm barrels tend to run large. He "prefers" .356? Is that because of his superior results?

Ok that's a bit harsh but it would seem his preference is unfounded.

 

[AJ]

Were they measured with a micrometer or is that diameter from a box label? As mentioned in my first post, an undersized bullet may be the entire problem or at least part of it.

The box has .356 and he has measured them at .356.

I can't speak to the Beretta but Taurus 9mm barrels tend to run large. He "prefers" .356? Is that because of his superior results?

Ok that's a bit harsh but it would seem his preference is unfounded.

What is the size of the "large" barrels of the Taurus? Could it have something to do with the barrel length as both the Beretta and the Taurus have longer barrels than the 39? With other powder charges the guns has shot fine. The gentleman in question is a good shot, he shot on the 2nd Marine Division Team when in the Corps.

He and I discussed this last night. He is going to up the powder charge and see if that rectifies the problem.