Adan Arms P2 chamber confusion

Knightfire8 · March 22, 2018, 08:01 AM

I am looking to purchase a P2 Adam Arms AR15 from an online store and I am confused to the chamber size. One description says it is chambered in .223/5.56 and the same firearm has a description of 5.56x45. This is the exact same firearm down to the SKU#. I have asked the store which it is, but have no response yet. Does anyone know what Adam Arms sends from its factory to stores in regards to the chamber size? This is very frustrating. Thanks!

G.barnes · March 22, 2018, 10:33 AM

They're rated for 556 so you can also use 223

Theohazard · March 24, 2018, 07:50 PM

Don’t worry about it. There are almost no ARs made at the moment that are truly chambered in .223. I can’t even think of any off the top of my head. Manufacturers tend to use ”.223” and “5.56” interchangeably, and this causes a tremendous amount of confusion among people new to ARs.

I’ve seen many ARs (and other semi-auto rifles) that were labeled “.223” on the receiver but are actually chambered in 5.56 and say so on the barrel. Many others are marketed as “.223” but — like almost all the rest — are actually chambered in 5.56. Colt’s venerable 6920 is often labeled “.223” on the box but has always been chambered in 5.56.

So buy the rifle and feel confident that you can shoot both .223 and 5.56 interchangeably.

LBussy · March 25, 2018, 09:25 AM

Knightfire8, the 5.56 x 45 round is officially known as 5.56 NATO; they are the same thing. The "45" part is the length of the cartridge and is a lesser-used method of describing the same chambering. (I did not see anyone address the question of the cartridge length.)

Knightfire8 · March 27, 2018, 08:18 AM

Thank you all for the information.

March 22, 2018, 08:01 AM	#1
Knightfire8 Junior Member Join Date: March 14, 2018 Posts: 3	Adan Arms P2 chamber confusion I am looking to purchase a P2 Adam Arms AR15 from an online store and I am confused to the chamber size. One description says it is chambered in .223/5.56 and the same firearm has a description of 5.56x45. This is the exact same firearm down to the SKU#. I have asked the store which it is, but have no response yet. Does anyone know what Adam Arms sends from its factory to stores in regards to the chamber size? This is very frustrating. Thanks!

March 24, 2018, 07:50 PM	#3
Theohazard Senior Member Join Date: April 19, 2012 Location: Western PA Posts: 3,829	Don’t worry about it. There are almost no ARs made at the moment that are truly chambered in .223. I can’t even think of any off the top of my head. Manufacturers tend to use ”.223” and “5.56” interchangeably, and this causes a tremendous amount of confusion among people new to ARs. I’ve seen many ARs (and other semi-auto rifles) that were labeled “.223” on the receiver but are actually chambered in 5.56 and say so on the barrel. Many others are marketed as “.223” but — like almost all the rest — are actually chambered in 5.56. Colt’s venerable 6920 is often labeled “.223” on the box but has always been chambered in 5.56. So buy the rifle and feel confident that you can shoot both .223 and 5.56 interchangeably. __________________ 0331: "Accuracy by volume."

March 25, 2018, 09:25 AM	#4
LBussy Senior Member Join Date: February 26, 2012 Location: Kansas City, MO Posts: 296	Knightfire8, the 5.56 x 45 round is officially known as 5.56 NATO; they are the same thing. The "45" part is the length of the cartridge and is a lesser-used method of describing the same chambering. (I did not see anyone address the question of the cartridge length.) __________________ -- Lee Bad decisions make good stories.

March 22, 2018, 10:33 AM	#2
G.barnes Senior Member Join Date: June 3, 2011 Posts: 182	They're rated for 556 so you can also use 223

March 27, 2018, 08:18 AM	#5
Knightfire8 Junior Member Join Date: March 14, 2018 Posts: 3	Thank you all for the information.