Load Specifications
Load data in caliber .300 Rem. SA Ultra Mag. with .308 | 150gr | Lapua Mega bullet and 98 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Power Pro 2000-MR, ReloadSwiss RS 52 and ReloadSwiss RS 60.
Important Notice: DO NOT go below Minimum Charge or above Maximum Charge. Since we have no control over the equipment and components used, any responsibility and liability for the results achieved is rejected.
Only powders/loads that match the current filter criteria are displayed: max pressure of a load ≤ 90% of max. standardized pressure, fill rate ≥ 80% and propellant combustion ≥ 95%. Use the sliders above the tables to adjust these thresholds.
Charge: Powder weight in grains. Start with the minimum load and work up carefully.
FR (Fill Rate): Case fill as a percentage. Values above 100% mean compressed loads.
MaxP / %: Maximum chamber pressure in bar and as a percentage of the standardized maximum for this caliber.
V(0): Muzzle velocity in feet per second (fps) at the standardized barrel length.
z (Powder Burn): Estimated propellant combustion percentage at bullet exit.
A valid access license is required to use the Personalized Load Calculator.
You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 88% | 55,564 psi | 85% | 2881 fps | 100% |
| Accurate 2460 | <<locked>> | 86% | 57,696 psi | 89% | 2956 fps | 100% |
| Accurate 2495 | <<locked>> | 94% | 56,942 psi | 88% | 2946 fps | 100% |
| Accurate 2520 | <<locked>> | 88% | 55,840 psi | 86% | 2966 fps | 100% |
| Accurate 4064 | <<locked>> | 96% | 56,391 psi | 87% | 2986 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 48,559 psi | 75% | 2936 fps | 97.8% |
| Accurate LT-30 | <<locked>> | 84% | 58,146 psi | 89% | 2867 fps | 100% |
| Accurate LT-32 | <<locked>> | 84% | 58,552 psi | 90% | 2894 fps | 100% |
| ADI AR 2206H | <<locked>> | 92% | 58,073 psi | 89% | 3025 fps | 99.7% |
| ADI AR 2208 | <<locked>> | 96% | 55,463 psi | 85% | 2963 fps | 99.1% |
| ADI AR 2219 | <<locked>> | 82% | 55,825 psi | 86% | 2949 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 90% | 57,159 psi | 88% | 2976 fps | 100% |
| Alliant AR-Comp | <<locked>> | 90% | 57,421 psi | 88% | 2959 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 84% | 55,405 psi | 85% | 3038 fps | 99.8% |
| Alliant Power Pro 2000-MR | <<locked>> | 94% | 57,783 psi | 89% | 3143 fps | 99.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 98% | 58,450 psi | 90% | 3038 fps | 100% |
| Alliant Reloder-10x | <<locked>> | 86% | 58,726 psi | 90% | 2933 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 94% | 55,811 psi | 86% | 3009 fps | 99.3% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 47,935 psi | 74% | 2943 fps | 97.8% |
| Alliant Reloder-17ᴾ | <<locked>> | 100% | 55,608 psi | 86% | 3104 fps | 99.9% |
| Baschieri & Pellagri 106 | <<locked>> | 84% | 57,479 psi | 88% | 2864 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 92% | 57,943 psi | 89% | 3038 fps | 99.2% |
| Bofors RP3 | <<locked>> | 96% | 55,521 psi | 85% | 3002 fps | 99.9% |
| Bofors RP7ᴾ | <<locked>> | 100% | 55,999 psi | 86% | 2956 fps | 95.7% |
| Hodgdon Benchmark | <<locked>> | 88% | 55,680 psi | 86% | 2910 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 90% | 56,405 psi | 87% | 3009 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 88% | 58,334 psi | 90% | 3110 fps | 99.5% |
| Hodgdon H322 | <<locked>> | 86% | 58,073 psi | 89% | 2979 fps | 100% |
| Hodgdon H335 | <<locked>> | 84% | 55,622 psi | 86% | 2956 fps | 100% |
| Hodgdon H380 | <<locked>> | 96% | 56,927 psi | 88% | 3015 fps | 98.6% |
