In loading the 556 is there any significant difference between CFE223 and BL-C(2)?

BL-C (2) is reportedly more Temp sensitive. I haven't tried it personally though.

I've used a ton of CFE223 with excellent results and it meters very well.

Interesting.  Thanks!

Could it also be used in the 308?

I have also had the same thing happen with cfe 223, make sure you load and test on a warm day.

BLC (2) is a great powder, I've used it in 5.56, 7mm TCU and 308. I'm not sure if there is any comparison between the 2 technology wise as BLC(2) has been around for decades and CFE223 is relatively new.

I like BLC2 but it's a little dirtier than CFE. But on the down side BLC2 does gain pressure above 90 degrees and loose pressure below 20 degrees. I think it does better in the  .308 and 7mm08 due to case capacity. But I have a pretty sweet load with the 69gr nosler custom competition in the  5.56. I'm fixing to try the CFE with some 73 berger's and 75gr Hornady Amax bullets. Side note I think BLC2 works better in 5.56 chamber than the  .223rem chamber.  Now I tried BLC2 in the Grendel and the accuracy was crazy.  Between 65 and 75 degrees it shot like a dream but it would quickly spread out if you got out of that temperature range. I like to stay 0.5grs off max or the starting of flattened primers with BLC2.

BLC2 and CFE-223 are virtually identical in burn rates. They main difference is CFE-223 has a copper fouling reduction chemical added.

Maximum loads should be developed in the heat of summer, 90 degrees if possible. Those loads will be safe year round. Never allow your ammo to sit in direct sunlight. This holds true regardless of what powder you use.

Ammo exposed to direct sunlight on a hot summer day can easily reach 140 degrees F.if it remains there very long.