Owning One — Brass, Cost, and the Alternatives Now That the Rule Is Gone

Volume 3 removed the .450 Bushmaster’s legal argument in Michigan. This volume asks what is left, and the answer is more favourable than the framing suggests, but not unconditional.

⚠ Update, 19 October 2026. Maintenance (§6.1) now has its own volume, Volume 8. Starline’s brass, unconfirmed in the first edition, is now confirmed on Starline’s own page (§6.2). The ammunition prices in §6.3 are re-read from the makers’ pages on 19 October 2026; Federal’s had fallen.

6.1 Maintenance, in brief

The action is an ordinary AR-15 and is cleaned and lubricated like one. Volume 8 sets out only what differs for the .450, from the Army’s armorer manual and the big-bore makers’ own guidance. The three things worth remembering here:

• The bolt, extractor and ejector are big-bore parts and the bolt belongs with its barrel; never swap carrier groups between a .450 and a 5.56 rifle (Volume 8 §8.1).
• The chamber step is the headspace datum, so carbon there matters more than on a 5.56 (Volume 8 §8.3).
• For a hunting rifle the risk is corrosion, not wear. The parkerized barrel and nitride carrier on my rifle help; they are not a substitute for wiping it down after a wet day (Volume 8 §8.7).

6.2 Brass and reloading

The .450 Bushmaster is a good handloading proposition, chiefly because the bullet is a .452, the diameter of the .45 Colt, .45 ACP, .454 Casull and .460 S&W, which is the deepest large-diameter bullet pool in North America.

Brass is confirmed on its maker’s page. Starline lists #3220, 450 Bushmaster brass, “1.693 - 1.697 O.A.L. Small Rifle Primer”, at $0.84 each in a box of 250 ($210.00), $0.77 at 500 and $0.74 at 1,000, “Available Now”, on 19 October 2026.¹ The first edition could not read Starline’s page and rested on a secondary source; it also said the SAAMI drawing does not specify a primer size, which is still true of the drawing, but the maker’s listing settles it: small rifle. The case length, 1.693 to 1.697, sits inside SAAMI’s 1.700 −.010.

Loading it is a separate dive, Loading the .450 Bushmaster, and the taper-and-carbide point is The Reloading Bench, Volume 12. Three facts bear on the rifle and are repeated here only as pointers:

• Case length is headspace on this cartridge (Volume 2 §2.2); over-trimmed brass headspaces long.
• The magazine, not the chamber, sets the longest cartridge that will feed (Loading the .450 Bushmaster, Volume 4).
• Rounds chambered repeatedly in an autoloader can set back; retire them from the magazine.

This dive publishes no load data.

6.3 What it costs to feed

Makers’ own listed prices for a box of 20, read 19 October 2026 (first-edition prices of 17 September in brackets where they differ):²

Table 1 — 6.3 What it costs to feed

Load	Price / 20	Per round
Federal American Eagle 260 gr FMJ	$39.99 (was $41.99)	$2.00
Remington UMC 260 gr FMJ	$39.99 (was $41.99)	$2.00
Steinel 240 gr JHP	$51.19	$2.56
Steinel 425 gr subsonic SCHP	$66.34	$3.32
Federal Power-Shok 300 gr	$68.99 (was $71.99)	$3.45
Remington Core-Lokt 260 gr	$69.99	$3.50
Remington Premier AccuTip 260 gr	$69.99	$3.50
Steinel 280 gr brass solid	$70.58	$3.53
Federal Fusion 260 gr	$76.99 (was $79.99)	$3.85
Steinel 250 gr SCHP	$78.99	$3.95
Hornady (four loads), Winchester (two)	not shown on the makers’ pages

⚠ The first edition gave Remington UMC at $41.99; the cartridge dive read $39.99 in October. These are list prices, not street prices; retailers routinely sell below them.

My own record has the Hornady 250 gr FTX, the load my rifle is set up for, at a local shelf price of $39.99 a box, $2.00 a round. That is my note from my inventory; its date is not recorded, and Hornady’s own page shows no price.

Two conclusions:

• Practice ammunition exists and is affordable by big-bore standards. Full metal jacket at $2.00 a round makes it possible to shoot the rifle rather than only zero it.
• It is still several times the cost of .223. A realistic annual budget for a hunting rifle is a box to confirm zero and a box or two of practice.

Availability no longer depends on one company: Hornady, Federal, Remington and Winchester, with Steinel, catalogue the cartridge, and none of them is the company it is named after (Volume 1 §1.3).

6.4 The alternatives, honestly

Muzzle energies are computed from the makers’ published bullet weights and velocities; free recoil per Volume 5 §5.2.

Table 2 — 6.4 The alternatives, honestly

Cartridge / load	Muzzle energy	Free recoil	Platform
.350 Legend, 160 gr Fusion	1,880 ft-lbf	lowest here	AR-15 (5.56 bolt)
.350 Legend, 180 gr	1,763 ft-lbf		AR-15
.400 Legend, 215 gr Power Point	2,417 ft-lbf		AR-15 (own bolt)
.450 Bushmaster, 250 gr FTX	2,687 ft-lbf	18.0 ft-lbf	AR-15 (.450/.458 bolt)
.450 Bushmaster, 300 gr Power-Shok	2,405 ft-lbf		AR-15
.45-70, 300 gr standard pressure	2,355 ft-lbf	21.8 ft-lbf	lever / single shot
12 ga, 438 gr rifled slug	2,522 ft-lbf	28.3 ft-lbf	shotgun
12 ga, 383 gr rifled slug	2,756 ft-lbf	27.3 ft-lbf	shotgun

6.4.1 .350 Legend

Winchester’s 2019 cartridge for straight-wall deer states, SAAMI-standardised on a 16-inch test barrel. Less recoil, a flatter trajectory, cheaper ammunition, more rounds per magazine, and it uses the 5.56 bolt (Volume 7 §7.2), so a .350 Legend upper drops onto a 5.56 carrier group. It carries about 30 per cent less energy than the .450 from a much smaller bullet.