| Hodgdon H4895 | <<locked>> | 92% | 58,595 psi | 90% | 3035 fps | 99.9% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 44,034 psi | 68% | 2822 fps | 98.4% |
| Hodgdon LEVERevolution | <<locked>> | 94% | 57,754 psi | 89% | 3071 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,853 psi | 54% | 1801 fps | 100% |
| Hodgdon VARGET | <<locked>> | 92% | 56,347 psi | 87% | 2986 fps | 99.8% |
| IMR 3031 | <<locked>> | 92% | 58,117 psi | 89% | 3022 fps | 100% |
| IMR 4064 | <<locked>> | 96% | 58,465 psi | 90% | 2999 fps | 99.5% |
| IMR 4166 Enduron | <<locked>> | 92% | 55,535 psi | 85% | 2923 fps | 96.2% |
| IMR 4198 | <<locked>> | 86% | 58,697 psi | 90% | 2890 fps | 100% |
| IMR 4451 Enduronᴾ | <<locked>> | 100% | 58,175 psi | 89% | 2995 fps | 96.7% |
| IMR 4831ᴾ | <<locked>> | 100% | 46,209 psi | 71% | 2874 fps | 97.4% |
| IMR 4895 | <<locked>> | 94% | 57,203 psi | 88% | 3045 fps | 99.7% |
| IMR 8208 XBR | <<locked>> | 90% | 57,159 psi | 88% | 2976 fps | 100% |
| Lovex D073.5 | <<locked>> | 86% | 57,856 psi | 89% | 2969 fps | 100% |
| Lovex D073.6 | <<locked>> | 92% | 57,638 psi | 89% | 3002 fps | 100% |
| Lovex S060 | <<locked>> | 92% | 57,899 psi | 89% | 2949 fps | 99.7% |
| Lovex S062 | <<locked>> | 96% | 57,914 psi | 89% | 2999 fps | 100% |
| Lovex S065ᴾ | <<locked>> | 100% | 53,476 psi | 82% | 2930 fps | 97.3% |
| Norma 200 | <<locked>> | 82% | 58,479 psi | 90% | 2904 fps | 100% |
| Norma 201 | <<locked>> | 92% | 56,623 psi | 87% | 2966 fps | 100% |
| Norma 202 | <<locked>> | 92% | 57,101 psi | 88% | 2972 fps | 100% |
| Norma 203B | <<locked>> | 96% | 58,566 psi | 90% | 3051 fps | 99.8% |
| Norma URPᴾ | <<locked>> | 100% | 48,385 psi | 74% | 2930 fps | 97.6% |
| Ramshot Big Game | <<locked>> | 94% | 55,419 psi | 85% | 3022 fps | 99.5% |
| Ramshot TAC | <<locked>> | 90% | 58,030 psi | 89% | 2995 fps | 98.2% |
| Ramshot Wild Boar | <<locked>> | 90% | 57,246 psi | 88% | 3015 fps | 99.6% |
| Ramshot X-Terminator | <<locked>> | 88% | 58,566 psi | 90% | 2979 fps | 99.6% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,230 psi | 54% | 1844 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 86% | 57,072 psi | 88% | 2966 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 96% | 57,377 psi | 88% | 2989 fps | 97.3% |
| ReloadSwiss RS 52 | <<locked>> | 92% | 55,985 psi | 86% | 3077 fps | 99.3% |
| ReloadSwiss RS 60 | <<locked>> | 98% | 55,579 psi | 86% | 3114 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 48,153 psi | 74% | 2953 fps | 97.4% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 49,313 psi | 76% | 2979 fps | 96.9% |
| Rottweil R 901 | <<locked>> | 90% | 57,769 psi | 89% | 2956 fps | 100% |
| Rottweil R 902 | <<locked>> | 94% | 57,087 psi | 88% | 2966 fps | 100% |
| Rottweil R 903 | <<locked>> | 98% | 55,056 psi | 85% | 2989 fps | 99.8% |
| Rottweil R 907ᴾ | <<locked>> | 100% | 55,999 psi | 86% | 2956 fps | 95.7% |
| Shooters World Long Rifleᴾ | <<locked>> | 100% | 53,476 psi | 82% | 2930 fps | 97.3% |
| Shooters World Match Rifle | <<locked>> | 92% | 57,638 psi | 89% | 3002 fps | 100% |
| Shooters World Precision | <<locked>> | 96% | 57,914 psi | 89% | 2999 fps | 100% |
| Shooters World Tactical Rifle | <<locked>> | 84% | 56,797 psi | 87% | 2933 fps | 99.9% |
| SNPE Vectan BA6 1/2 | <<locked>> | 82% | 57,986 psi | 89% | 2608 fps | 100% |
| SNPE Vectan SP 10 | <<locked>> | 82% | 56,086 psi | 86% | 2959 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 98% | 57,029 psi | 88% | 3051 fps | 99.6% |
