The Straight-Wall Laws: Michigan's Rise and Repeal, and the Four Other States

This volume is not legal advice. Every rule below is quoted or summarised from the state’s own statute, administrative rule or wildlife agency page on the date given. Hunting regulations change every season, and two of these five changed within the last eighteen months. Check the current digest before hunting.

7.1 Why a cartridge needed a law

In much of the agricultural Midwest, deer seasons were long restricted to shotguns, a rule usually explained by a slug’s shorter reach in flat, settled country. From 2014, beginning with Michigan, several states began admitting rifles chambered for straight-walled cartridges, a category that in practice meant big, slow, pistol-like rounds with short reach. Each state drew the line differently: by calibre, by case length, by “straight” or “necked.”

The .450 Bushmaster fits almost every such line drawn. It is large in calibre (.4525 inch), straight-walled, short (1.700 inches), and readily available in an AR-15 or a light bolt gun. In Michigan it fitted a case-length window that excluded its obvious rival, the .45-70. That is a large part of why the cartridge sold.

7.2 Michigan: the rule

Michigan’s equipment rules for hunting are set by the Wildlife Conservation Order (WCO), issued by the Natural Resources Commission under Part 401 of the Natural Resources and Environmental Protection Act. Section 2.1 lists what a hunter “shall not” do. Its subsection (4) was the straight-wall rule, applying in the “limited firearms deer zone,” the southern Lower Peninsula below a line defined by highways and county lines in Chapter I of the order.

The text of subsection (4), as posted before the repeal and quoted from michigan.gov in the AR-15 dive on 17 September 2026, admitted in the zone, among other firearms:¹

“(d) A .35 caliber or larger rifle loaded with straight-walled cartridges with a minimum case length of 1.16 inches and a maximum case length of 1.80 inches.”

The .450 Bushmaster passes all three tests (.4525 inch, straight, 1.700 inches) with a tenth of an inch to spare at the top of the window. The .45-70 Government, at 2.105 inches, fails the length test. ⭐ The 1.80-inch ceiling is the one-line reason a Michigan hunter in the southern zone bought a .450 Bushmaster rather than a .45-70.

When the rule came in. The WCO’s history line for section 2.1 records “Am. 6, 2014, Eff. June 13, 2014” among its amendments,² and contemporary accounts date the Commission’s adoption of straight-walled rifles in the then “shotgun zone” to June 2014, with a three-year sunset later removed. The amendment document itself was not read for this dive, so the 2014 date is given from the order’s own history line and the sunset from secondary accounts.³ The AR-15 dive’s Volume 3 quotes the zone’s geographic definition in full.

7.3 Michigan: the repeal, in the order’s own text

The Natural Resources Commission approved the change on 15 May 2026. Its news release lists, among the 2026 changes:⁴

“Elimination of the Limited Firearms Deer Zone in the Lower Peninsula, allowing the use of all legal firearms, including bottleneck cartridges, throughout the Lower Peninsula. Firearms larger than .22 rimfire are now permitted statewide.”

The DNR’s bulletin “2026 deer hunting regulations – what’s new,” sent on 19 August 2026, puts it as:⁵

“The Limited Firearms Deer Zone has been eliminated. Beginning Sept. 12, hunters may use all legal firearms across the Lower Peninsula.”

And the order itself, as posted on 19 October 2026, now reads at section 2.1(4):²

“(4) Repealed; Am. 6, 2026, Eff. May 24, 2026. Publishers Note: The repealed section pertained to legal firearms allowed for use to take deer in the ‘limited firearms deer zone.’ The limited firearms deer zone was repealed effective September 12, 2026.”

Chapter I carries the matching entry where the zone’s definition used to be: “(17) Repealed; Am. 6, 2026, Eff. May 24, 2026,” with the same publisher’s note.⁶

⚠ A correction to the AR-15 dive. Its Volume 3, §3.3 records that on 17 September 2026 the posted WCO chapters “still contain the old rule,” that no 2026 deer-firearms amendment document could be found, and treats the conflict as a documentation lag. The lag has closed. As posted on 19 October 2026, both chapters carry the repeal and name it: Wildlife Conservation Amendment No. 6 of 2026, effective 24 May 2026, with the zone repealed effective 12 September 2026. The dive’s reading was right; the documents now agree with it.

Two dates are worth keeping distinct. The amendment took effect on 24 May 2026; the zone ended on 12 September 2026, the opening of the early antlerless and Liberty Hunt seasons, so that no season was changed after it had started.

So, in Michigan from 12 September 2026, a .450 Bushmaster is simply a rifle larger than .22 rimfire, legal for deer across the state like a .308 or a .30-06. Its legal advantage is gone. Its ballistic character is unchanged.

