Re: 300wm 175smk
175 GR. SIE HPBT Hodgdon H1000 .308" 3.300" 77.0 2820 43,100 CUP 82.0C 3008 51,800 CUP
175 GR. SIE HPBT Winchester Supreme 780 .308" 3.300" 72.4 2886 52,600 PSI 77.0 3047 61,800 PSI
175 GR. SIE HPBT Hodgdon H4831 .308" 3.300" 72.0 2843 46,600 CUP 76.5 3006 53,100 CUP
175 GR. SIE HPBT Hodgdon Hybrid 100V .308" 3.300" 65.0 2837 49,900 PSI 70.5 3068 62,300 PSI
175 GR. SIE HPBT Hodgdon H4350 .308" 3.300" 66.0 2832 45,800 CUP 71.0 2992 52,700 CUP
175 GR. SIE HPBT Hodgdon H414 .308" 3.300" 63.0 2830 48,200 CUP 67.5 2972 53,300 CUP
175 GR. SIE HPBT Winchester 760 .308" 3.300" 63.0 2830 48,200 CUP 67.5 2972 53,300 CUP
175 GR. SIE HPBT IMR IMR 4007 SSC .308" 3.300" 64.2 2809 52,000 PSI 68.3 2963 61,000 PSI
This data is posted from Hodgdon's Data Center. It appears that, when you compare 175 SMK loads to 190 SMK loads, you gain less than 100 FPS but give up a bit on BC. You will also burn even more powder with the 175 and I'm not sure the extra expense would be worth the results.
IMHO, you should stick to 190 or larger bullets in the 300 WM.