Use only X-terminator for my 223
Have been using X-terminator powder for seveal years now for my 223 bolt and my son's AR 15s and it is my powder of choice! Found it easy to get 3400 fps with Speer 50 gr TNTs in my Ruger (26" bbl) and 1/2" groups. Now shooting 50 gr Hornady SX (can no longer get the TNTs close enough to the lands for good accuracy but the SXs work well) at 3300 fps with the same level of accuracy. This powder shoots clean as powder fouling for high volume P-dog shooting is not a problem. With 3000+ rounds through the barrel, copper fouling really is much anymore either but is why the throat is geting so long.
Living in SE Idaho, I shoot a lot in the winter(teens) and summer (90+) with the same powder charge and have not noticed pressure problems. Some day I will pull out the chronograph for velocities in the winter to compare to summer velocities.
In my son's ARs we use because it produces the best velocities with 52 and 55 gr bullets, way better than with BLC-2, H335, Varget or Reloader 15. And with good accuaccy. Note that in my Ruger, X-terminator gave higher velocities and better accuracy than these other powders when I did load development with the SX bullets. It also meters very consistently for high volume reloading needs.
Best of all, I can buy this powder at a local store for under $14.00 a pound. Give it a try, I think you will like the powder