| SNPE Vectan SP 3 | <<locked>> | 84% | 56,246 psi | 87% | 2910 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 90% | 56,130 psi | 86% | 2966 fps | 98.3% |
| SNPE Vectan SP 9 | <<locked>> | 92% | 56,507 psi | 87% | 2995 fps | 99.6% |
| SNPE Vectan Tubal 3000 | <<locked>> | 92% | 58,639 psi | 90% | 2910 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 98% | 58,537 psi | 90% | 2904 fps | 100% |
| SNPE Vectan Tubal 7000ᴾ | <<locked>> | 100% | 54,070 psi | 83% | 2881 fps | 95.9% |
| Somchem S321 | <<locked>> | 86% | 55,013 psi | 85% | 2963 fps | 100% |
| Somchem S335 | <<locked>> | 92% | 57,725 psi | 89% | 2907 fps | 100% |
| Somchem S341 | <<locked>> | 90% | 55,593 psi | 86% | 2963 fps | 99.5% |
| Somchem S355 | <<locked>> | 98% | 55,651 psi | 86% | 2989 fps | 99.7% |
| Somchem S365ᴾ | <<locked>> | 100% | 43,047 psi | 66% | 2874 fps | 99.3% |
| Vihtavuori N130 | <<locked>> | 88% | 58,378 psi | 90% | 2877 fps | 100% |
| Vihtavuori N133 | <<locked>> | 92% | 58,552 psi | 90% | 2894 fps | 100% |
| Vihtavuori N135 | <<locked>> | 94% | 56,391 psi | 87% | 2933 fps | 100% |
| Vihtavuori N140 | <<locked>> | 94% | 57,783 psi | 89% | 2949 fps | 100% |
| Vihtavuori N150ᴾ | <<locked>> | 100% | 57,406 psi | 88% | 2969 fps | 100% |
| Vihtavuori N160ᴾ | <<locked>> | 100% | 50,836 psi | 78% | 2930 fps | 98% |
| Vihtavuori N530 | <<locked>> | 90% | 58,001 psi | 89% | 2979 fps | 100% |
| Vihtavuori N540 | <<locked>> | 94% | 55,912 psi | 86% | 2946 fps | 100% |
| Vihtavuori N550ᴾ | <<locked>> | 100% | 49,951 psi | 77% | 2933 fps | 97.7% |
| Winchester 6.5 StaBALLᴾ | <<locked>> | 100% | 51,996 psi | 80% | 2917 fps | 99.6% |
| Winchester 748 | <<locked>> | 90% | 57,363 psi | 88% | 3028 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 92% | 56,405 psi | 87% | 3005 fps | 99.8% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 80% | 43,381 psi | 67% | 2694 fps | 100% |
| Accurate 2460 | <<locked>> | 80% | 47,239 psi | 73% | 2799 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 35,853 psi | 55% | 2598 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 42,366 psi | 65% | 2746 fps | 99.6% |
| Accurate 4064 | <<locked>> | 80% | 33,881 psi | 52% | 2579 fps | 99% |
| Accurate 4350 | <<locked>> | 94% | 39,421 psi | 61% | 2759 fps | 95.5% |
| Accurate LT-30 | <<locked>> | 80% | 51,692 psi | 80% | 2779 fps | 100% |
| Accurate LT-32 | <<locked>> | 80% | 52,069 psi | 80% | 2802 fps | 100% |
| ADI AR 2206H | <<locked>> | 80% | 39,740 psi | 61% | 2694 fps | 96.9% |
| ADI AR 2208 | <<locked>> | 84% | 38,334 psi | 59% | 2644 fps | 95.7% |
| ADI AR 2219 | <<locked>> | 80% | 52,257 psi | 80% | 2897 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 80% | 41,756 psi | 64% | 2710 fps | 98.5% |
| Alliant AR-Comp | <<locked>> | 80% | 41,176 psi | 63% | 2717 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 80% | 48,414 psi | 74% | 2917 fps | 99.1% |
| Alliant Power Pro 2000-MR | 51.6 gr | 82% | 38,522 psi | 59% | 2759 fps | 95.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 32,967 psi | 51% | 2556 fps | 95.7% |
| Alliant Reloder-10x | <<locked>> | 80% | 48,747 psi | 75% | 2792 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 38,072 psi | 59% | 2677 fps | 95.8% |
| Alliant Reloder-16 | <<locked>> | 94% | 39,798 psi | 61% | 2769 fps | 95.5% |
| Alliant Reloder-17 | <<locked>> | 86% | 34,751 psi | 53% | 2674 fps | 95.5% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 50,691 psi | 78% | 2769 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 38,725 psi | 60% | 2687 fps | 95.3% |
