barrel and BCG change on ar-15

jsp10477 · April 9, 2011, 11:43 PM

I'm thinking of changing the barrel and bcg on a non milspec ar to milspec parts. Will I have to take the barrel and bcg to a smith to have the headspace set the same as a bolt gun?

amorceau · April 15, 2011, 12:27 PM

I switched out an Oly arms carry handle to a YHM flat-top. Only thing that didn't fit at first were the pivot holes. Fitting any good or really good finished AR barrel should be done with a torque wrench while following the specs off either the Marine Corps or US Army armorer's manual. Mine shot fine and I am by no means a gunsmith or armorer. I just read the directions and follow them to a "T". Which brands you looking at for the changeover?

DnPRK · April 15, 2011, 07:04 PM

Critical dimensions for headspace are well established and known to all makers of 5.56/223 AR-15s. Headspace is accomplished when the barrel extension is pinned in place. If you purchase a barrel and bolt from a reputable manufacturer, it will come correctly headspaced.

If you want extra peace-of-mind, purchase a field gage

HiBC · April 17, 2011, 02:22 PM

A YHM,DSA,etc upper receiver assembled with the small parts is about $125.
I guess if I was buying a whole BCG,and a barrel.I'd be thinking about building a complete upper,and leaving the original upper intact

April 9, 2011, 11:43 PM	#1
jsp10477 Junior Member Join Date: January 5, 2011 Posts: 13	barrel and BCG change on ar-15 I'm thinking of changing the barrel and bcg on a non milspec ar to milspec parts. Will I have to take the barrel and bcg to a smith to have the headspace set the same as a bolt gun?

April 15, 2011, 12:27 PM	#2
amorceau Junior Member Join Date: April 7, 2007 Posts: 4	barrel and BCG change on ar-15 I switched out an Oly arms carry handle to a YHM flat-top. Only thing that didn't fit at first were the pivot holes. Fitting any good or really good finished AR barrel should be done with a torque wrench while following the specs off either the Marine Corps or US Army armorer's manual. Mine shot fine and I am by no means a gunsmith or armorer. I just read the directions and follow them to a "T". Which brands you looking at for the changeover?

April 15, 2011, 07:04 PM	#3
DnPRK Senior Member Join Date: August 25, 2001 Location: LC, Ca Posts: 1,724	Critical dimensions for headspace are well established and known to all makers of 5.56/223 AR-15s. Headspace is accomplished when the barrel extension is pinned in place. If you purchase a barrel and bolt from a reputable manufacturer, it will come correctly headspaced. If you want extra peace-of-mind, purchase a field gage

April 17, 2011, 02:22 PM	#4
HiBC Senior Member Join Date: November 13, 2006 Posts: 3,057	A YHM,DSA,etc upper receiver assembled with the small parts is about $125. I guess if I was buying a whole BCG,and a barrel.I'd be thinking about building a complete upper,and leaving the original upper intact