I built many without checking headspace. After getting my gauges I checked everything I had and found no issues. I've had it come up once, personally, and it was a 5.56 marked barrel that didn't pass 5.56 go, but did pass .223 go, that probably would have functioned.
Headspace being out of spec in the AR can result in function issues, accelerated wear, poor accuracy, damaged brass, popped primers, and other non-catastrophic issues. It has to be VERY bad to actually cause safety issues.
How many people with ARs have shot them a bunch? How many people do you know with cheap guns that have intermittent issues, or issues with weak ammo, hot ammo, or some other mix?
There isn't a widespread issue of bad headspace plaguing the AR world. There is a widespread issue of poor information, companies that shout "MIL SPEC" with no ability to actually hold tolerances and properly control their quality to ensure it meets spec, and the assumption that "just as good" means your $300 parts build is of the same performance and quality as a $1000 rifle built by a quality shop.
There are videos and photos out there of all kinds of wacky stuff. Anderson lowers in blister packs at a store with no magwell cutout is one of my favorites - "mil-spec is mil-spec, only 4 forges, just as good!"
Excellent comments, Rustpot; thanks.
“A man hears what he wants to hear and disregards the rest.”
— Simon & Garfunkel, The Boxer, 1970
|fugitive from reality|
The gauging schedule varies, but some rifles don't see a headspace gauge for up to four years at a time. The gauges themselves however, are in almost constant use. I spent some time in depot level maintenance working with the full time small arms guys, and they just don't treat their gauges with the same reverence that you seem to suggest. It's not that the gauges are 'free', it's the fact that they're just not that fragile. The part of the gauge that's important to keep pristine is the shoulder cut at the very front. The idea that the gauge may scrape against the side of the chamber just isn't an issue because the amount of ejector spring pressure is minimal.
'I'm pretty fly for a white guy'.
|fugitive from reality|
The spring loaded extractor is designed to snap over the rim of the cartridge as the bolt closes. This is an extremely reliable design that has been through billions and billions if not trillions of rounds in many different rifle and pistol designs. That being said you don't drop the bolt on a headspace gauge. There are sometimes just a few thousandths of an inch between pass and fail, and dropping to bolt can cause false readings.
The procedure I was taught only works if the ejector is either removed, you have a gauge with the rim rebated, or you have a receiver mounted ejector. The gauge is placed on the face of the bolt, under the extractor. The bolt is closed by hand, until any resistance is felt. In the case of an AR, you close the bolt carrier group by bushing against the back of the BCG with your thumb. You will feel two or three point of contact as either the locking lugs or the gauge shoulder contacts something. Apply a little more pressure and you'll quickly figure out if it's the bolt rotating shut, or it's the gauge solidly contacting the shoulder of the chamber.
There are some very specific gauges out there. One of them is an extension headspace gauge. It only measures the barrel extension itself, but it can help determine exactly what's out of spec.
'I'm pretty fly for a white guy'.
The point is that though the rate of issues with AR-15 Headspace is pretty low it isn't Zero. I've had 2 AR-15's with chamber issues, one was a top tier Match rifle with a VERY tight chamber (and sold as such), the other was a cheap POS from a unlamentedly gone manufacturer that required a bolt swap to get into spec and function. I've had quite a few AR-15's but certainly less than 100. I would "guesstimate" the problem rate at maybe 1-2% or less. Again Very low but not Zero.
Normaly people could probably assemble a couple dozen AR's and never see an issue. It's UNLIKELY that there will be an issue. But again it's nice to KNOW that there is NOT a headspace issue with my rifles and we can move on to things like Properly staked bolt carriers etc etc........
Remember, this is all supposed to be for fun...................
The depot should 100% verify the gauges on a schedule to maintain in house certification, if not send them out for certification. Any quality department does this. If they don't they are 100% wrong and will not pass any outside quality standard or audit.
I'm not talking about them. They should have training and budgets for this. The can chart wear/replacement over labor and material costs and find a good ratio that determines the best business case. Or they're just doing what's easy at greater expense with no actual idea of how to run a quality department.
End users, hobbyists, whoever, do not have a quality department. Gauges do not get verified.
I know how fragile gauges are. I'm not worried about 10 uses or 50 uses. I'm worried about my gauges falling out of spec as I use them for the rest of my life. No spring pressure to force metal on metal drag on the gauge. No requirement to overcome a 5-15lb ejector spring against the critical gauge faces. I suspect, depending on use, I will eventually send them out for verification if the cost is less than replacing the gauges for piece of mind.
By the way, this is part of my job. I'm the engineering manager for a small manufacturing company. I run our quality program. I am responsible for all code compliance. I write the standards, train the employees, and develop the system to assure compliance.
|Powered by Social Strata||Page 1 2 3|