7.4 Michigan: what still binds a .450 rifle

The repeal removed one restriction. These remain in the order as posted on 19 October 2026:²

The semi-automatic capacity rule, section 2.1(2):

“Use in taking an animal, or have in the persons possession in an area frequented by animals, a semiautomatic shotgun or rifle other than .22 caliber or smaller rimfire, capable of holding more than six shells at one time in the magazine and barrel combined …”

The test is what the rifle is capable of holding, not what is loaded, and it applies to possession in an area frequented by animals, not only to shooting. A .450 Bushmaster AR-15 with a four-round magazine holds five and complies; the same rifle with a magazine that holds six or more does not, even if it is loaded with three. The AR-15 dive’s Volume 4 works this through for that rifle’s magazines.

The quiet period, section 2.1(3): “During the five days immediately preceding November 15, transport or possess in an area frequented by deer a rifle or shotgun with buckshot, slug load, ball load, or cut shell,” with an exception for transport to and from camp unloaded and cased.

Transport, legal hours and the December season are covered from the DNR digest in the AR-15 dive’s Volume 3 and are not repeated. One 2026 change from the same package is worth adding because it widens where the rifle can be used: the DNR bulletin confirms that the December firearm season in the Lower Peninsula now runs 4 to 6 December and that “hunters may use all legal firearms during the December season.”⁵

Suppressors. Hunting with a lawfully owned suppressor is legal in Michigan; the federal and state position, including the $0 federal tax from 1 January 2026, is in Suppressor Law, Volume 7.

7.5 Ohio

Ohio Administrative Code 1501:31-15-11, “Deer hunting,” effective 6 July 2026:⁷

“(iv) A rifle with the following criteria: Chambered for a straight-walled cartridge with a minimum caliber of .357 to a maximum caliber of .515.”

“(b) It shall be unlawful for any person hunting deer to use in any rifle or possess any rifle cartridge which is necked down.”

“(c) It shall be unlawful for any person hunting deer during any deer gun season, to possess or use any shotgun or rifle which is loaded with more than three shells or cartridges in the magazine and chamber combined.”

Ohio is still a straight-wall state, and its rule is cleaner than Michigan’s was: a calibre window of .357 to .515 with no case-length limit, and a flat ban on necked-down rifle cartridges. The .450 Bushmaster passes; so does the .45-70, which Michigan’s old rule excluded. The rule also bars possessing rifle cartridges during the muzzleloader season.

The AR-15’s constraint in Ohio is three loaded rounds in magazine and chamber combined. Unlike Michigan’s, Ohio’s test is what is loaded, not what the rifle could hold: a rifle with a larger magazine is legal if it carries no more than three. Handguns must be straight-walled, .357 magnum or larger, with a barrel of at least five inches.

7.6 Indiana

Indiana dropped its straight-wall rule in 2025. The Indiana DNR’s deer-equipment page, read 19 October 2026, gives the rifle rule as:⁸

“Centerfire rifles with a bullet diameter of at least .219 inches or 5.56 mm. Full-metal jacketed bullets are illegal. Hunters may carry no more than 10 of each cartridge type at a time. May be used on both public and private land.”

The DNR’s rule-change notice explains why: the amendment to 312 IAC 9-3-3(d) was “needed to comply with IC 14-22-2-8 by removing the minimum bullet diameter and cartridge length specifications. During the 2025 legislative session, the Indiana General Assembly passed SEA 280 (P.L.76-2025), which sets forth the requirements for rifles used for deer hunting and prohibits the department from placing additional restrictions on rifles.”⁹

So in Indiana, as in Michigan, the .450 Bushmaster is now just one legal rifle cartridge among many. Indiana’s earlier rifle rules carried case-length windows that are not reproduced here, because the earlier statute text could not be read from a primary source. The same page states that suppressors are legal for deer hunting “as long as the hunter is in compliance with federal law,” and that full-metal-jacket bullets are illegal, which rules out the Federal and Remington FMJ loads in Volume 3 for hunting.

7.7 Iowa

Iowa’s rifle rule is set by Iowa Code §481A.48 (the 2026 Code) and the Iowa DNR’s rules. The statute directs the commission to allow cartridge rifles in the youth and disabled season and the first and second shotgun seasons, using the same ammunition allowed in handguns: “straight wall or other centerfire ammunition propelling an expanding-type bullet with a maximum diameter of no less than three hundred fifty thousandths of one inch and no larger than five hundred thousandths of one inch and with a published or calculated muzzle energy of five hundred foot pounds or higher.” A person possessing a prohibited rifle while hunting deer has hunting privileges suspended for two years.¹⁰

The DNR’s deer page states the current rule plainly:¹¹

“Straight-wall and ‘necked-down’ cartridge rifles shooting an expanding type bullet of at least .350 inches and no greater than .500 inches with at least 500 foot pounds of muzzle energy.”

