Re: 300 Win Mag Load Development Help Needed
I have not tried the TTSX in any of my rifles yet, but have had good luck with the 100gn TSX in .257 cal and 140gn in .284 cal.
That said, in my .300WM, I tried the 180gn NBT with RL22/9.5M & BR2 primers and never could get accuracy under .6". Then I tried them with H4350/9.5M and @ 69.0gn I got .370" and 3094fps (avg). This load shot good for me at 650yds. I let my son, three nephews and brother-in-law shoot it at that distance. Only my son had previous shooting experience that far, but the nephews and B-I-L are hooked! They all could consistently ring the 12X18" gong I made and boy were they'a grinning!
I tried the 190gn SMK with RL25 and WLRM (and 9.5M) primers but the best I got was a .5" (once) and couldn't duplicate it.
Then I tried the 180gn SMK with RL22/9.5M OAL:2.8950" and @ 75.5gn's I'm getting an average velocity of 3133fps and accuracy is running in the .3's.
Still got more testing to do (180NBT/w RL25 & 190SMK/w RL22 and others) but will share this info if you like.
Oh, I did try some 165gn NBT's I had on hand the day after I bought the rifle. I used H4350/9.5M OAL: 2.8925". I tried 71/72/73gns and accuracy and velocity ran; .585" @ 3244fps (71.0gn), .4175" @ 3269fps (72.0gn) and .6340"@3296fps (73.0gn).
Hope all this helps and encourages you to keep trying. The .300WinMag is an awesome cartridge and capable of very good accuracy. JohnnyK.