ORIGINAL: sabotloader
I feel the weak link in your system is the pellets. I feel that it takes more fire to get them to fire. The colder the temp the hotter you are going to have to get them - Therefore I would suggest the Win 209's, which pellet you use doesn't seem in my mind to make a difference, when you are shooting a 100 grains of t7 pellets you are not really shooting 100 grains - you are shooting an equivelent load to 100 grains of Pyro or real BP.
I am not qualified to to make ajudgement on which pellet is better Pyro/t7 becuase I do not have enough experiance with them...
FYI,
The triple seven pellets are harder to ignite and are for 209 primers only.For cold weather I'd use the hottest primer I could find. The Pyrodex pellets have impregnated blackpowder on one end and can be ignited with #11 caps. Still the hotter the primer the better for cold weather reliability. I used Pyrodex pellets for a while with the Winchesters and never had an issue in cold weather. I shoot at the range like I would hunting. The coldest I've ever shot is 10-20 degrees. I've never had any issues with Pyrodex pellets except when I combined them with Powerbelts. The pellets didn't burn fast enough and ejected the Powerbelt and pellets without a complete burn. Only in Knights but I won't use PB's in anything now unless I use loose powder. I now use loose powder only in everything and have for 3 years.