Shooting It — Recoil, Optics, Zero, and What the Accuracy Claims Are Worth

Volume 2 summarises why the .450 Bushmaster is a 200-yard cartridge, and the cartridge dive’s Volume 5 makes the full downrange case for every factory load. This volume is about hitting things inside 200 yards with an AR-15 in this calibre, and specifically with mine: a home-built rifle with a 16-inch Bear Creek Arsenal barrel, a Vector Optics Paragon 3-15×50 on a Primary Arms offset mount, and a Luth-AR MBA-3 stock (Volume 1 §1.8).

5.1 Correction, 19 October 2026

⚠ Correction (19 October 2026). Every path table in this volume as first published on 17 September 2026 was computed with a sight height of zero, although the text said 1.5 inches. The solver accepted the sight height and never used it: it zeroed the bore line, not the line of sight. The defect was found while building the .450 Bushmaster cartridge dive, whose corrected solver now reproduces Hornady’s, Federal’s and Remington’s own published trajectories. The tables below are recomputed with it, and the ballistic coefficient is now Hornady’s own published .210 instead of the .2112 this dive had fitted to Hornady’s velocity table (the two give the same velocities within 4 fps; using the maker’s figure keeps this dive and the cartridge dive on one basis).

What changed, for the 250 gr FTX at 2,200 fps:

Table 1 — What changed, for the 250 gr FTX at 2,200 fps

	As published 17 Sep 2026	Corrected
150-yd zero, highest point	+2.7 in at 75 yd	+2.0 in at 100 yd
150-yd zero, at 200 yd	−5.6 in	−5.1 in
150-yd zero, at 250 / 300 yd	−15.0 / −29.1 in	−14.0 / −27.6 in
150-yd zero, point-blank (8 in zone)	about 185 yd	about 191 yd
Best zero for an 8 in zone	150 yd	175 yd, point-blank about 209 yd
100-yd zero, at 200 yd	−10.5 in	−9.0 in
200-yd zero, at 100 yd	+5.2 in	+4.5 in
Hold at 100 yd to zero at 150 (§5.10)	+2.5 in	+2.0 in (1.5 in sight height)
10 mph drift at 200 yd	10.0 in	10.1 in (BC change only)

The errors are half an inch to an inch and a half. None of the volume’s conclusions changes: zero long, treat 200 yards as the limit, and respect the wind. One piece of advice did change in practice: the old §5.10 told a reader to set the rifle 2.5 inches high at 100 yards, which on the corrected model zeroes it at about 160 yards, not 150. The corrected figure is 2.0 inches.

5.2 Zero at 150, or 175

The reflex on a big slow cartridge is a 100-yard zero. For this load it wastes range. All figures are for Hornady’s 250 gr FTX at its published 2,200 fps (a 20-inch number; §5.5), BC .210, 1.5-inch sight height, standard air at 59 °F.

100-yard zero:

Table 2 — 100-yard zero:

Range	Velocity	Energy	Path
25	2,103	2,455	−0.3”
50	2,009	2,242	+0.3”
75	1,918	2,043	+0.5”
100	1,831	1,861	0.0
150	1,664	1,538	−2.9”
200	1,511	1,268	−9.0”
250	1,373	1,047	−18.9”

150-yard zero:

Table 3 — 150-yard zero:

Range	Velocity	Energy	Path
25	2,103	2,455	+0.2”
50	2,009	2,242	+1.3”
75	1,918	2,043	+1.9”
100	1,831	1,861	+2.0” (highest point)
125	1,746	1,693	+1.3”
150	1,664	1,538	0.0
175	1,586	1,396	−2.1”
200	1,511	1,268	−5.1”
250	1,373	1,047	−14.0”
300	1,252	871	−27.6”

175-yard zero:

Table 4 — 175-yard zero:

Range	Path
50	+1.9”
100	+3.2” (highest point)
150	+1.8”
175	0.0
200	−2.7”
250	−11.0”

200-yard zero:

Table 5 — 200-yard zero:

Range	Path
50	+2.6”
100	+4.5”
125	+4.5” (highest point)
150	+3.8”
200	0.0
250	−7.6”

The 100-yard zero gives range away for nothing. It is 9 inches low at 200 yards, which turns the outer edge of the cartridge’s useful range into a holdover problem.

