Originally Posted by 21Glock
Thanks for the input. I also didn't mention that I recently got a KKM 6" barrel for my Gen 4 20 as well, so I won't be shooting these loads in my stock barrel.
I'm trying minimize any smileys, pressure wise and still get high end speed.
I'm sort of leaning toward AA#9 or Longshot as well. I've heard some good things about the VitaV powders, but boy are they expensive!!
I have a handful of KKM barrels and I think they make a really good product.
If your experience tracks mine, you will see a marked improvement in velocity potential with that longer barrel, especially with the slower powders.
On the smiley and case support thing, I am not certain this amounts to much. My experience seems to indicate that smiles are not as much a factor of where the ramp enters the chamber (at least in the later 10mm barrels) or the ultimate size of the chamber and more related to how the timing of the gun is affected in the upper reaches of pressure. That 6" barrel has to help with the unlock timing, so it likely will help keep smiles at bay while loading in the twilight zone.
What I am unsure about is the difference between a stock 6" hunting barrel and an aftermarket unit with tighter chamber and a steeper ramp and when smiles start showing up. I suspect there is some marginal difference, but in the realm of precision I load, have my doubts it is a first order concern.
In any case, for me, I have done my nuke loading and am now back to loads that top out somewhere in the 1250fps range with the stock barrel (with 180gr slugs); in that category, with the components I am using, smiles are not on the agenda if the gun is working right, so I find my KKM barrels ended up being nice paperweights.