They changed the rules. Magnified optics are now allowed.
https://wildlife.utah.gov/rules-regulations/942-r657-5--taking-big-game.html
R657-5-10. Muzzleloaders.
(1) A muzzleloader may be used during any big game hunt, except an archery hunt, provided the muzzleloader:
(a) can be loaded only from the muzzle;
(b) has open sights, peep sights, or a variable or fixed power scope, including a magnifying scope;
(c) has a single barrel;
(d) has a minimum barrel length of 18 inches;
(e) is capable of being fired only once without reloading;
(f) powder and bullet, or powder, sabot and bullet are not bonded together as one unit for loading;
(g) is loaded with black powder or black powder substitute, which must not contain smokeless powder.
(2)(a) A lead or expanding bullet or projectile of at least 40 caliber must be used to hunt big game.
(b) A bullet 130 grains or heavier, or a sabot 170 grains or heavier, must be used for taking deer and pronghorn.
(c) A 210 grain or heavier bullet must be used for taking elk, moose, bison, bighorn sheep, and Rocky Mountain goat, except sabot bullets used for taking these species must be a minimum of 240 grains.
(3)(a) A person who has obtained a muzzleloader permit for a big game hunt may:
(i) use only muzzleloader equipment authorized in this Subsections (1) and (2) to take the species authorized in the permit; and
(ii) not possess or be in control of a rifle or shotgun while in the field during the muzzleloader hunt.
(b) "Field" for purposes of this section, means a location where the permitted species of wildlife is likely to be found, but does not include a hunter's established campsite or the interior of a fully enclosed automobile or truck.
(c) The provisions of Subsection (a) do not apply to:
(i) a person lawfully hunting upland game or waterfowl;
(ii) a person licensed to hunt big game species during hunts that coincide with the muzzleloader hunt;
(iii) livestock owners protecting their livestock; or
(iv) a person licensed to carry a concealed weapon in accordance with Title 53, Chapter 5, Part 7 of the Utah Code, provided the person is not utilizing the concealed firearm to hunt or take protected wildlife.
(4) A person who has obtained an any weapon permit for a big game hunt may use muzzleloader equipment authorized in this Section to take the species authorized in the permit.