It names the .450 Bushmaster among the qualifying calibres, says that “.350 and .500 are legal … If it’s .349 or less or .501 or more, it’s not legal,” and answers a question that matters for an AR-15: “No, there is not a maximum round count for rifle or shotgun magazines for deer hunting in Iowa.”

⭐ Iowa is no longer a straight-wall state in the strict sense. It is a bore-size window state: anything from .350 to .500 inch with an expanding bullet and 500 ft-lbf qualifies, necked or not. The statute’s history line lists amendments in 2017, 2020 and 2022.¹⁰ The .450 Bushmaster qualifies with its expanding loads. So does the 395-grain Sub-X (967 ft-lbf at the muzzle on Hornady’s figure), which matters for a hunter who wants to hunt suppressed.

7.8 Illinois

Illinois came to rifles late and is still changing. Section 2.25 of the Wildlife Code (520 ILCS 5/2.25):

2023 to 2026 seasons. Public Act 102-0932, effective 1 January 2023, admitted single-shot centerfire rifles.¹² The text in force for 2026, as amended by Public Act 104-0058 (effective 1 January 2026), reads:¹³

“The only legal ammunition for a centerfire handgun or rifle is a bottleneck centerfire cartridge of .30 caliber or larger with a case length not exceeding one and two-fifths inches, or a straight-walled centerfire cartridge of .30 caliber or larger, both of which must be available as a factory load with the published ballistic tables of the manufacturer showing a capability of at least 500 foot pounds of energy at the muzzle.”

The IDNR’s own explanation of “single shot” closes the AR-15 question: a rifle counts as single shot only “if there is no magazine in possession of or in close proximity to a hunter in the field and the gun can only hold a total of one round.”¹²

From 1 January 2027. Public Act 104-0627 (SB 2756) strikes “single shot” and substitutes rifles “capable of holding not more than 3 rounds in the magazine and chamber combined. If a centerfire handgun or centerfire rifle is capable of holding more than 3 rounds, it shall be fitted with a one-piece plug that is irremovable without dismantling the handgun or rifle or it shall be otherwise altered to render it incapable of holding more than 3 rounds.”¹⁴ The IDNR confirms the change and that “Single shot restrictions will still apply to all applicable firearm deer seasons prior to Jan. 1, 2027.”¹²

⚠ An open question, not answered by any source read. The plug language is written for fixed and tube magazines. How a rifle that accepts detachable box magazines, such as an AR-15 or a Ruger American, satisfies “capable of holding not more than 3 rounds” (a permanently limited magazine, a modified magazine well, or something else) is not addressed in the act or the IDNR’s notice. A hunter planning to use one in Illinois from 2027 should ask the IDNR.

Illinois’s ammunition test is also unusual in naming the manufacturer’s published ballistic tables as the evidence of 500 ft-lbf. Every .450 Bushmaster hunting load in Volume 3 passes it on its maker’s page, except Winchester’s, whose pages currently publish no ballistics at all.

7.9 The pattern

Set side by side, the five states show a clear direction:

Table 1 — Set side by side, the five states show a clear direction

State	2014 to 2024	October 2026
Michigan	straight-wall, .35+, 1.16–1.80 in, southern zone	any rifle above .22 rimfire
Indiana	rifle cartridges restricted by bore and case length	any centrefire .219+ (2025)
Iowa	straight-walled pistol cartridges in rifles (2017)	.350–.500, straight or necked
Ohio	straight-walled rifles (start date not confirmed here)	straight-walled .357–.515, 3 loaded
Illinois	none, then single-shot straight-wall or short bottleneck (2023)	single shot; 3 rounds from 2027

Every change since 2023 has loosened the rule, and two states have dropped the straight-wall test altogether. For the .450 Bushmaster that is a loss of its legal niche in the two states that dropped it, and no loss anywhere else: it qualifies in every state on the list. So, now, does the .45-70 Government, which Michigan’s case-length window used to exclude; the .450’s specific legal edge over its big-bore rival has gone everywhere except in its fit to an AR-15.

7.10 The stale-copy problem

Regulations change faster than the writing about them. On 19 October 2026, five weeks after Michigan’s zone ended, an ammunition maker’s product pages still described two of its .450 loads as “legal for most parts of shotgun-only zones in Michigan, Indiana, Ohio”; in October 2026 that is true of Ohio alone.¹⁵ It is not the maker’s fault that the law moved; it is a fair example of why every legal statement in this volume carries the date it was read, and why the hub’s earlier .450 dive, written five days after the repeal took effect, already needed one of its sections updated.

