Joe pretty well summed up my concerns with the slower powders in cold weather. One simply needs to understand, these powders "Were Not Designed" for producing lower pressure, they "Were Designed" for pushing heavier loads @ full velocities without increasing pressures. My learning curve on this came about 25+ yrs ago. I had loaded up some 1¼oz #5 lead loads taken directly from the old DuPont handloaders guide @ about 1100 fps with 7k psi. I shot a few & checked a few paterns, wonderful load. Just to further check them out I went out & shot a few early season squirrels (I was predominately a .22RF man for squirrels) & they dispatched them with aploom. Opening day of duck season my son & I were hunting a wooded swamp. Temps had dropped into the high 20's & we had to break ice on the outer edges to get the boat back into the woods. Short story is those loads even @ 7K totally let me down. Every thing got out the bbl fortunately but without enough force to penertrate beyond the near side skin of a fairly short range greenhead.
"Slow Powders" get that way by increased grain size &/or heavier coatings of "Deterrants". Neither of these are conducive to good burning characteristics at low pressures & cold temps.
Anyone is of course free to ignore this at will, but please remember when, sometime in the future you have perhaps laid out a good deal of cash for a hunt of a lifetime, & upon a great opportunity, your gun says "Bloop", just let it cross your mind "2-Piper Told Me So".
