.450 Bushmaster Twist Rate
Recommended twist, the factory rates you will find, and a calculated stability chart for the bullets .450 Bushmaster actually shoots.
.450 Bushmaster uses wide .452" bullets that are short relative to their bore diameter, so factory barrels use a slow 1:24" or 1:16" twist.
1:24" is the original specification and stabilizes 245 to 260 grain supersonic loads with plenty of margin. Newer 1:16" barrels are chosen when shooters also want to run heavy 395 grain subsonic loads.
For reference, a 250 grain bullet at 2200 fps in a 1:24" barrel comes out at a stability factor of 2.46.
.450 Bushmaster twist rate chart
Required twist is the rate that puts each bullet at a stability factor of 1.5. The remaining columns show the stability factor you actually get in each barrel. Click any row to load that bullet into the calculator below.
| Bullet | Length | Velocity | Twist needed | Sg at 1:16" | Sg at 1:24" | Calculator |
|---|---|---|---|---|---|---|
| 245 gr InterLock | 0.820"est. | 2200 fps | 1:37.3" | 8.16 | 3.63 | |
| 250 gr FTX | 0.960"est. | 2200 fps | 1:30.7" | 5.54 | 2.46 | |
| 395 gr subsonic | 1.320"est. | 1050 fps | 1:25.1" | 3.68 | 1.64 |
Green is properly stable (1.5 and above), amber is marginal, red will not stabilize. Figures are calculated with the Miller twist rule at standard sea-level conditions, the same way the mobile app does it. Velocity is listed for reference and is not part of the calculation. Lengths marked "est." are approximate for that bullet class; stability is very sensitive to length, so measure your own bullet and check it in the calculator above before relying on a marginal result.
Check your own .450 Bushmaster load
Pre-filled with a typical .450 Bushmaster bullet. Change the bullet dimensions or twist to match your rifle.
Bullet
Barrel
Conditions
Bullet length matters more than weight — measure it or take it from your load data rather than guessing.
Matches the app’s stable classification at standard atmosphere.
Twist recommendation
Working figures
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How twist rate works in .450 Bushmaster
A bullet in flight is trying to tumble. Air pressure on the nose creates a force that wants to flip it end over end, and the only thing preventing that is the spin the rifling gave it. Twist rate sets how much spin the bullet leaves with, so it sets which bullets your barrel can actually stabilize.
Length is the driver, not weight. Long, sleek, high-BC bullets are harder to stabilize than short stubby ones of the same mass, which is why two bullets of identical weight can have very different twist requirements. The Miller rule used here accounts for that directly, which is why every figure on this page is calculated from bullet length rather than looked up from weight alone.
Aim for a stability factor of 1.5 or better rather than merely clearing 1.0. The figures here use the mobile engine’s standard-atmosphere Sg formula. In the app, actual stability is corrected for temperature and station pressure: colder, denser air reduces stability.
Twist rate for other cartridges
Recommended twist, the factory rates you will actually find, and a calculated stability chart for the bullets each cartridge shoots.
.308
6.5 CM
.223
5.56
AR-15
8.6 BLK
.22-250
.300 PRC
6.5 PRC
.300 Win Mag
.30-06
.243
6 CM
6 ARC
6.5 Grendel
.300 BLK
7mm Rem Mag
7 PRC
.270
.277 Fury
25 CM
.224 Valkyrie
.350 Legend
.204
7.62x39
6.8 Western
.17 HMR
Barrel sorted? Next comes the trajectory — see the full .450 Bushmaster ballistics chart.
Comparing shoulder kick across loads? See .450 Bushmaster recoil in ft-lbs.
Want the raw calculator without a cartridge preset? Use the twist rate calculator.
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