References

Footnotes

1. Wildlife Conservation Order, Chapter II §2.1(4), text as posted at michigan.gov before the repeal, quoted in the hub’s .450 Bushmaster AR-15 dive, Volume 3, read there 17 September 2026. The repealed text is no longer posted. ↩

2. Michigan Department of Natural Resources, Wildlife Conservation Order, Chapter II, General Hunting and Trapping Regulations, michigan.gov (ChapterII.pdf), as posted 19 October 2026: §2.1(2), (3) and (4) and the section’s history line. URLs: https://www.michigan.gov/dnr/-/media/Project/Websites/dnr/Documents/Orders/Wildlife-Conservation-Order/ChapterII.pdf?rev=810e1d59cbb3490189dab4ab4e983b00&hash=DFF23E219D6455BE35FAB7893F64604C; https://www.michigan.gov/dnr/managing-resources/laws/orders/wildlife-conservation-order. ↩ ↩² ↩³

3. The June 2014 adoption and three-year sunset are as reported by Michigan United Conservation Clubs and contemporary accounts; the 2014 amendment document was not read. The order’s own history line records Am. 6 of 2014, effective 13 June 2014. ↩

4. Michigan DNR, news release “NRC approves deer regulation changes for 2026 and 2027,” 15 May 2026, michigan.gov/dnr, read 19 October 2026. URL: https://www.michigan.gov/dnr/about/newsroom/releases/2026/05/15/nrc-approves-deer-regulation-changes-for-2026-and-2027. ↩

5. Michigan DNR, bulletin “2026 deer hunting regulations – what’s new,” sent 19 August 2026 (content.govdelivery.com/accounts/MIDNR/bulletins/4250286), read 19 October 2026. URL: https://content.govdelivery.com/accounts/MIDNR/bulletins/4250286. ↩ ↩²

6. Michigan DNR, Wildlife Conservation Order, Chapter I, Title and Definitions, michigan.gov (ChapterI.pdf), as posted 19 October 2026: §1.2(17). URL: https://www.michigan.gov/dnr/-/media/Project/Websites/dnr/Documents/Orders/Wildlife-Conservation-Order/ChapterI.pdf?rev=e55c6a213cc447619393f86fe45e08ea&hash=F540715B3A12A575E68AB314699A3BD8. ↩

7. Ohio Administrative Code 1501:31-15-11, “Deer hunting,” effective 6 July 2026, codes.ohio.gov, read 19 October 2026: paragraphs (C)(2)(a)(iii)–(iv) and (b), (c), (f). URL: https://codes.ohio.gov/ohio-administrative-code/rule-1501:31-15-11. ↩

8. Indiana DNR, “Deer Hunting Equipment,” in.gov/dnr/fish-and-wildlife/hunting-and-trapping/deer-hunting/deer-hunting-equipment, read 19 October 2026. URL: https://www.in.gov/dnr/fish-and-wildlife/hunting-and-trapping/deer-hunting/deer-hunting-equipment. ↩

9. Indiana DNR, “Rule & Regulation Changes,” in.gov/dnr/fish-and-wildlife/rule-regulation-changes, read 19 October 2026: entry for 312 IAC 9-3-3. URL: https://www.in.gov/dnr/fish-and-wildlife/rule-regulation-changes. ↩

10. Iowa Code §481A.48 (Iowa Code 2026), legis.iowa.gov/docs/code/481A.48.pdf, read 19 October 2026: subsections 5 and 6 and history line. URL: https://www.legis.iowa.gov/docs/code/481A.48.pdf. ↩ ↩²

11. Iowa DNR, “Deer Hunting,” iowadnr.gov/deer, read 19 October 2026: legal firearms for the youth/disabled and shotgun seasons, and FAQ. URL: https://www.iowadnr.gov/deer. ↩

12. Illinois DNR, “Single-shot rifles and deer hunting in Illinois — Frequently asked questions,” dnr.illinois.gov/hunting/law-change-that-affects-hunting-season.html, read 19 October 2026. URL: https://dnr.illinois.gov/hunting/law-change-that-affects-hunting-season.html. ↩ ↩² ↩³

13. Illinois General Assembly, Public Act 104-0058 (HB 2339), effective 1 January 2026, ilga.gov, read 19 October 2026: 520 ILCS 5/2.25. URL: https://ilga.gov/legislation/PublicActs/View/104-0058. ↩

14. Illinois General Assembly, Public Act 104-0627 (SB 2756), effective 1 January 2027, ilga.gov, read 19 October 2026: 520 ILCS 5/2.25 as amended (inserted and struck text). URL: https://ilga.gov/legislation/PublicActs/View/104-0627. ↩

15. Steinel Ammunition, steinelammo.com, product pages for the 250 gr and 425 gr solid copper hollow point .450 Bushmaster loads, read 19 October 2026. URLs: https://steinelammo.com/all-available-calibers/rifle-ammo/450-bushmaster/450-bushmaster-250gr-maker-solid-copper-hollow-point-schp/; https://steinelammo.com/all-available-calibers/rifle-ammo/450-bushmaster/450-bushmaster-425gr-subsonic-solid-copper-hollow-point-schp/. ↩