The honest verdict: for deer inside 200 yards the .350 Legend is sufficient, pleasanter to shoot and cheaper to own. If the choice were being made from scratch today, with Michigan’s zone gone, it would be the more sensible straight-wall pick for most hunters.

6.4.2 .400 Legend

Winchester’s 2023 cartridge, between the other two: 2,417 ft-lbf from a .4005-inch bullet, also on a 16-inch SAAMI test barrel, with a .422 rim that takes neither a 5.56 nor a .450 bolt. As a reason to sell an existing .450 it is not persuasive.

6.4.3 gauge slug

The comparison that matters most historically, because in the old zone the slug gun was what most hunters actually used. The two slug loads in my own equipment record produce 2,522 and 2,756 ft-lbf, comparable to the .450 at the muzzle, and ⭐ recoil about 55 per cent harder: 27 to 28 ft-lbf against 18 (Volume 5 §5.2). They also shed velocity faster and shoot worse trajectories. The .450 beats the slug gun on every axis except cost, and that is untouched by the rule change.

6.4.4 .45-70 Government

Not an AR-15 cartridge: its 2.105-inch case lives in lever actions and single shots, and is exactly why it was never legal in Michigan’s old zone, which capped case length at 1.80 inches (Volume 3 §3.1). It is more versatile, loaded from mild cowboy ammunition to bear loads, and its higher-pressure tiers are platform-specific and dangerous in the wrong rifle. The .45-70 Government dive owns that.

6.4.5 The other big-bore AR cartridges

.458 SOCOM. A rebated bottleneck case with a .458 bullet. ⭐ Its rim is .473, the same as the .450’s, so the two share a bolt (Volume 7 §7.2) and a magazine, and Tromix builds uppers and sells one bolt for both. It takes heavier bullets, up to 600 grains on the usual account, and is the better choice for a suppressed subsonic big bore; its .458 bullets are a smaller, dearer pool than the .452 family. It is not in the SAAMI standard, so its figures are its makers’.

.50 Beowulf. Alexander Arms’ rebated straight case with a .500 bullet, and a .445 rim, matched to the 6.5 Grendel, so it needs a different bolt again. Also not in the SAAMI standard.

In one line: the .450 Bushmaster has the best factory ammunition support, the cheapest components and the mildest recoil of the three, and is the only one with a SAAMI standard; the .458 SOCOM is the most versatile, especially suppressed; the .50 Beowulf hits hardest and is the most proprietary.

6.4.6 And now, the bottleneck cartridges

The comparison that did not exist in Michigan before 12 September 2026. A .308 Winchester gives about 2,649 ft-lbf, essentially the .450’s muzzle energy, with less recoil (13.6 against 18.0 ft-lbf), a far flatter trajectory, about a third of the wind drift at 200 yards (Volume 5 §5.7) and cheaper ammunition. For a hunter with no rifle and no constraint, a .308 is the better general-purpose choice. What the .450 has is a larger hole, an AR-15 platform, and the fact that it is already in the safe.

6.5 6.4a Storage, travel and resale

Storage is unremarkable. A parkerized barrel and a nitride carrier tolerate a safe with a dehumidifier.

Travel out of Michigan needs two checks: the destination’s hunting rules (the cartridge dive’s Volume 7 has Ohio, Indiana, Iowa and Illinois; for a semi-automatic the round count is the usual catch) and its possession and transport law, which this dive does not address for any state.

Resale is the uncertain variable. Part of Michigan’s demand for .450 rifles was created by a rule that no longer exists.

⭐ The rifle is not the cartridge. A .450 AR-15 is a lower plus a calibre-specific upper. If the cartridge became inconvenient, the lower, the regulated and serialised part, carries over unchanged to any other AR-15 chambering, the .350 Legend included. The platform is the hedge.

6.6 The verdict

Keep it, and stop justifying it on the law.

My rifle is a sound build: a 1:24 barrel that suits its supersonic load, an MPI-marked big-bore bolt, a good drop-in trigger, a substantial recoil pad, an adjustable comb, and the part most .450 owners get wrong, the right magazines with the right followers. It is compliant with Michigan’s six-shell rule as configured.

What changed on 12 September 2026 is the argument, not the rifle. Inside 200 yards, on deer, from a blind or a field edge, it does exactly what it did before, with a third less recoil than the slug gun that used to be the alternative.

Four measurements would improve this dive more than any part would, and all four are an afternoon’s work on my own rifle:

1. Chronograph it. Nobody publishes .450 velocity from a 16-inch barrel (Volume 5 §5.5).
2. Shoot a group and keep the target, with the FTX and, if a box is to hand, the Sub-X, which settles whether the 1:24 barrel stabilises the 395-grain bullet (Volume 2 §2.4).
3. Gauge the muzzle thread before anything is screwed on (Volume 4 §4.7b).
4. Strip the upper and write down what is in it: gas block, buffer, port, bolt maker, magazine date codes (Volume 7 §7.6).

6.7 References (Vol 6)

Footnotes

1. Starline Brass, “#3220 - 450 Bushmaster Brass,” starlinebrass.com, read 19 October 2026 by the cartridge dive. URL: https://www.starlinebrass.com/450-bushmaster. ↩

2. Makers’ product pages (Federal, Remington, Steinel, Hornady, Winchester), read 19 October 2026, as tabulated in the cartridge dive’s Volume 8. First-edition prices read 17 September 2026. ↩