Load Specifications
Load data in caliber .450 Rigby with .458 | 450gr | NorthFork Bonded Core bullet and 94 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 60 and ReloadSwiss RS 52.
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.
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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>> | 86% | 49,763 psi | 86% | 2264 fps | 100% |
| Accurate 2460 | <<locked>> | 84% | 51,227 psi | 88% | 2323 fps | 100% |
| Accurate 2495 | <<locked>> | 92% | 49,893 psi | 86% | 2316 fps | 100% |
| Accurate 2520 | <<locked>> | 88% | 52,431 psi | 90% | 2375 fps | 100% |
| Accurate 4064 | <<locked>> | 94% | 49,748 psi | 86% | 2352 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 44,904 psi | 77% | 2352 fps | 97.8% |
| ADI AR 2206H | <<locked>> | 90% | 51,735 psi | 89% | 2379 fps | 99.6% |
| ADI AR 2208 | <<locked>> | 94% | 49,559 psi | 85% | 2333 fps | 98.9% |
| ADI Benchmark 8208 | <<locked>> | 88% | 51,227 psi | 88% | 2343 fps | 99.9% |
| Alliant AR-Comp | <<locked>> | 88% | 50,749 psi | 87% | 2326 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 82% | 49,197 psi | 85% | 2382 fps | 99.7% |
| Alliant Power Pro 2000-MR | <<locked>> | 92% | 50,821 psi | 88% | 2470 fps | 99.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 96% | 51,706 psi | 89% | 2395 fps | 99.9% |
| Alliant Reloder-10x | <<locked>> | 82% | 49,763 psi | 86% | 2267 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 92% | 49,371 psi | 85% | 2369 fps | 99.1% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 45,165 psi | 78% | 2359 fps | 98% |
| Alliant Reloder-17ᴾ | <<locked>> | 100% | 51,982 psi | 90% | 2490 fps | 99.9% |
| Baschieri & Pellagri 106 | <<locked>> | 82% | 51,735 psi | 89% | 2254 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 90% | 51,053 psi | 88% | 2388 fps | 98.9% |
| Bofors RP3 | <<locked>> | 96% | 51,793 psi | 89% | 2405 fps | 99.9% |
| Hodgdon Benchmark | <<locked>> | 86% | 50,401 psi | 87% | 2293 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 88% | 49,559 psi | 85% | 2365 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 86% | 51,227 psi | 88% | 2444 fps | 99.3% |
| Hodgdon H322 | <<locked>> | 84% | 51,837 psi | 89% | 2343 fps | 100% |
| Hodgdon H335 | <<locked>> | 82% | 49,327 psi | 85% | 2323 fps | 100% |
| Hodgdon H380 | <<locked>> | 94% | 50,154 psi | 86% | 2369 fps | 98.2% |
| Hodgdon H414ᴾ | <<locked>> | 100% | 48,588 psi | 84% | 2398 fps | 95.8% |
| Hodgdon H4895 | <<locked>> | 90% | 52,185 psi | 90% | 2388 fps | 99.8% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 41,234 psi | 71% | 2260 fps | 98.5% |
| Hodgdon LEVERevolution | <<locked>> | 92% | 50,459 psi | 87% | 2415 fps | 99.9% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,737 psi | 60% | 1411 fps | 100% |
| Hodgdon VARGET | <<locked>> | 90% | 50,328 psi | 87% | 2349 fps | 99.6% |
| IMR 3031 | <<locked>> | 90% | 51,430 psi | 89% | 2379 fps | 100% |
| IMR 4064 | <<locked>> | 94% | 52,156 psi | 90% | 2362 fps | 99.3% |
| IMR 4166 Enduron | <<locked>> | 90% | 49,864 psi | 86% | 2300 fps | 95.9% |
