7383 in the blackout

[wiljen]

I was looking at load data and it seems that 4831 and 4350 are both right in the sweet spot for subsonics. It seems that 7383 would be right in there too. I'm getting ready to put together a few test loads and just wondered what others experience might be.

[Nobade]

It should get a heavy boolit to the speed you want but I bet you'll see a lot of vertical due to very incomplete burn. But that's just my guess - let us know how it works. It might be surprisingly effective, I sure didn't expect it to be so accurate in the 358 win but it shoots tiny groups in that gun.

-Nobade

[Jim]

Will, sorry for comin' in a week late.

Heavy boolits will provide the back pressure that 7383 needs to achieve a complete burn. Do you have that Lee 309-230-5R mold? That would be a good candidate for 7383 in the Blackout. I've found that a magnum primer helps a bit toward complete burn, too.

Have you seen my method for determining case density with 7383 by drilling out the primer pocket on a sacrificial case? I would suggest establishing CD and start with 98%.

A .30 caliber bullet in a .223 case is almost a tapered case like .38-55 or .45-70. I've found that I can not only go to 100% in calibers like that, quite often I can go to a compressed charge. You can't do that in pronounced bottlenecks, but I think the limited bottleneck in the Blackout would allow that.

Starting with 7383 in a new caliber, I first look for the top of the pressure window by ladder testing. When I find the spike point charge, I back down and then start back up looking for the sweet spot. That way, I don't over run the spike point.

I'd be real interested in hearing of your results. The Blackout is a whole new game for 7383.