I built my first upper with a DD upper receiver and Noveske 10" 300 BLK barrel. Is it essential to get the “go” and “no go” go headspace gauges and check this? I want to be safe, but I also don’t want to spend $55 for something that I may never use again and really don’t need.
On an AR, headspacing is set by the barrel extension and the bolt dimensions. If you get a quality bolt to go with your Noveske barrel you should not need a headspace gauge. It’s nice to have for some reassurance, but not really needed when using quality, new parts.
Thanks for the info. I have a new BCM Bolt Carrier group so hopefully this won’t be a problem.
Sorry, I just realize this is in the “tech” section and I meant to put this in the custom build thread.
BCM is top quality, so it really shouldn’t be a problem. It’s one of those things where the only way to truly know is to check it, but buying new, quality parts it will be within spec 99.9% of the time, or more.
I would say this is the right place for your post. Sounds like a great SBR upper.
I had ADCO do my barrel work… 
Thanks! I have a Troy TRX Extreme Rail, AAC Breakout, Magpul AFG2, Gear Sector Light mount for a Surefire E1B with a Malkoff VME head and M31 drop in for 200 lumens. I’ll be getting the new AAC 762 SDN-6 suppressor once they are available and an Eotech EXPS 2-0.
This will be the lightest AR I have.
I see a 300 in my future. I love the fact no bolt or magazine changes are necessary. Make sure to post some photos in the SBR photo thread.
How much is your life or well being worth?
That’s what really matters. 99.9% of the time you’ll be fine w/o checking with a NO-GO or FIELD gauge. IF however you end up with excessive headspace and the rifle blows up it could harm or kill you or an innocent bystander.
So it really depends on how want to play the odds. Murphy is a motherf***er and I don’t like him at all, so I check EVERYTIME.
A wise person not needing the gauges but once would just buy the gauges check your own stuff and then sell the gauges after you’re done.
+1 to Robbs advice. There’s a reason this is required in the tech manual. Those are all Colt or FN guns but it’s still required.
Robb, do the gages cost $55? I thought they were a little cheaper.
Thanks
My USGI 5.56mm NATO FIELD gauges cost me about $30. I can’t remember what I paid for my Colt FIELD II 5.56mm NATO gauge but it was under $55.
I tend to agree that if you are using high quality components from well known manufacturers, it should be a non-issue. But, I agree with Robb. I always check the headspace as well as firing pin protrusion, etc…
Go to billricca.com. Look in his collectors area for M16 stuff. He still has the maximum headspace gage (Field gage) listed on his site. They are 35.00.
Thanks for the info, however, my build is a 300 BLACKOUT.
Can you give me more information about “firing pin protrusion”? I have an idea of what it is, but can you go into some detail about this? Feel free to PM me. If not, no worries. I know how busy people can be, including myself and I can do some research. Perhaps if you could just recommend a resource for the information, that would be great.
Midway has the “go” and “no/go” gauge for $28 each for this caliber.
Robb, your advice is well taken. I spend about $40,000 a year for all of the insurance that my family and I have. $56 is a small price to pay.
Sorry, I didn’t see the part about it being a 300 Blackout.
No worries. Your posts are always informative and I appreciate you sharing your wealth of knowledge!
Appreciate the reference to Bill’s site.
The gauge listed is for max gage. (no-go?)
Question: What about a “go” gage - wouldn’t that be needed as well?
Thanks.
(as I am about to build my first, I am listening carefully)
A GO-gauge is only needed for gunsmiths who make their own barrels. It’s to check for enough headspace to chamber a live round.
I have a GO gauge but really don’t need it nor very rarely use it.
I use a NO-GO and a USGI FIELD and Colt FIELD II most often. I prefer when assembling a new upper to have it not close on a NO-GO or FIELD gauge. After a few thousand rounds pretty much all 5.56mm NATO chambered guns will close on a NO-GO but not on a FIELD.
Got it - thanks!