| IMR 4198 | <<locked>> | 82% | 50,415 psi | 87% | 2234 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 98% | 51,793 psi | 89% | 2356 fps | 96.2% |
| IMR 4831ᴾ | <<locked>> | 100% | 43,062 psi | 74% | 2306 fps | 97.5% |
| IMR 4895 | <<locked>> | 92% | 50,560 psi | 87% | 2395 fps | 99.5% |
| IMR 8208 XBR | <<locked>> | 88% | 51,227 psi | 88% | 2343 fps | 99.9% |
| Lovex D073.5 | <<locked>> | 84% | 50,981 psi | 88% | 2329 fps | 100% |
| Lovex D073.6 | <<locked>> | 90% | 50,560 psi | 87% | 2362 fps | 100% |
| Lovex S060 | <<locked>> | 90% | 52,170 psi | 90% | 2320 fps | 99.6% |
| Lovex S062 | <<locked>> | 94% | 51,532 psi | 89% | 2359 fps | 100% |
| Lovex S065ᴾ | <<locked>> | 100% | 50,488 psi | 87% | 2349 fps | 97.5% |
| Lovex S070ᴾ | <<locked>> | 100% | 47,877 psi | 83% | 2333 fps | 95.8% |
| Norma 201 | <<locked>> | 90% | 50,647 psi | 87% | 2336 fps | 99.9% |
| Norma 202 | <<locked>> | 90% | 50,923 psi | 88% | 2343 fps | 100% |
| Norma 203B | <<locked>> | 94% | 51,779 psi | 89% | 2402 fps | 99.6% |
| Norma URPᴾ | <<locked>> | 100% | 45,208 psi | 78% | 2349 fps | 97.8% |
| Ramshot Big Game | <<locked>> | 94% | 51,779 psi | 89% | 2421 fps | 99.5% |
| Ramshot TAC | <<locked>> | 88% | 51,445 psi | 89% | 2352 fps | 97.8% |
| Ramshot Wild Boar | <<locked>> | 88% | 50,459 psi | 87% | 2372 fps | 99.4% |
| Ramshot X-Terminator | <<locked>> | 86% | 52,243 psi | 90% | 2343 fps | 99.5% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 34,998 psi | 60% | 1444 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 84% | 50,923 psi | 88% | 2329 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 94% | 50,923 psi | 88% | 2356 fps | 96.8% |
| ReloadSwiss RS 52 | <<locked>> | 92% | 52,315 psi | 90% | 2467 fps | 99.4% |
| ReloadSwiss RS 60 | <<locked>> | 98% | 51,880 psi | 89% | 2497 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 44,628 psi | 77% | 2369 fps | 97.5% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 45,992 psi | 79% | 2385 fps | 96.9% |
| Rottweil R 901 | <<locked>> | 88% | 51,895 psi | 89% | 2323 fps | 100% |
| Rottweil R 902 | <<locked>> | 92% | 50,923 psi | 88% | 2329 fps | 99.9% |
| Rottweil R 903 | <<locked>> | 98% | 51,503 psi | 89% | 2395 fps | 99.8% |
| Shooters World Long Rifleᴾ | <<locked>> | 100% | 50,488 psi | 87% | 2349 fps | 97.5% |
| Shooters World Match Rifle | <<locked>> | 90% | 50,560 psi | 87% | 2362 fps | 100% |
| Shooters World Precision | <<locked>> | 94% | 51,532 psi | 89% | 2359 fps | 100% |
| Shooters World SW4350ᴾ | <<locked>> | 100% | 47,877 psi | 83% | 2333 fps | 95.8% |
| Shooters World Tactical Rifle | <<locked>> | 82% | 50,560 psi | 87% | 2300 fps | 99.8% |
| SNPE Vectan SP 11 | <<locked>> | 96% | 50,140 psi | 86% | 2408 fps | 99.4% |
| SNPE Vectan SP 3 | <<locked>> | 82% | 50,575 psi | 87% | 2283 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 88% | 49,414 psi | 85% | 2333 fps | 97.9% |
| SNPE Vectan SP 9 | <<locked>> | 90% | 50,212 psi | 87% | 2356 fps | 99.4% |
| SNPE Vectan Tubal 3000 | <<locked>> | 88% | 49,690 psi | 86% | 2251 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 96% | 52,272 psi | 90% | 2287 fps | 100% |
| SNPE Vectan Tubal 7000ᴾ | <<locked>> | 100% | 50,662 psi | 87% | 2310 fps | 96% |