The 200-yard zero is the interesting wrong answer. It sits 4.5 inches high from 100 to 125 yards, which puts the bullet outside an 8-inch vital zone at exactly the distances most deer are shot at.

⭐ The 150 and 175-yard zeros are both right, for slightly different shooters. For an 8-inch vital zone (never more than 4 inches high or low):

Table 6 — ⭐ The 150 and 175-yard zeros are both right, for slightly different shooters. For an 8-inch vital zone (never more than 4 inches high or low)

Zero	Highest point	Stays in the zone to
150 yd	+2.0” at 100	about 191 yd
175 yd	+3.2” at 100	about 209 yd (the longest of any zero)

A 175-yard zero is the formal maximum point-blank range, the same answer the cartridge dive reaches. A 150-yard zero gives up about 18 yards at the far end to keep the bullet within two inches of the crosshair at every distance up to 175. For a rifle that will mostly be shot at deer inside 150 yards, the 150-yard zero is the one this volume recommends; a hunter who sees longer field-edge shots loses nothing real by choosing 175. Either way the hold is dead on to about 190 yards.

5.3 Recoil

The .450 Bushmaster has a reputation for being a hard-kicking cartridge. Against a .223 it certainly is. Against the things it actually replaces, it is not.

Free recoil energy, computed for a 9 to 10 pound rifle, which is roughly where mine should land with a heavy barrel, a 15-inch rail, a 3-15×50 scope and a bipod (it has not been weighed; Volume 1 §1.8):

Table 7 — Free recoil energy, computed for a 9 to 10 pound rifle, which is roughly where mine should land with a heavy barrel, a 15-inch rail, a 3-15×50 scope and a bipod (it has not been weighed; Volume 1 §1.8)

Rifle weight	Free recoil
9 lb	16.2 – 17.8 ft-lbf
10 lb	14.6 – 16.0 ft-lbf

⚠ The range comes from an assumed powder charge, because this dive publishes no load data. The calculation spans 32 to 40 grains of propellant; the bullet and velocity are Hornady’s published figures. The charge weight is the only guessed input, and it moves the answer by under 2 ft-lbf, so the conclusion is not sensitive to it.

In context, all at a common weight:

Table 8 — In context, all at a common weight

Cartridge	Free recoil	Muzzle energy
.223 Remington, 55 gr	2.9 ft-lbf	1,282 ft-lbf
.308 Winchester, 150 gr	13.6 ft-lbf	2,649 ft-lbf
.450 Bushmaster, 250 gr	18.0 ft-lbf	2,687 ft-lbf
.45-70, 300 gr standard pressure	21.8 ft-lbf	2,355 ft-lbf
12 ga 438 gr rifled slug	28.3 ft-lbf	2,522 ft-lbf
12 ga 383 gr rifled slug	27.3 ft-lbf	2,756 ft-lbf

⭐ The .450 Bushmaster recoils about a third less than the 12-gauge slug gun it was bought to replace, and delivers more energy than either slug load. For a hunter coming from a slug gun, which in Michigan’s old limited firearms deer zone was very often the alternative, the .450 Bushmaster is the softer rifle. The two slug loads are the ones in my own equipment record.

Three things about this configuration reduce the felt impulse further, and felt recoil is not free recoil:

• A gas-operated action spreads the impulse in time. The carrier’s rearward travel against the buffer spring absorbs and delays part of it (Volume 7 describes the cycle). That does not show up in the free-recoil arithmetic at all.
• The rifle is heavy, deliberately. A heavy-profile barrel (2.5 lb by itself on Bear Creek’s listing for its current 16-inch .450 barrel) and a 3-15×50 scope are recoil-reduction components whether or not they were chosen as such.
• The stock is doing work. The Luth-AR MBA-3 with a 3-axis soft 35-durometer recoil pad is a substantial pad on an adjustable stock, and its adjustable comb matters more here than on a light-recoiling rifle because a scope this size on a flat-top AR sits high (§5.9).

