Headspace is set when the barrel extension is mounted to the barrel.
You can buy the gauges if you want to be "sure".
Clearly, no one here has gauges that they are willing to assist with.
I posed the same request over the summer with the offer of buying a lunch, coffee, or beer.
Couldn't find a anyone with a set.
Good luck.
The barrel extension comes already mounted to the barrel. The extension has a post on it the will index into the notch in the upper receiver to align it. Grease the outside of the extension and inside the upper receiver so that everything goes together smoothly. I tighten and then loosen the barrel nut three times, then tighten it one last time, check the alignment where the gastube will pass on the nut with the hole in the upper receiver. Tweak tighter if necessary to get it right. Torque range is from 30 to 90 ft pounds, anything past 30 is good if it aligns.
Im still not quite sure why people feel they need a "set" of gauges for a brand new rifle. You would only need a .223/5.56 NO GO. That is what you are concerned about. A go gauge is essentially your factory loaded round. No blow up condition happens if the bolt wont close on a in spec round. The problems happen when a bolt closes on a in spec round and the headspace has too much space between the face of the bolt and the face of the cartridge case. Your bolt SHOULD NOT close on a NO GO gauge. If it does then you have excessive headspace and that will lead to KABOOM of your receiver/rifle. Shouldn't ever need a Field Gauge for a brand new rifle.If I had a set of gauges, I would gladly loan them out. However, I haven't found a reason to spend 80$ on a set yet...
+1Op, if your ever in South Bend look me up I have field~go~no go gauges for most popular calibers. Anyone who endorses NOT bothering to check head space on a personal build is gambling with the PSI the round in question produces just inches from their face. (50K range on 5.56 loads)
Buy the gauges if your assembling or building rifles, what's it worth to keep your face and eyes intact!?
I have a Hornady chamber gauge and also NO GO gauges for every caliber of rifle I own. The field and GO gauge are useless to me.Its always a good idea. I always check with any (for sure non matching) mosin/Mauser/Enfield or an AK build. My AR builds I have not in the past. not saying its good practice though. Im not really a fan of that anymore though. The more I read the more I think manufacturers with AR parts suck. It turns out many 5.56 marked chambers aren't truly in spec with, well, a 5.56 chamber. Read up on that in your own time, that's a whole other issue but my next AR build I will be probably buying gauges or finding some. A chamber checker or reamer would be cool too (anyone have one?). Checking headspace, even if its "always" good is something you can do to help make sure you have a safe rifle. Might as well do all you can to limit any variables you can.
That being said, anything I build gets fired from as far away from me as possible.... . Anyone ever get questioned why you have a motorcycle helmet at a range before? Haha.
Stay safe!