I wanted to update the topic.
I was able to dig a few bullets out of the berm behind my target stand today. I was hoping to find some of the 9x39 so I could look at the jacket to see if they're getting tore up real bad from the porting.
No, it is not. You can clearly see the rifling, and the jacket looks fine.
Unfortunately, where we've had so much rain lately, it was too muddy to dig for long because of the clumpy orange clay, so I can only assume that this bullet had struck a rock and caused the mushrooming. I want to dig around some more to see if any of the others are mushrooming out similarly which would indicate that they're working better than expected at subsonic velocities, but I do suspect that this bullet probably did hit a rock. Still, at around 965 fps, that's respectable that it would mushroom out like even if it was a rock, or even hit a shoulder bone or whatever.
I also recovered a few 220 gr nosler blackout bullets for comparison.
OK, there is no comparison.
The 9x39 is whooping blackout ass all around. I have no doubt that the middle bullet had also hit a rock too. And it didn't mushroom out either, which I have seen with the blk before just deforming at the tip.
But the 9x39 is impressing me more the more that I fool with it. Not just with the round being easier to reload, and more quiet, and being able to use faster burning powders, but from the looks of this picture, is outperforming downrange too. velocities of the blk and the 9x39 are all similar. Around 965 fps for all of the ones below. In looking at the one on the far left, I may could even clean it up and reload and shoot it again
barrel porting question
Re: barrel porting question
I don't care what your chart says