| Bofors RP3 | <<locked>> | 80% | 32,343 psi | 50% | 2552 fps | 95.6% |
| Bofors RP7 | <<locked>> | 98% | 52,779 psi | 81% | 2904 fps | 95% |
| Hodgdon Benchmark | <<locked>> | 80% | 43,801 psi | 67% | 2710 fps | 99.2% |
| Hodgdon BL-C2 | <<locked>> | 80% | 40,118 psi | 62% | 2726 fps | 98.7% |
| Hodgdon CFE223 | <<locked>> | 80% | 44,063 psi | 68% | 2861 fps | 97.5% |
| Hodgdon H322 | <<locked>> | 80% | 47,819 psi | 74% | 2825 fps | 100% |
| Hodgdon H335 | <<locked>> | 80% | 48,646 psi | 75% | 2848 fps | 100% |
| Hodgdon H380 | <<locked>> | 86% | 41,002 psi | 63% | 2730 fps | 95.2% |
| Hodgdon H4895 | <<locked>> | 80% | 40,016 psi | 62% | 2707 fps | 97.5% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 34,171 psi | 53% | 2602 fps | 95.4% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 35,955 psi | 55% | 2664 fps | 96.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,846 psi | 40% | 1608 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 38,638 psi | 59% | 2661 fps | 97.1% |
| IMR 3031 | <<locked>> | 80% | 39,073 psi | 60% | 2713 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 37,869 psi | 58% | 2628 fps | 95.8% |
| IMR 4166 Enduron | <<locked>> | 90% | 52,156 psi | 80% | 2867 fps | 95.5% |
| IMR 4198 | <<locked>> | 80% | 49,182 psi | 76% | 2756 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 96% | 51,561 psi | 79% | 2887 fps | 95.3% |
| IMR 4831 | <<locked>> | 94% | 37,985 psi | 58% | 2710 fps | 95.1% |
| IMR 4895 | <<locked>> | 80% | 36,448 psi | 56% | 2651 fps | 96% |
| IMR 8208 XBR | <<locked>> | 80% | 41,756 psi | 64% | 2710 fps | 98.5% |
| Lovex D073.5 | <<locked>> | 80% | 47,094 psi | 72% | 2802 fps | 99.7% |
| Lovex D073.6 | <<locked>> | 80% | 38,435 psi | 59% | 2677 fps | 99.1% |
| Lovex S060 | <<locked>> | 80% | 40,263 psi | 62% | 2638 fps | 97.1% |
| Lovex S062 | <<locked>> | 80% | 35,201 psi | 54% | 2579 fps | 97% |
| Lovex S065 | <<locked>> | 94% | 44,672 psi | 69% | 2772 fps | 95.3% |
| Norma 200 | <<locked>> | 80% | 55,071 psi | 85% | 2858 fps | 100% |
| Norma 201 | <<locked>> | 80% | 39,044 psi | 60% | 2654 fps | 98% |
| Norma 202 | <<locked>> | 80% | 38,986 psi | 60% | 2667 fps | 99.6% |
| Norma 203B | <<locked>> | 80% | 35,027 psi | 54% | 2608 fps | 95.4% |
| Norma URP | <<locked>> | 94% | 39,842 psi | 61% | 2759 fps | 95.4% |
| Ramshot Big Game | <<locked>> | 82% | 37,014 psi | 57% | 2674 fps | 95.8% |
| Ramshot TAC | <<locked>> | 82% | 44,599 psi | 69% | 2762 fps | 95.5% |
| Ramshot Wild Boar | <<locked>> | 80% | 41,017 psi | 63% | 2730 fps | 97.2% |
| Ramshot X-Terminator | <<locked>> | 80% | 45,266 psi | 70% | 2759 fps | 98% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,063 psi | 40% | 1647 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 46,804 psi | 72% | 2802 fps | 99.8% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 47,427 psi | 73% | 2825 fps | 95.1% |
| ReloadSwiss RS 52 | 48.8 gr | 80% | 36,898 psi | 57% | 2717 fps | 95.3% |
| ReloadSwiss RS 60 | 49.5 gr | 80% | 30,443 psi | 47% | 2562 fps | 96.2% |
| ReloadSwiss RS 62 | <<locked>> | 96% | 42,163 psi | 65% | 2838 fps | 95.9% |
| ReloadSwiss RS 70 | <<locked>> | 96% | 43,091 psi | 66% | 2851 fps | 95% |
| Rottweil R 901 | <<locked>> | 80% | 42,917 psi | 66% | 2710 fps | 99.8% |
| Rottweil R 902 | <<locked>> | 80% | 37,072 psi | 57% | 2602 fps | 97.5% |
| Rottweil R 903 | <<locked>> | 82% | 32,619 psi | 50% | 2552 fps | 95.4% |
| Rottweil R 907 | <<locked>> | 98% | 52,779 psi | 81% | 2904 fps | 95% |
| Shooters World Long Rifle | <<locked>> | 94% | 44,672 psi | 69% | 2772 fps | 95.3% |
