First 1:10 is not particularly slow, and it has no problem stabilizing the 154's... That said, I don't shoot anything heavier than 139 SST and 140 BT's in ours and our go to bullets are the 120 BT's in most situations for deer sized game... They are flat shooting with great terminal ballistics and are pretty close to as accurate as the 139/140 class bullets... Some of the 154's shot very well out of our guns, but we also have .30/30 and .308 with 150's and 168's respectively and .243 and 7.62 on the bottom end... So there really is no point in pushing the load limit... The 120's can potentially out shoot the 154's because the lowest common denominator is this shooter. For the record we are getting very exciting results with CFE-223 powder in .223, .243, 7mm-08, and .308... Better velocity, lower dispersion and better accuracy... What's not to love! We shoot our 7 mils below max... But not too far below... Where as we max our .30 cals.