Home› Main Category› General Firearms
hawk18
Senior MemberOrygunPosts: 742 Senior Member
AR tools
I didn't want to high jack Uncle Festers thread, but, my question is: When you guys are building uppers or swapping barrels or swapping bolts, do you use head space gauges? I'm fixen to swap out the barrel and hand guard on an AR and have never done that before.
Hawk
Hawk
Replies
Headspace gauges confirm several things for you:
1. The bolt and barrel will be compatible with each other. You're usually OK using a new bolt and barrel from the same manufacturer, but everybody has a bad day from time to time, and if you're pairing an old of one with a new of another, it's anybody's guess.
2. Whoever put the gun together did it right, at several points in the process.
3. The gun will operate safely. Excessive headspace in an AR can not only lead to the usual problems of case head separation, but also to primers popping out of pockets and rattling around inside the firearm, where they can jam up the works in several ways.
To do it right, you need a set of three - properly from the same manufacturer, and you'll want to know going in if you're dealing with .223 or 5.56 chamber specs:
1. Field. This is the biggest, "gun is screwed up" gauge. If your rifle can lock into battery with that, you've got problems.
2. NO-GO . Rifle ideally should not chamber this one, but not the end of the world if it does - so long as it does not also chamber the Field gauge. Be aware that beyond here there be dragons You'll have shorter brass life and have a higher risk of case head separations on multi-use brass. Better to find a bolt/barrel combo that locks up properly.
3. GO. Basically a hardened steel dimensional copy of a live cartridge.
"Nothing is safe from stupid." - Zee
― Douglas Adams
Next question: I'm changing from an unfired .223 Rem bolt and barrel to an unfired 6 mm x 45. According to Pacific Tool and Gauge, the.223 Rem set will work for both cartridges. Do you feel this is correct.
Hawk
― Douglas Adams
"Nothing is safe from stupid." - Zee
Hawk