While I know headspace should be a non-issue with quality parts (I am using a Krieger barrel and Young National Match chrome bolt), it makes me nervous not to check. It appears one needs to remove the ejector and spring, and that looks it requires a bolt ejector tool. The cheapest I can find is at Sinclair International for about $25. Is there a way to get the ejector out without the tool, or am I in for fight? I guess one part of me keeps asking do I need to spend nearly $50 ($20 for gauge, $25 for tool) to check for something that has a high chance of being right.
You do not need to remove the ejector. If you are using a MILSPEC gage you simply insert and check. If you are using a civilian one (make sure you have the right one) then you only need to remove the extractor and apply moderate finger pressure.
I had the rifle chambered in 223 Remington, not 5.56, so it appears I will need to pull the ejector. I will probably order the Sinclairs ejector removal tool. At $25, it would be worth not having to curse at not having three hands to remove the ejector (and reinstall).
I use a Forster .223 field headspace gauge and never had to remove my ejector, only the extractor. I’m getting a 5.56 field gauge from Bill Ricca next week that requires no removal of parts. Are you absolutely sure you have to remove the ejector?
If that part is 799734, NSN 4933-00-070-7814, then it says the gauge is clearanced for the ejector and extractor, and no, no disassembly is needed. Note that gauges will be different for 2.23 and 5.56, and that this gauge is for measuring maximum headspace. It looks like a NO-GO or FIELD gauge to me, but not enough info there to tell.
IG has a few of the Bill Ricca gauges, they are apparently the equivalent of field headspace gauges if I recall his posts. If you’re going to use something like a Forster .223 gauge, you won’t need to take the ejector out.
Not disagreeing with you at all, but why no need to remove the ejector with a Forster .223 gauge? Is the base of gauge sized to clear the ejector, or…?
Because the instructions I got with the gauge said only to remove the extractor. It isn’t cut to clear the ejector but it appears that the ejector has no effect on the use of the gauge. I only use Field gauges for my annual inspection, I don’t bother with go/ no go.
OK, not 100% sure why that is, but given you should never be able to close the bolt on the Field gauge, ejector or not, I can see why this makes sense.
His gages are essentially MILSPEC surplus gages. They are identical to those I used in the .MIL. I have seen Forster and Clymers gages that gave incorrect readings on MILSPEC M4’s. If Bill Ricca is out, Bushmaster makes and sells a 5.56 Field Headspace gage. Again, as spam has pointed out, the ejector does not need to be removed.
I have been wanting to ask you guys some headspacing questions, if someone could be so kind to enlighten me a bit.
I only own the Bill Ricca USGI Maximum HS gauge. It is marked “1.4730 MAX Field Service”
Despite years of armorer work, I have never personally needed to mess around with headspacing, but I would like to now learn a thing or two. Here are my questions I am hoping to obtain some definitive answers to:
What exactly measures “1.4730”. I have taken my quality mics/dial calilpers, and I cannot come up with that exact measurement anywhere. IOW’s, is there a particular part of the HS gauge, that is supposed to measure “1.4730” long or what? WHAT is actually supposed to be “1.4730” long??? It damn sure isn’t the overall length of the HS gauge.
Are all of the Ricca Maximum HS gauges magnetic? Mine is magnetic as hell, and I damn sure didn’t magnetize it. I assume this is done purposefully, possibly to make the gauge stick to the bolt? However, in all my years of reading, I’ve never heard mention of a HS gauge being magnetic.
Am I correct that THE PROPER WAY to use this HS gauge, is to insert it into the chamber of my upper, and then install my bcg and charging handle, and then I am supposed to make sure the bcg does NOT close down completely? IOW’s, I just need to make sure that the charging handle doesn’t lock, and I need to also make sure the bcg is PROTRUDING out the back of the upper?
At what point do I have a problem, (ie - a measurment showing a worn out bolt?) Would that be when the carrier DOES shut completely, and DOES flush out with the rear of the upper receiver?
Here’s a biggie: WHAT EXACTLY am I using this headspace gauge to measure on my AR15 bolt? I mean, I know I am looking for WEAR, but WHERE?
Am I possibly looking for WEAR on the BACKSIDE of the BOLT LUGS? I would think this is the only place I could possibly be looking for wear on the bolt, UNLESS I am possibly looking for BOLT FACE WEAR? (doubtful)
My best guess is that I’m using a HS gauge to check for wear on the REAR/BACKSIDE of the LUGS of the bolt, because every time the bcg cycles, it pulls rearward on the bolt, and the backside of the bolt lugs are wearing on the front side of the bbl extensions lugs.
IS THIS CORRECT? IF NOT, then where EXACTLY on the bolt am I looking/measuring for wear?
is head spacing something everyone always checks? i never really have, i thought with ar15’s that quality parts should never have issues. i guess it is better safe than sorry though
This is what I know, but others may be more knowledgeable and am sure will chime in.
The distance is from the face of the bolt to a datum line about midway on the tapered part of the chamber. You can’t measure it, 'cause you can’t see it. Don’t worry about this…the gauges are cut to contact the right spot in the chamber.
Can’t comment on being magnetic. The Forster ones I borrowed for a .223 are not magnetic.
3 - 4) For the GO gauge, install, and if the bolt closes and locks, you have ENOUGH headspace. The GO gauge is the shortest of the three gauges , and you need to be sure there is enough room for the case to expand a bit and/or for the bolt not to jam the round into the chamber. It would be rare for there not to be enough headspace.
Next, try the NO-GO gauge, which is longer than the GO, but shorter than the FIELD. The bolt should NOT close on the NO-GO. If it does, it means there is more than desirable headspace. This means the case can expand more than desired. Cases may not last long under reloading, since there would be considerable case resizing.
If the NO-GO gauge permitted closure, then try the FIELD gauge. This is the longest gauge of all and if the bolt closes and locks on this, there is so much headspace, you are in a dangerous condition, where a cartridge could separate or something else bad happen.
You have this right, bolt wear on the lugs where they contact the barrel lugs is where wear will take place, and headspace will grow. I can’t say how long such wear will take, but if well lubed, the onset of excessive headspace may take place only after the barrel is shot out. Can’t say for sure on that.
My Forster gauges sizes.
GO 1.4636"
NO-GO 1.4666"
FIELD 1.4696"
The dimensions are very narrow in range, just .006" of an inch, from minimum to unacceptable, the thickness of two human hairs, give or take!
No tmckay2,
HS is not something everyone checks at all. In fact, most guys do not, and it’s certainly not needed, especially on a new rifle, 99% of the time anyway.
Some of us here are true AR junkies, with severe BRD, and we all cannot sleep at night if we don’t own literally every Armorers tool known to mankind.
Of course, there are a few professionals around here who truly do get use out of their HS gauges. Even they don’t have a daily need for them, especially with quality built, new rifles and carbines.
Simply put, you’re fine without a HS gauge, and you always will be so long as you stick with quality built AR’s and parts.
Razorhunter is right. I borrowed headspace gauges, and did so just to make sure all was OK, though I am 99.9% sure it will be. And besides, like stated earlier, I get to buy another tool, a bolt ejector tool. AR shopping can be dangerous to your wallet.
