Check the DFW regs......Pretty clear you can Not use a scope on a muzzle loader unless you're almost blind.
.•(h) Under the provisions of a muzzleloading rifle only tag, hunters may only possess muzzleloading rifles as described in subsection 353(a) equipped with open or "peep" type sights only except as describled in subsection 353(k).
•(i) Under the provisions of a muzzleloading rifle/archery tag, hunters may only possess muzzleloading rifles with sights as described in subsection 353(f); archery equipment as described in Section 354; or both. For purposes of this subsection, archery equipment does not include crossbows, except as provided in subsection 354(j).
(1) Applications for a Disabled Muzzleloader Scope Permit,as specified in Section 702 of these regulations shall be submitted to the department at the address specified on the application and shall include:
(A) Applicant's name
(B) Applicant's physical address
(C) Applicant's date of birth
(D) Applicant's Driver's License or DMV Number
(E) Applicant's telephone number
(F) Applicant's signature
(G) Medical Physician's or Optometrist’s name
(H) Medical Physician's or Optometrist’s business address
(I) Medical Physician's or Optometrist’s business telephone number
(J) Medical Physician's State medical license number or Optometrist’s State license number
(K) A description of the visual disability requiring this permit
(L) Medical Physician's or Optometrist’s signature
(M) Signature of the authorizing department employee and date issued
◦ (2) The applicant must have a valid hunting license for the year for which he/she is applying.
◦ (3) Proof of meeting eligibility requirements may be met by providing a previously issued Disabled Muzzleloader Scope Permit.
◦ (4) The valid Disabled Muzzleloader Scope Permit shall be in the hunter’s immediate possession while hunting and shall be shown on demand to any person authorized to enforce this regulation.
◦ (5) The Disabled Muzzleloader Scope Permit is valid from July 1 through June 30 of the following year or if issued after July 1 of the license year, it is valid beginning on the date issued through to the following June 30.
• (m) For the purposes of this section a visual disability means a permanent loss, significant limitation, or diagnosed disease or disorder, which substantially impairs the vision of a hunter, preventing the hunter from viewing and aligning the sights of a muzzleloading rifle with the target in order to hunt deer