| Somchem S321 | <<locked>> | 86% | 52,127 psi | 90% | 2375 fps | 100% |
| Somchem S335 | <<locked>> | 90% | 51,793 psi | 89% | 2290 fps | 100% |
| Somchem S341 | <<locked>> | 90% | 52,228 psi | 90% | 2372 fps | 99.5% |
| Somchem S355 | <<locked>> | 98% | 52,359 psi | 90% | 2395 fps | 99.8% |
| Somchem S365ᴾ | <<locked>> | 100% | 40,176 psi | 69% | 2306 fps | 99.4% |
| Vihtavuori N130 | <<locked>> | 84% | 49,864 psi | 86% | 2228 fps | 100% |
| Vihtavuori N133 | <<locked>> | 88% | 49,676 psi | 86% | 2241 fps | 100% |
| Vihtavuori N135 | <<locked>> | 92% | 50,038 psi | 86% | 2306 fps | 100% |
| Vihtavuori N140 | <<locked>> | 92% | 51,343 psi | 89% | 2323 fps | 100% |
| Vihtavuori N150 | <<locked>> | 98% | 50,459 psi | 87% | 2339 fps | 100% |
| Vihtavuori N160ᴾ | <<locked>> | 100% | 47,587 psi | 82% | 2349 fps | 98.1% |
| Vihtavuori N530 | <<locked>> | 88% | 51,576 psi | 89% | 2343 fps | 99.9% |
| Vihtavuori N540 | <<locked>> | 92% | 49,458 psi | 85% | 2323 fps | 100% |
| Vihtavuori N550ᴾ | <<locked>> | 100% | 46,499 psi | 80% | 2352 fps | 97.8% |
| Winchester 6.5 StaBALLᴾ | <<locked>> | 100% | 48,747 psi | 84% | 2343 fps | 99.6% |
| Winchester 748 | <<locked>> | 88% | 50,633 psi | 87% | 2382 fps | 100% |
| Winchester 760ᴾ | <<locked>> | 100% | 48,733 psi | 84% | 2398 fps | 95.8% |
| Winchester StaBALL Match | <<locked>> | 90% | 49,617 psi | 86% | 2365 fps | 99.7% |
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% | 41,365 psi | 71% | 2149 fps | 100% |
| Accurate 2460 | <<locked>> | 80% | 44,817 psi | 77% | 2238 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 33,808 psi | 58% | 2077 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 39,972 psi | 69% | 2198 fps | 99.8% |
| Accurate 4064 | <<locked>> | 80% | 32,010 psi | 55% | 2067 fps | 99.3% |
| Accurate 4350 | <<locked>> | 94% | 36,521 psi | 63% | 2211 fps | 95.7% |
| ADI AR 2206H | <<locked>> | 80% | 37,956 psi | 65% | 2159 fps | 97.4% |
| ADI AR 2208 | <<locked>> | 82% | 34,447 psi | 59% | 2077 fps | 95.5% |
| ADI Benchmark 8208 | <<locked>> | 80% | 39,958 psi | 69% | 2172 fps | 98.8% |
| Alliant AR-Comp | <<locked>> | 80% | 38,972 psi | 67% | 2172 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 80% | 46,166 psi | 80% | 2336 fps | 99.4% |
| Alliant Power Pro 2000-MR | 84.7 gr | 82% | 36,390 psi | 63% | 2215 fps | 95.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 31,299 psi | 54% | 2051 fps | 96.4% |
| Alliant Reloder-10x | <<locked>> | 80% | 46,847 psi | 81% | 2228 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 33,895 psi | 58% | 2100 fps | 95.6% |
| Alliant Reloder-16 | <<locked>> | 92% | 35,534 psi | 61% | 2178 fps | 95% |
| Alliant Reloder-17 | <<locked>> | 84% | 30,937 psi | 53% | 2103 fps | 95.1% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 48,544 psi | 84% | 2215 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 36,695 psi | 63% | 2156 fps | 95.8% |
| Bofors RP3 | <<locked>> | 80% | 30,530 psi | 53% | 2047 fps | 96.2% |
| Hodgdon Benchmark | <<locked>> | 80% | 42,003 psi | 72% | 2165 fps | 99.4% |
| Hodgdon BL-C2 | <<locked>> | 80% | 37,971 psi | 65% | 2185 fps | 99% |
| Hodgdon CFE223 | <<locked>> | 80% | 41,568 psi | 72% | 2293 fps | 97.8% |
