Commercial vs. MILSPEC buffer tubes

The information here only applies to factory-issued AR15's. If the rifle was factory-issued as a fixed stock and someone put an aftermarket collapsible stock on it, you can only GUESS. To be sure, measure the buffer tube outside diameter: 1.14" is Mil-Spec, while 1.17" is Commercial.

Commercial tubes are offered by: Bushmaster, DPMS/Panther Arms/Remington, Olympic Arms, Armalite (might have switched recently)
MIL-SPEC tubes are offered by: Colt, LMT, Vltor, CMT, Stag, Smith and Wesson

Buttstocks

	BH BUTTSTK MAGAZINE PCH BLK Fits all standard buttstocks and carries most rifl ... Code: BH52BS16BK Price: $23.40 30 available for immediate delivery Quantity in Basket: none
	BH BUTTSTK MAGAZINE PCH M4 COLLAPSIBLE BK Fits all CAR15 and M4 type collapsible buttstocks ... Code: BH52BS17BK Price: $22.50 110 available for immediate delivery Quantity in Basket: none
	CAA adj. cheek piece only for CBS stk Adjustable cheek piece for CBS Picatinny rail. Cla ... Code: CAAACP Price: $18.00 8 available for immediate delivery Quantity in Basket: none
	Magpul UBR AR15 adj stock BLK Magpul Industries Utility Battle Rifle stock inclu ... Code: MPIMAG330BLK Price: $238.50 Sorry, we are currently sold out of this item. Quantity in Basket: none
	Magpul UBR AR15 adj stock FDE Magpul Industries Utility Battle Rifle stock inclu ... Code: MPIMAG330FDE Price: $238.50 Sorry, we are currently sold out of this item. Quantity in Basket: none
	Magpul UBR AR15 adj stock FOL Magpul Industries Utility Battle Rifle stock inclu ... Code: MPIMAG330FOL Price: $238.50 99 available for immediate delivery Quantity in Basket: none
	Magpul UBR AR15 adj stock OD Magpul Industries Utility Battle Rifle stock inclu ... Code: MPIMAG330OD Price: $238.50 Sorry, we are currently sold out of this item. Quantity in Basket: none
	MAGPUL MOE carbine stock MIL-SPEC BLK MOE M4 Carbine Collapsible Butt-Stock Military Mod ... Code: MPIMAG400BLK Price: $54.00 Sorry, we are currently sold out of this item. Quantity in Basket: none
	MAGPUL MOE carbine stock MIL-SPEC FDE MOE M4 Carbine Collapsible Butt-Stock Military Mod ... Code: MPIMAG400FDE Price: $54.00 2 available for immediate delivery Quantity in Basket: none
	MAGPUL MOE carbine stock MIL-SPEC FOL MOE M4 Carbine Collapsible Butt-Stock Military Mod ... Code: MPIMAG400FOL Price: $54.00 Sorry, we are currently sold out of this item. Quantity in Basket: none
	MAGPUL MOE carbine stock MIL-SPEC OD MOE M4 Carbine Collapsible Butt-Stock Military Mod ... Code: MPIMAG400OD Price: $54.00 Sorry, we are currently sold out of this item. Quantity in Basket: none
	MAGPUL MOE carbine stock NON MIL-SPEC BLK MOE M4 Carbine Collapsible Butt-Stock Commercial M ... Code: MPIMAG401BLK Price: $54.00 Sorry, we are currently sold out of this item. Quantity in Basket: none
	MAGPUL MOE carbine stock NON MIL-SPEC FDE MOE M4 Carbine Collapsible Butt-Stock – Commerci ... Code: MPIMAG401FDE Price: $54.00 768 available for immediate delivery Quantity in Basket: none
	MAGPUL MOE carbine stock NON MIL-SPEC FOL MOE M4 Carbine Collapsible Butt-Stock – Commerci ... Code: MPIMAG401FOL Price: $54.00 Sorry, we are currently sold out of this item. Quantity in Basket: none
	MAGPUL MOE carbine stock NON MIL-SPEC OD MOE M4 Carbine Collapsible Butt-Stock – Commerci ... Code: MPIMAG401OD Price: $54.00 Sorry, we are currently sold out of this item. Quantity in Basket: none
	Buttstock, for AR-15/M-16, 6-pt. M4, Tapco The M4 carbine style, collapsible buttstock is mad ... Code: TINCSTK9161B Price: $72.00 Sorry, we are currently sold out of this item. Quantity in Basket: none
	Buttstock, for AR-15/M-16, 6-pt. M4 FDE, Tapco The M4 carbine style, collapsible buttstock is mad ... Code: TINCSTK9161D Price: $72.00 Sorry, we are currently sold out of this item. Quantity in Basket: none
	TAPCO AR EXTENSION TUBE KIT MIL-SPEC Tapco, Inc. Mil-Spec Black Tube, Spring, Buffer, C ... Code: TINZAR09106 Price: $63.00 885 available for immediate delivery Quantity in Basket: none
	TAPCO AR EXTENSION TUBE KIT COMMERCL Tapco, Inc. Commercial Black Tube, Spring, Buffer, ... Code: TINZAR09108 Price: $49.50 Sorry, we are currently sold out of this item. Quantity in Basket: none
	UTG 6-POS STK ASSEMBLY MIL-SPEC BLK Leapers, Inc. - UTG Model 4 Stock Black w/ Buffer, ... Code: UTGRBU6BM Price: $46.40 1646 available for immediate delivery Quantity in Basket: none