…where can I find a set of the proper headspace gauges in .556 Nato? I’ve spoken with some of the well known manufacturers and they do not make them in 556…only in .223. What are you guys using for your headspace gauges and where are you getting them?
ThanK You
ullie
I bought a USGI FIELD gauge a long time ago on TOS. I also have set of Forster .223 gauges in GO, NO-GO and FIELD. Brownells indicates these and 5.56mm NATO are the same. So usually I use the NO-GO, the FIELD and then the USGI FIELD. Some of my guns will close on a Forster NO-GO but not a USGI FIELD.
Randall posted some interesting info here and a link to the gauge you might need.
https://www.m4carbine.net/showthread.php?t=6680
Are you familiar with the dimensions of the different gauges?
Here is my headspace info collection.
Forester will sell you individual gauges in specific dimensions if you ask nicely.
A civilian 223 field is 1.4696-1.4670 and a military 556 field is 1.4728-1.4730…can you use the 223 gauges in 556 chambers?..are the differences in length between the two not an issue? …in otherwords can i use 223 gauges to check headspace in a weapon with 556 chambers such as an LMT or Colt…
…for example a 223 field is 1.47000 and a military 556 no go is 1.4706…a difference of .0006…so they are basically equavilent…but one indicates a relatlvely safe condition and the other a reliatively unsafe degree of headspace…i would think that you should only use a 556 gauge in a 556 chamber…or do such small differences not matter…
…i am not a gunsmith…far from it…i have a new (less than 200 rounds fired) Bushmaster upper that came with a new Bushmaster BCG ( semi unshrouded carrier)…i would like to drop in a new BCM standard auto BCG…do i need to be concerned with headspacing it…i have been told that since both the upper and bolt/carrier group are new headspace will not be an issue…
The only gauge you need to own is this one.
If your rifle will accept that gauge, the bolt or barrel or both are worn out and should be replaced.
Short of owning that gauge, any 1.473" or 1.474" can be used as a maximum length.
It requires the the ejector be removed to properly test the headspace, correct? Why not have a cut-out in the rim of the gauge so headspace can be tested without removing the ejector?
I use the USGI FIELD because it’s easier to use without pulling the ejector or extractor. It’s releived in those areas. With the Forsters you can leave the ejector and extractor on but it’s a real bitch to push the bolt forward enough and then remove…although I’ve done it a few times that way.
That’s what I did.
30 seconds on the surface grinder.
You don’t have to pull the extractor to use an un-modified forester gauge.
I just snap the gauge under the ejector and slide the carrier into the receiver.
The gauge comes right back out afterwards.
I’ll try that.
You do need to pull the ejector though, or grind a little slot in the base of the gauge to clear the ejector plunger.
Randall-Please check your PM.
Randall…Thank You Sir…that is what I was looking for…and thank you for all the additional information…it really helped…
ullie