| Hodgdon H322 | <<locked>> | 80% | 45,484 psi | 78% | 2257 fps | 100% |
| Hodgdon H335 | <<locked>> | 80% | 46,093 psi | 79% | 2277 fps | 100% |
| Hodgdon H380 | <<locked>> | 86% | 38,609 psi | 67% | 2185 fps | 95.6% |
| Hodgdon H414 | <<locked>> | 98% | 45,571 psi | 79% | 2349 fps | 95% |
| Hodgdon H4895 | <<locked>> | 80% | 38,189 psi | 66% | 2169 fps | 98% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 30,516 psi | 53% | 2047 fps | 95.1% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 34,142 psi | 59% | 2139 fps | 97.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,715 psi | 44% | 1257 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 36,883 psi | 64% | 2133 fps | 97.6% |
| IMR 3031 | <<locked>> | 80% | 37,144 psi | 64% | 2172 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 33,895 psi | 58% | 2060 fps | 95.6% |
| IMR 4166 Enduron | <<locked>> | 88% | 46,862 psi | 81% | 2254 fps | 95.1% |
| IMR 4198 | <<locked>> | 80% | 47,572 psi | 82% | 2198 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 96% | 48,805 psi | 84% | 2313 fps | 95.5% |
| IMR 4831 | <<locked>> | 94% | 35,534 psi | 61% | 2175 fps | 95.4% |
| IMR 4895 | <<locked>> | 80% | 34,635 psi | 60% | 2126 fps | 96.6% |
| IMR 8208 XBR | <<locked>> | 80% | 39,958 psi | 69% | 2172 fps | 98.8% |
| Lovex D073.5 | <<locked>> | 80% | 44,628 psi | 77% | 2244 fps | 99.8% |
| Lovex D073.6 | <<locked>> | 80% | 36,245 psi | 62% | 2146 fps | 99.4% |
| Lovex S060 | <<locked>> | 80% | 38,769 psi | 67% | 2113 fps | 97.6% |
| Lovex S062 | <<locked>> | 80% | 33,634 psi | 58% | 2067 fps | 97.5% |
| Lovex S065 | <<locked>> | 94% | 42,105 psi | 73% | 2221 fps | 95.6% |
| Lovex S070 | <<locked>> | 98% | 44,889 psi | 77% | 2287 fps | 95% |
| Norma 201 | <<locked>> | 80% | 37,260 psi | 64% | 2123 fps | 98.4% |
| Norma 202 | <<locked>> | 80% | 37,217 psi | 64% | 2136 fps | 99.8% |
| Norma 203B | <<locked>> | 80% | 33,272 psi | 57% | 2090 fps | 96% |
| Norma URP | <<locked>> | 94% | 37,420 psi | 65% | 2215 fps | 95.7% |
| Ramshot Big Game | <<locked>> | 80% | 32,750 psi | 56% | 2096 fps | 95.4% |
| Ramshot TAC | <<locked>> | 80% | 39,827 psi | 69% | 2169 fps | 95.1% |
| Ramshot Wild Boar | <<locked>> | 80% | 38,812 psi | 67% | 2185 fps | 97.5% |
| Ramshot X-Terminator | <<locked>> | 80% | 43,134 psi | 74% | 2211 fps | 98.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,078 psi | 45% | 1289 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 44,802 psi | 77% | 2244 fps | 99.9% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 44,701 psi | 77% | 2264 fps | 95.4% |
| ReloadSwiss RS 52 | 80.1 gr | 80% | 34,795 psi | 60% | 2175 fps | 95.9% |
| ReloadSwiss RS 60 | 81.4 gr | 80% | 28,950 psi | 50% | 2060 fps | 96.9% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 36,593 psi | 63% | 2224 fps | 95.1% |
| ReloadSwiss RS 70 | <<locked>> | 96% | 40,350 psi | 70% | 2283 fps | 95.1% |
| Rottweil R 901 | <<locked>> | 80% | 41,002 psi | 71% | 2165 fps | 99.9% |
| Rottweil R 902 | <<locked>> | 80% | 35,447 psi | 61% | 2083 fps | 97.9% |
| Rottweil R 903 | <<locked>> | 80% | 28,863 psi | 50% | 2001 fps | 95.2% |