5.4 Optics

My rifle carries a Vector Optics Paragon 3-15×50 on a 30 mm tube, on a Primary Arms offset mount, as recorded in my inventory in September 2026. Optics move between rifles in this collection, so that is the configuration as recorded, not a permanent fixture. Optic theory belongs to the Scopes dive.

The important number is the bottom of the magnification range, not the top. On a cartridge whose useful life ends at about 200 yards, 3× is the setting that matters. A deer at 80 yards in Michigan cover is a 3× or 4× proposition; 15× is for checking groups off a bench.

• A genuinely low bottom end. A 1-6×, 2-7× or 3-9× is the natural fit for a 200-yard big bore, and a wide field of view at the low end is worth more than resolution at the top.
• Eye relief matters more than on a .223. At 18 ft-lbf in a rifle that sits high, generous and consistent eye relief is a safety feature.
• Elevation travel is a non-issue. A cartridge that is 5.1 inches low at 200 yards off a 150-yard zero does not need a tall turret. It does not reach far enough to need dialling.
• A simple duplex or a lightly holdover-marked reticle is sufficient, because §5.1 established the correct hold across the whole useful range is dead on.

⚠ The offset mount’s purpose is not clear from the record. An offset mount normally carries a secondary sight, commonly a red dot for close shots. My inventory lists an offset mount for this rifle but records no secondary optic on it, so what is mounted where is not stated here.

5.5 Practical accuracy: the honest position

No measured accuracy data for this rifle exists, and none is manufactured here.

What can be said about the configuration, as mechanism rather than measurement:

• The heavy-profile barrel suits a rifle shot from a bipod and zeroed carefully.
• The RISE Armament RAVE 140 drop-in trigger is a meaningful accuracy component. A good trigger is worth more on a hunting rifle than most barrel upgrades.
• The 1:24 twist stabilises the supersonic factory loads with a wide margin; the cartridge dive’s Volume 4 computes a Miller stability factor of about 4 for the two Federal supersonic bullets whose length is published, against a working minimum of about 1.4. It is the heavy subsonic bullets for which 1:24 is marginal (Volume 2 §2.4).
• The bipod and adjustable-comb stock will produce repeatable results if the shooter does.

⚠ Published accuracy expectations for the .450 Bushmaster could not be verified from any controlled source. Figures around 1.5 to 2 MOA circulate for factory ammunition in AR-pattern rifles; none of the sources examined documented a test protocol, a sample size or a rifle. No accuracy figure is asserted here.

Accuracy is not this cartridge’s binding constraint. At 200 yards even 2 MOA is a 4-inch group, comfortably inside the vital zone. The cartridge runs out of trajectory, wind tolerance and, for the Federal Fusion, the maker’s own expansion floor, long before it runs out of precision.

5.6 The measurement nobody has made

Every velocity figure in this dive is a maker’s number from a barrel that is not this rifle’s barrel. Hornady’s 2,200 fps is from 20 inches. SAAMI’s 2,250 fps is from 24 inches. My barrel is 16 inches, shorter than both, so every velocity quoted here is an upper bound for it, not an estimate that might fall either way.

No maker publishes a velocity loss per inch for supersonic .450 Bushmaster, and none is printed here; the cartridge dive’s Volume 4 records the only barrel-to-barrel figures that exist and why they do not settle it. (Tromix publishes 25 fps per inch for the .458 SOCOM down to 10.5 inches; that is a different cartridge and the figure is not transferred.)

