http://www.ar15.com/forums/topic.html?b=3&f=4&t=174215

I'm collecting parts to build my first AR and I just saw this and I am wondering what the hell is really going on with Homo.  It sounds like a direct contradiction to everything I have ever read (I have never built one so yes I don't "really" know what I am talking about)Please advise.  Thanks guys

I just built my first upper and I was somewhat concerned about headspacing. I bought a field length gage just to make sure there wasn't too much space. What I interpret Homo is saying is that the headspace is probably fine and at least for him and his 130 builds every bolt and barrel has been in spec.... But shit does happen (Tweaks post) that's why I bought a field gage, peace of mind. BTW mine wouldn't close on the field gage, so at least I know the headspace isn't excessive.

Tweak used to assemble ARs for a living at Olympic Arms. Homo_whatver has no verifiable experience or accountability.

Who are you more inclined to believe?

From the comfort and anonymity of my computer I could sit here and tell you that I used to be the designated armorer for SEAL Team Six, but without a verifiable pedigree I'd just be another Internet dipshit blowing sunshine up your ass.

Listen to Tweak. He has [i]forgotten[/i] more about ARs than most of us will ever know.

Oh, and if it makes you feel any better I've assembled...uh...seven [b]thousand[/b] ARs, I make $45million per year, and I'm married to a Dutch supermodel. I drive a Ferrari, have a nine inch schlong, and commute to work in my own private helicopter.

I could prove all of this...but...uh, I don't have a webcam...[8)]

[:D]

Geez, dropping the resume bomb huh CJan_NH? [:)]

To clarify, IF the parts are correct you will most likely not have headspace issues. The only easy way, short of measuring all the parts and comparing the differences, to check if the parts are properly dimensioned is to use a HS gage. If you want no problems at all buy Colt bolts and barrels. You'll get proper steels (in both parts) proper Parkerizing, proper heat treat, and proper HS. A large portion of the malfs in ARs can be solved by the installation of a Colt, or otherwise USGI, barrel.

Now, if you read these boards you know that not every AR part made is made well. If that was the case we would prolly lose 30% of the threads. I don't understand some people's reluctance to treat the AR like any other firearm. All firearms get HSed. Hell, even 1911s have to be HSed and the barrel assembly on them is much simpler than that of an AR.

You're not worried so much about excessive HS as short HS. The AR has a lot of leeway in the long direction. Short HS will manifest itself as a variety of malfunctions. The most common of these being failures to eject and failures to extract. The shorter chamber does not leave sufficient room for the case to obturate forcing the extractor to work harder. Often these failures will only show up when the rifle is hot. Tolerances change as differential heating occurs, springs weaken, and parts flex.

Autoloaders need longer HS, high pressure cartridges need longer HS, full autos need longer HS. That means the AR needs longer HS to run.

The emphasis on the FIELD gage is misplaced and a result of too many people learning assembly from the military manuals. The FIELD gage is used on rifles that have already seen service. The GO and NOGO gages are used in the assembly shops. If you asemble the piece yourself, or are unclear as to who did the assembly, you ought to check the GO dimension.

FWIW, and dropping a "resume cruise missile" of my own, I use to assemble ~10 uppers a DAY. Some went with complete rifles, some were for stock, some were simply orders for uppers. In the case of my former employer [i]at that time at least[/i] every chamber had to be reamed to the correct depth. When I worked in barrel assembly (took the barrels from a rifled tube threaded on both ends to finished product) we cherry picked bolts with a median HS dimension to use in HSing the barrels. That way the finished barrels would be in the middle of the HS range when they made it to assembly. Better that they be shallow than deep. The procedure for fixing a barrel with deep HS is a bit more complex than that for a barrel with shallow HS.

Get a GO gage and a FIELD gage and don't worry about it. Most people never shoot their rifles hard enough for it to matter in either direction.

OOOOOOOOH NO.............!!!!!

not the headspace thing again !!!!!!

i have 2 NIB AR-15s (Colts) that will lock up on a "NO-GO" gage, & 5 shooters (Colts) that lock up, the other 7, a Bushy & Eagle & 5 Colts (one is a NIB) will NOT lock up, i am going to buy a FG next.....

Well that is all I needed to hear from someone who definitely knows what they are talking about. I'll be getting these two and rest peacefully knowing everything is a GO!

Def. Tweak[beer] THANKS!

The military NOGO and FIELD gages are longer than the commonly available civilian models. That is part of the confusion over headspacing. If you follow the links I provided all will be clear. [:)]

[speeling]