| Shooters World Match Rifle | <<locked>> | 80% | 38,435 psi | 59% | 2677 fps | 99.1% |
| Shooters World Precision | <<locked>> | 80% | 35,201 psi | 54% | 2579 fps | 97% |
| Shooters World Tactical Rifle | <<locked>> | 80% | 49,632 psi | 76% | 2822 fps | 99.4% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 54,984 psi | 85% | 2569 fps | 100% |
| SNPE Vectan SP 10 | <<locked>> | 80% | 52,649 psi | 81% | 2907 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 36,056 psi | 55% | 2657 fps | 95.6% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 49,748 psi | 77% | 2815 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 82% | 42,554 psi | 65% | 2730 fps | 95.5% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 38,406 psi | 59% | 2661 fps | 96.5% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 40,712 psi | 63% | 2621 fps | 99.7% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 33,547 psi | 52% | 2480 fps | 99.3% |
| SNPE Vectan Tubal 7000 | <<locked>> | 98% | 50,778 psi | 78% | 2828 fps | 95.2% |
| Somchem S321 | <<locked>> | 80% | 44,918 psi | 69% | 2792 fps | 99.2% |
| Somchem S335 | <<locked>> | 80% | 40,147 psi | 62% | 2621 fps | 99.9% |
| Somchem S341 | <<locked>> | 80% | 39,436 psi | 61% | 2674 fps | 96.7% |
| Somchem S355 | <<locked>> | 82% | 33,576 psi | 52% | 2559 fps | 95.4% |
| Somchem S365 | <<locked>> | 90% | 31,227 psi | 48% | 2589 fps | 95.8% |
| Vihtavuori N130 | <<locked>> | 80% | 46,093 psi | 71% | 2700 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 40,872 psi | 63% | 2625 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 36,216 psi | 56% | 2598 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 36,956 psi | 57% | 2602 fps | 99.5% |
| Vihtavuori N150 | <<locked>> | 80% | 29,936 psi | 46% | 2448 fps | 95.6% |
| Vihtavuori N160 | <<locked>> | 92% | 39,189 psi | 60% | 2707 fps | 95% |
| Vihtavuori N530 | <<locked>> | 80% | 41,684 psi | 64% | 2707 fps | 98.6% |
| Vihtavuori N540 | <<locked>> | 80% | 35,491 psi | 55% | 2582 fps | 98.9% |
| Vihtavuori N550 | <<locked>> | 94% | 41,075 psi | 63% | 2766 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 34,925 psi | 54% | 2579 fps | 95.8% |
| Winchester 748 | <<locked>> | 80% | 40,799 psi | 63% | 2746 fps | 99% |
| Winchester StaBALL Match | <<locked>> | 80% | 37,579 psi | 58% | 2661 fps | 96.9% |
Recommended = one of the top powders for this cartridge and bullet combination.
ᴾ possible press load - work up slowly to this load while watching for signs of excessive pressure.
This overview compares 98 powders for .300 Rem. SA Ultra Mag. loaded with the .308 | 150gr | Lapua Mega. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,143 fps; across all powders the maximum-charge window runs from 1,801 fps to 3,143 fps. Accurate 4350 gives the best case fill at 100 %, and 98 of the 98 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 54–90 %, leaving at least 10 % headroom. The 150.0 gr projectile in 0.308" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. Accurate 4350, Alliant Reloder-16, Alliant Reloder-17 reach 100 % fill or more at maximum charge, so these are compressed loads: they need a long drop tube to seat cleanly and react sensitively to the case capacity of your own brass lot. Alliant Power Pro 2000-MR, ReloadSwiss RS 52, ReloadSwiss RS 60 rank at the top here: for .300 Rem. SA Ultra Mag. with the .308 | 150gr | Lapua Mega they combine a high case fill with complete burn and sit in the upper velocity band. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.