What the uncertainty does to the answers, with the model:

Table 9 — What the uncertainty does to the answers, with the model

Muzzle velocity	Energy at 100 yd	Energy at 200 yd	Path at 200 yd, 150-yd zero	Path at 100 yd, 150-yd zero
2,200 fps (Hornady, 20 in)	1,861 ft-lbf	1,268 ft-lbf	−5.1”	+2.0”
2,100 fps	1,687 ft-lbf	1,148 ft-lbf	−5.7”	+2.2”
2,000 fps	1,523 ft-lbf	1,037 ft-lbf	−6.3”	+2.5”

⭐ The trajectory barely cares. A 200 fps error moves the 200-yard impact by 1.2 inches, irrelevant against an 8-inch vital zone. A hunter can zero at 150 and hold dead on to about 190 yards without knowing the muzzle velocity at all.

The terminal end does care. Federal publishes a minimum expansion velocity of 1,400 fps for its 260 gr Fusion; from Federal’s own muzzle velocity it reaches that at about 206 yards, and 100 fps of lost velocity pulls the crossing in to about 183 (the cartridge dive’s Volumes 3 and 4). Hornady publishes no floor for the FTX my rifle is set up for, so no FTX crossing is given.

5.7 Hunting use

Zero at 150 (or 175) and forget about holdover. §5.1 is the whole of the field procedure.

Treat 200 yards as the limit and mean it. Three independent limits arrive there together: the 8-inch point-blank range (§5.1), the wind (§5.7), and, for the one supersonic bullet whose maker publishes it, the expansion floor (§5.5).

🔴 Check the magazine against the six-round rule. Michigan prohibits taking an animal with, or possessing in an area frequented by animals, a semi-automatic rifle “capable of holding more than six shells at one time in the magazine and barrel combined” (Volume 3 §3.4). My four-round Lancer magazines comply with one chambered; a larger .450 magazine body does not. The test is what the rifle can hold, not what is loaded.

The fast second shot is a real advantage and a real temptation. A semi-automatic big bore offers a follow-up a slug gun or a single shot does not. It is not a licence to take the first shot less carefully.

The cartridge suits the terrain it was bought for. Southern Michigan deer hunting is largely woodlot, field-edge and blind shooting well inside 200 yards. The legal reason for the cartridge has gone (Volume 3); the terrain reason has not.

5.8 Wind, and the number nobody mentions

Trajectory gets the attention and wind is the larger practical problem. For a full-value 10 mph crosswind, same model:

Table 10 — Trajectory gets the attention and wind is the larger practical problem. For a full-value 10 mph crosswind, same model

Range	Time of flight	Drift, 10 mph
50 yd	0.071 s	0.6”
100 yd	0.150 s	2.3”
150 yd	0.236 s	5.5”
200 yd	0.330 s	10.1”
250 yd	0.434 s	16.5”
300 yd	0.549 s	24.6”

🔴 Ten inches of drift at 200 yards is more than the vital zone is wide. Against cartridges a hunter is likely to have a feel for, all at 200 yards in the same wind:

Table 11 — 🔴 Ten inches of drift at 200 yards is more than the vital zone is wide. Against cartridges a hunter is likely to have a feel for, all at 200 yards in the same wind

Cartridge	Drift at 200 yd
.308 Winchester, 150 gr	3.5”
.223 Remington, 55 gr	5.1”
.450 Bushmaster, 250 gr FTX	10.1”

⭐ The .450 Bushmaster drifts roughly three times as much as a .308 and twice as much as a .223. That is the price of a ballistic coefficient of .21: drift grows with how far the bullet lags behind where it would be in a vacuum, and a blunt bullet losing speed fast lags a long way.

The makers’ own drift figures say the same across the field. Federal and Remington publish 10 mph drift at 200 yards of 11.3 to 15.9 inches for their .450 loads, worse than the FTX (cartridge dive Volume 5). Inside 100 yards a 10 mph wind moves the FTX 2.3 inches and can be ignored on a deer; between 100 and 200 it is a hold that has to be judged; past 200 it is the largest single source of a miss.

5.9 Temperature, and a problem this cartridge does not have

Supersonic bullets slowing toward the speed of sound can become unpredictable in the transonic region, and cold air lowers the speed of sound.

