IMR 4166 vs 4064

[JackSprat]

I stopped by the sporting goods store the otherday,and noticed they had the IMR 4166 selling about $3 dollars cheaper per pound than IMR 4064..I went ahead and bought a pound because I remember reading somewhere that it's basicaly an inproved 4064..I mainly got it to try in my 7mm08 with 139,and 140s,but I'm concidering trying it in my 243 with 95,and 100s..It's the same burn speed as IMR4064 from what I gather,and both powders are listed in Hodgdon data for use in 243 with 100s but I'm thinking it may be a little too fast burning..I may be wrong though,because I know 4064 is pretty versitile...I can't help but wonder why it was cheaper if it's susposed to be better...Has anyone else tried this in place of 4064?

 

[horsey300]

I stopped by the sporting goods store the otherday,and noticed they had the IMR 4166 selling about $3 dollars cheaper per pound than IMR 4064..I went ahead and bought a pound because I remember reading somewhere that it's basicaly an inproved 4064..I mainly got it to try in my 7mm08 with 139,and 140s,but I'm concidering trying it in my 243 with 95,and 100s..It's the same burn speed as IMR4064 from what I gather,and both powders are listed in Hodgdon data for use in 243 with 100s but I'm thinking it may be a little too fast burning..I may be wrong though,because I know 4064 is pretty versitile...I can't help but wonder why it was cheaper if it's susposed to be better...Has anyone else tried this in place of 4064?

Yup, the conversation wanders some, but it covers a variety of weights with 4166 as well as other experiments.
https://www.thehighroad.org/index.php?threads/87gr-vmax-loading-suggestions.823288/

 

[Tinybob]

I stopped by the sporting goods store the otherday,and noticed they had the IMR 4166 selling about $3 dollars cheaper per pound than IMR 4064..I went ahead and bought a pound because I remember reading somewhere that it's basicaly an inproved 4064..I mainly got it to try in my 7mm08 with 139,and 140s,but I'm concidering trying it in my 243 with 95,and 100s..It's the same burn speed as IMR4064 from what I gather,and both powders are listed in Hodgdon data for use in 243 with 100s but I'm thinking it may be a little too fast burning..I may be wrong though,because I know 4064 is pretty versitile...I can't help but wonder why it was cheaper if it's susposed to be better...Has anyone else tried this in place of 4064?

I've used 4166 in 243 loads from 58gr up to 100gr bullets. It loves mid-range loads. The best accuracy I had with 100gr Sierra or Speer was 0.4 MOA at 100yds. I got this with 35grs of 4166. I've not tried 4064 so I can't comment on the difference. I bought the 4166 on clearance from Natchez SS, 8lbs for $174(regular price said $270?).

 

[JO JO]

I have tried IMR 4166 for my 308, worked very well and burned clean too next I will try it for heavier 223 loads

The 308 I got the best results at midrange to upper midrange data

 

[Tinybob]

The very clean burning is something I forgot to mention.
Really the only accuracy node I've seen with 4166 is in the middle. All other powders I've tried will have at least two nodes through the charge range.I don't know if there is another accuracy node just beyond published max or not, I didn't go beyond. In my Ruger, I went to Max with 87gr VMAX, and didn't show any pressure signs.

I'm NOT encouraging you to go beyond max, just stating what I saw with my rifle.