Im building ar with a pistol buffer tube on lower and a 11.5 upper the oal is 26.5. Do I have to register it as a pistol?

NO

Read the MCL though

http://www.michigan.gov/documents/msp/FIREARM_LAWS_OF_MICHIGAN_447162_7.pdf

http://www.legislature.mi.gov/documents/publications/firearms.pdf

FIREARMS LAWS OF MICHIGAN — 2013
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(b) Fuses, torpedoes, rockets, or other signal devices essential to promote safety in operation.
(c) Properly packed and marked samples for laboratory examination that do not exceed a net weight of 1/2 pound each and
that do not exceed 20 samples at 1 time in a single vessel, car, or vehicle if the samples are not carried in that part of a vessel,
car, or vehicle that is intended for transporting passengers for hire.

CHAPTER XXXVII
FIREARMS
750.222 Definitions.
Sec. 222. As used in this chapter:
(a) “Alcoholic liquor” means that term as defined in section 105 of the Michigan liquor control code of 1998, 1998 PA 58,
MCL 436.1105.
(b) “Barrel length” means the internal length of a firearm as measured from the face of the closed breech of the firearm when
it is unloaded, to the forward face of the end of the barrel.
(c) “Controlled substance” means a controlled substance or controlled substance analogue as those terms are defined in
section 7104 of the public health code, 1978 PA 368, MCL 333.7104.
(d) “Firearm” means a weapon from which a dangerous projectile may be propelled by an explosive, or by gas or air. Firearm
does not include a smooth bore rifle or handgun designed and manufactured exclusively for propelling by a spring, or by gas
or air, BBs not exceeding .177 caliber.
(e) “Pistol” means a loaded or unloaded firearm that is 26 inches or less in length, or a loaded or unloaded firearm that by its
construction and appearance conceals itself as a firearm.
(f) “Purchaser” means a person who receives a pistol from another person by purchase, gift, or loan.
(g) “Seller” means a person who sells, furnishes, loans, or gives a pistol to another person.
(h) “Shotgun” means a firearm designed or redesigned, made or remade, and intended to be fired from the shoulder and
designed or redesigned and made or remade to use the energy of the explosive in a fixed shotgun shell to fire through a smooth
bore either a number of ball shot or a single projectile for each single function of the trigger.
(i) “Short-barreled shotgun” means a shotgun having 1 or more barrels less than 18 inches in length or a weapon made from
a shotgun, whether by alteration, modification, or otherwise, if the weapon as modified has an overall length of less than 26
inches.
(j) “Rifle” means a firearm designed or redesigned, made or remade, and intended to be fired from the shoulder and designed
or redesigned and made or remade to use the energy of the explosive in a fixed metallic cartridge to fire only a single projectile
through a rifled bore for each single pull of the trigger.
(k) “Short-barreled rifle” means a rifle having 1 or more barrels less than 16 inches in length or a weapon made from a rifle,
whether by alteration, modification, or otherwise, if the weapon as modified has an overall length of less than 26 inches.
History:
1931, Act 328, Eff. Sept. 18, 1931;
?
CL 1948, 750.222;
?
Am. 1964, Act 215, Eff. Aug. 28, 1964;
?
Am. 1978, Act 564, Imd. Eff. Dec. 29,
1978;
?
Am. 1992, Act 217, Imd. Eff. Oct. 13, 1992;
?
Am. 2001, Act 135, Eff. Feb. 1, 2002;
?
Am. 2012, Act 242, Eff.

FIREARMS LAWS OF MICHIGAN — 2013
Page 8
FIREARMS
Act 372 of 1927
AN ACT to regulate and license the selling, purchasing, possessing, and carrying of certain firearms, gas ejecting devices,
and electro-muscular disruption devices; to prohibit the buying, selling, or carrying of certain firearms, gas ejecting devices,
and electro-muscular disruption devices without a license or other authorization; to provide for the forfeiture of firearms and
electro-muscular disruption devices under certain circumstances; to provide for penalties and remedies; to provide immunity
from civil liability under certain circumstances; to prescribe the powers and duties of certain state and local agencies; to prohibit
certain conduct against individuals who apply for or receive a license to carry a concealed pistol; to make appropriations; to
prescribe certain conditions for the appropriations; and to repeal all acts and parts of acts inconsistent with this act.
History:
1927, Act 372, Eff. Sept. 5, 1927;
?
Am. 1929, Act 206, Imd. Eff. May 20, 1929;
?
Am. 1931, Act 333, Imd. Eff. June 16, 1931;
?
Am. 1980,
Act
345, Eff. Mar. 31, 1981;
?
Am. 1990, Act 320, Eff. Mar. 28, 1991;
?
Am. 2000, Act 265, Imd. Eff. June 29, 2000;
?