The supersonic .450 Bushmaster loads never get near it. The speed of sound runs from about 1,062 fps at 10 °F to 1,139 fps at 80 °F. The FTX is still doing 1,252 fps at 300 yards, supersonic across every temperature a Michigan November produces and far beyond any distance the cartridge should be used at.

The subsonic loads are a different case: Hornady’s 395 gr Sub-X starts at 1,050 fps from 20 inches and is subsonic by design. Whether it stabilises in a 1:24 barrel is an open question for this rifle (Volume 2 §2.4; owner question 4).

⚠ Temperature still affects muzzle velocity through propellant temperature sensitivity, and no temperature-sensitivity data for any .450 Bushmaster factory load was located. A rifle zeroed in August may not shoot to exactly the same point in December; the only way to know is to check it.

5.10 Mounting the optic, and why sight height matters here

An AR-15 puts the line of sight well above the bore: the flat-top rail sits high, and a 50 mm objective in 30 mm rings higher still.

The cheek weld has to come up to meet the scope. That is what the MBA-3’s adjustable cheek riser is for, and on a rifle with a 3-15×50 it is not a luxury. Inconsistent eye position on a rifle with 18 ft-lbf of recoil is how people get hit by scopes.

Sight height changes the near trajectory, and this volume’s own correction (§5.0) is the proof. The tables in §5.1 use 1.5 inches, the figure Federal and Remington assume. Hornady’s own table for this load assumes 2.4 inches, which is more typical of an AR-15 with a scope in rings, and the corrected solver reproduces Hornady’s printed table only with that figure. The height of the scope on my rifle has not been measured. At 2.4 inches the numbers move a little:

Table 12 — Sight height changes the near trajectory, and this volume's own correction (§5.0) is the proof. The tables in §5.1 use 1.5 inches, the figure Federal and Remington assume. Hornady's own table for this load assumes 2.4 inches, which is more typical of an AR-15 with a scope in rings, and the corrected solver reproduces Hornady's printed table only with that figure. The height of the scope on my rifle has not been measured. At 2.4 inches the numbers move a little

150-yd zero	25 yd	100 yd	200 yd	Stays in an 8 in zone to
1.5 in sight height	+0.2”	+2.0”	−5.1”	about 191 yd
2.4 in sight height	−0.6”	+1.7”	−4.8”	about 193 yd

The recommendation does not change. What changes is the 100-yard hold that sets it (§5.10), and the close-range path: with a tall mount the bullet is still below the line of sight at 25 yards, which matters for a shot through a gap in cover at close range.

The bipod and the bench are not the field. A Harris bipod on an M-LOK rail is the right tool for zeroing and for a blind with a rail. Most shots at deer are not taken from it.

5.11 A zero procedure that suits this cartridge

Ammunition at $2.00 to $3.95 a round on the makers’ own October 2026 list prices (Volume 6 §6.3) rewards a deliberate process.

1. Bore-sight first. Remove the bolt carrier group (Volume 8 §8.1) and look through the barrel at a target at 50 yards. It costs nothing and saves a box.
2. Start at 25 yards and get on paper.
3. Move to 100 yards and set the group 2.0 inches high (1.5-inch sight height) or 1.7 inches high (2.4-inch sight height). From §5.1 and §5.9, a rifle that high at 100 is zeroed at 150. For a 175-yard zero the hold at 100 is 3.2 inches (2.8 with the taller mount). This lets the 150 or 175-yard zero be set on a 100-yard range.
4. Confirm at 150 or 200 if a range allows it. The model inherits Hornady’s 20-inch velocity, and a 16-inch barrel will drop a little more than the table shows.
5. Shoot the confirmation group from a cold barrel, in the position and with the load intended for hunting.
6. Write the zero down: range, load, barrel length, temperature, date.

⚠ This step replaces the version first published on 17 September 2026, which said 2.5 inches high; on the corrected model that zeroes the rifle at about 160 yards (§5.0).

5.12 References (Vol 5)