In the .22 Hornet you're never going to see much difference, even in hot weather, because you can't get enough 1680 in the case to cause any pressure "symptoms." But in the .17 Hornet there's plenty of room still left in the case even with 20-grain bullets in max loads, and yes, you can see signs of high pressure in hot weather.
Seafire doesn't have any idea of what the pressure is in his .204 load, because there's no loading data for 1680 in the .204. He likes to experiment with various powders and often works up to where pressure "appear" safe. It may be a very low-pressure load, but nobody knows.
just for clarification, it is in a 20 Practical, not a 204 Ruger.
I found some data in a cast bullet manual for the 223 and the 221 Fireball that I used as a basis and worked up... also cross referencing some 222 data...utilizing bullets at 40 grains..
took those and worked up some with the 32 V Max and the 24 grain NTX...
tested 20 grains of 1680 with the 32 V Max and 22 grains with the 24 NTX...
these have proven to be safe in the Ruger chambered in the 20 Practical....no pressure signs or issues...
so now need to get over to the range and see how they group on a target when shooting off the bench... they shot good enough off the hood of my vehicle,..
will bring along the chronograph to see what kind of MV they yield...
These are not probably top velocity loads... but I have enough powder for roughly 700 rounds so I thought I'd give her a whirl....
got some BLC2, some TAC, some H4198 and H 322 loads to test them out against...
since there is little to no data for the 20 Practical, this is sorta how you have to figure it out anyway...
my ballistic's lab is in the shop...
