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Gerry · November 10, 2012, 05:02 PM

Well max it, use Red Dot then

In all seriousness, I think powder can affect bullet stability to some degree - like trying to use too slow or fast a powder for a specific application. But many of the top Production IPSC grand masters are shooting all A's with 147gr bullets driven by powders like N320 without keyholing. And this is with CZs too, like the Shadow.

I can't see keyholing caused by too small a barrel for the size of bullet. It's usually the opposite. I'm shooting .358" home cast bullets, but lubed the ol'fashioned way in the lube groove. Another possibility is that you're just using too light a charge for the particular powder you're trying out. I suggest using a chrono to develop your loads if you aren't already. A charge good enough to at least make 125 to 130 power factor doesn't keyhole if all other factors are good.

The physics are pretty simple. You need the bullet to engage the rifling in order to spin the bullet to stabilize itself during its journey to the target - just like throwing a football. Sometimes bullet designs are just silly and don't have enough surface (driving) area to engage the rifling to the degree required. Multiple lube grooves on small 9mm bullets fall into this category.

Good luck, but in the end just do whatever works for you. Experimentation is one of the most rewarding aspects of this hobby & sport.

November 10, 2012, 05:02 PM	#22
Gerry Senior Member Join Date: December 24, 2010 Location: Canada Posts: 382	Well max it, use Red Dot then In all seriousness, I think powder can affect bullet stability to some degree - like trying to use too slow or fast a powder for a specific application. But many of the top Production IPSC grand masters are shooting all A's with 147gr bullets driven by powders like N320 without keyholing. And this is with CZs too, like the Shadow. I can't see keyholing caused by too small a barrel for the size of bullet. It's usually the opposite. I'm shooting .358" home cast bullets, but lubed the ol'fashioned way in the lube groove. Another possibility is that you're just using too light a charge for the particular powder you're trying out. I suggest using a chrono to develop your loads if you aren't already. A charge good enough to at least make 125 to 130 power factor doesn't keyhole if all other factors are good. The physics are pretty simple. You need the bullet to engage the rifling in order to spin the bullet to stabilize itself during its journey to the target - just like throwing a football. Sometimes bullet designs are just silly and don't have enough surface (driving) area to engage the rifling to the degree required. Multiple lube grooves on small 9mm bullets fall into this category. Good luck, but in the end just do whatever works for you. Experimentation is one of the most rewarding aspects of this hobby & sport. Last edited by Gerry; November 10, 2012 at 05:31 PM.