The People of the State of Michigan enact:
28.421 Definitions; lawful owning, possessing, carrying, or transporting of pistol greater than 26 inches in
length; firearm as pistol.
Sec. 1. (1) As used in this act:
(a) “Felony” means that term as defined in section 1 of chapter I of the code of criminal procedure, 1927 PA 175, MCL 761.1,
or a violation of a law of the United States or another state that is designated as a felony or that is punishable by death or by
imprisonment for more than 1 year.
(b) “Firearm” means a weapon from which a dangerous projectile may be propelled by an explosive, or by gas or air. Firearm
does not include a smooth bore rifle or handgun designed and manufactured exclusively for propelling by a spring, or by gas
or air, BBs not exceeding .177 caliber.
(c) “Misdemeanor” means a violation of a penal law of this state or violation of a local ordinance substantially corresponding
to a violation of a penal law of this state that is not a felony or a violation of an order, rule, or regulation of a state agency that
is punishable by imprisonment or a fine that is not a civil fine, or both.
(d) “Peace officer” means, except as otherwise provided in this act, an individual who is employed as a law enforcement
officer, as that term is defined under section 2 of the commission on law enforcement standards act, 1965 PA 203, MCL 28.602,
by this state or another state, a political subdivision of this state or another state, or the United States, and who is required to
carry a firearm in the course of his or her duties as a law enforcement officer
.
(e) “Pistol” means a loaded or unloaded firearm that is 26 inches or less in length, or a loaded or unloaded firearm that by its
construction and appearance conceals it as a firearm.
(f) “Purchaser” means a person who receives a pistol from another person by purchase or gift.
(g) “Reserve peace officer”, “auxiliary officer”, or “reserve officer” means, except as otherwise provided in this act, an
individual authorized on a voluntary or irregular basis by a duly authorized police agency of this state or a political subdivision
of this state to act as a law enforcement officer, who is responsible for the preservation of the peace, the prevention and
detection of crime, and the enforcement of the general criminal laws of this state, and who is otherwise eligible to possess a
firearm under this act.
(h) “Retired police officer” or “retired law enforcement officer” means an individual who was a police officer or law
enforcement officer who was certified as described under section 9a of the commission on the law enforcement standards act,
1965 PA 203, MCL 28.609a, and retired in good standing from his or her employment as a police officer or law enforcement
officer.
(i) “Seller” means a person who sells or gives a pistol to another person.
(j) “State court judge” means a judge of the district court, circuit court, probate court, or court of appeals or justice of the
supreme court of this state who is serving either by election or appointment.
(k) “State court retired judge” means a judge or justice described in subdivision (j) who is retired, or a retired judge of the
recorders court.
(2) A person may lawfully own, possess, carry, or transport as a pistol a firearm greater than 26 inches in length if all of the
following conditions apply:
(a) The person registered the firearm as a pistol under section 2 or 2a before January 1, 2013.
(b) The person who registered the firearm as described in subdivision (a) has maintained registration of the firearm since
January 1, 2013 without lapse.
(c) The person possesses a copy of the license or record issued to him or her under section 2 or 2a.
FIREARMS LAWS OF MICHIGAN — 2013
Page 9
(3) A person who satisfies all of the conditions listed under subsection (2) nevertheless may elect to have the firearm not be
considered to be a pistol. A person who makes the election under this subsection shall notify the department of state police of
the election in a manner prescribed by that department.





That's all I can find this morning,there may be more contained therein so proceed with caution.

Is it legal to build? Would it be just a firarm?

Is it legal to build? Would it be just a firarm?

I'll go with 750.222 ,D) a firearm
But I am not a lawyer.