| Shooters World Long Rifle | <<locked>> | 94% | 42,105 psi | 73% | 2221 fps | 95.6% |
| Shooters World Match Rifle | <<locked>> | 80% | 36,245 psi | 62% | 2146 fps | 99.4% |
| Shooters World Precision | <<locked>> | 80% | 33,634 psi | 58% | 2067 fps | 97.5% |
| Shooters World SW4350 | <<locked>> | 98% | 44,889 psi | 77% | 2287 fps | 95% |
| Shooters World Tactical Rifle | <<locked>> | 80% | 47,413 psi | 82% | 2257 fps | 99.5% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 32,010 psi | 55% | 2087 fps | 95.2% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 47,630 psi | 82% | 2244 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 37,753 psi | 65% | 2142 fps | 95.1% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 36,419 psi | 63% | 2133 fps | 96.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 38,986 psi | 67% | 2093 fps | 99.8% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 31,966 psi | 55% | 1985 fps | 99.6% |
| SNPE Vectan Tubal 7000 | <<locked>> | 98% | 47,500 psi | 82% | 2267 fps | 95.4% |
| Somchem S321 | <<locked>> | 80% | 42,641 psi | 74% | 2238 fps | 99.4% |
| Somchem S335 | <<locked>> | 80% | 38,377 psi | 66% | 2100 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 37,376 psi | 64% | 2146 fps | 97.1% |
| Somchem S355 | <<locked>> | 80% | 29,950 psi | 52% | 2011 fps | 95.3% |
| Somchem S365 | <<locked>> | 88% | 27,688 psi | 48% | 2034 fps | 95.4% |
| Vihtavuori N130 | <<locked>> | 80% | 44,179 psi | 76% | 2152 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 39,073 psi | 67% | 2093 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 34,345 psi | 59% | 2077 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 35,244 psi | 61% | 2083 fps | 99.7% |
| Vihtavuori N150 | <<locked>> | 80% | 28,427 psi | 49% | 1962 fps | 96.3% |
| Vihtavuori N160 | <<locked>> | 92% | 36,883 psi | 64% | 2172 fps | 95.4% |
| Vihtavuori N530 | <<locked>> | 80% | 39,755 psi | 69% | 2165 fps | 98.9% |
| Vihtavuori N540 | <<locked>> | 80% | 33,808 psi | 58% | 2073 fps | 99.2% |
| Vihtavuori N550 | <<locked>> | 92% | 36,027 psi | 62% | 2175 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 31,024 psi | 53% | 2024 fps | 95.2% |
| Winchester 748 | <<locked>> | 80% | 38,638 psi | 67% | 2201 fps | 99.3% |
| Winchester 760 | <<locked>> | 98% | 45,687 psi | 79% | 2352 fps | 95% |
| Winchester StaBALL Match | <<locked>> | 80% | 35,534 psi | 61% | 2133 fps | 97.3% |
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 94 powders for .450 Rigby loaded with the .458 | 450gr | NorthFork Bonded Core. ReloadSwiss RS 60 delivers the highest muzzle velocity at 2,497 fps; across all powders the maximum-charge window runs from 1,411 fps to 2,497 fps. Accurate 4350 gives the best case fill at 100 %, and 94 of the 94 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (400 MPa), the top charges use 60–90 %, leaving at least 10 % headroom. The 450.0 gr projectile in 0.458" calls for a 1:6.0 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 60, ReloadSwiss RS 52 rank at the top here: for .450 Rigby with the .458 | 450gr | NorthFork Bonded Core 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.