Headspace Issue?

[kcstott]

No way the ammo is known, he doesn't have any way to measure datum lines. He could do the masking tape measurement; that's a known dimension. It works.


The gauge is 8.5mm from closing? Something messed up with that...were not talking a couple of layers of tape.

Best you gauge peeps can do is the closer to the gauge, more likely it won't blow up. But there's no guarantee it won't blow up. US made ammo is pretty close to the SAAMI spec, get something from overseas, all bets are off.

Ok the 8.5mm Dimension is the distance that the bolt carrier is still open. not how far the bolt is from closing.

Like this



Now if you partially disassemble your AK you will notice that this is where the bolt is almost fully rotated shut.

Klewan

This is not about being a fanatic, this is about taking a measurement that has the highest level of safety behind it.

What you express is throwing safety to the wind.

Using headspace gages is a proven, reliable, traceable standard. Tape?? how precise is that? and as i stated above how the hell do you know where you are starting from??

Now your statement on using the hornady headspace tool is a joke. you don't make precision measurements with a set of dial calipers.

In the machine shop dial calipers are for getting you close say +/-.001 at best. at least that is how far I'm willing to trust them. You want closer measurements
then that you need to use a drop indicator or a micrometer or something far more precise then dial calipers.

See everyone that has no experience with making precision measurements thinks caliper are as good as what they say they are. Calipers are used as a matter of feel and if you can not repeat the feel you can not repeat the measurement. this is why Micrometers are used, why we have depth mics, indicators, etc, if calipers were all anyone needed they would not have invented a micrometer.

Now no matter what you say or believe headspace gages are always to be used to set, check and verify your headspace.

Now i through in a variable for you. what if someone decided to ask you to check their headspace and you used tape to do it.
gun blows up on the guy and you get sued?? then what ?? you have no case. because they will call in expert witnesses to say your method is not recognized as a standard practice.
Now if you used a headspace gage and the rifle still blew up then it can be proven that the headspace was not the issue and the ammo needs to be brought into question.

Thats also where your statement makes no sense, you said what about unknown ammo.
Well PROPER headspace eliminates one variable and if your ammo is properly loaded it will function fine. even if it's loaded a little hot it will still work and your rifle will still be fine. you can't say the same thing with a rifle that was head spaced with tape. and I still don't understand why it is so hard for people to wrap their head around.
You use a loading manual or get trusted data from powder manufactures sites?

Why not just throw caution to the wind and fill up the case with any ol powder.
why not?? cause you know it's not proper nor safe,

Do you use a kitchen scale to measure your powder or do you set up a precision balance or electronic scale and use that?

Thats the same reason to headspace gages. accurate, trusted, known and traceable

[ar15barrels]

Explain it; having the bolt stop 8.5mm short of closing. I'll admit I don't know how that happens with the correct gauge. Enlighten me.

It's NOT the bolt stopping 8.5mm short.
It is the bolt CARRIER stopping short.
This will happen regardless of the chamber being 0.001" or 0.020" short.
Basically, all we know is that the chamber is too short to close on the particular gauge.
Nothing else can be determined from measuring how far open a bolt carrier is when it stops on a gauge.

[ar15barrels]

Why? You can have perfect knowledge of how a brass case fits into a gun, or not, and then defend it to philistines like me! Once you understand the gun or the cartridge can be off spec, it's easy to understand. Unlike the gauge warriors...

Tape won't tell you if its the gun or the ammo.
A hornady comparator won't tell you if its the gun or the ammo that's off spec UNLESS you have a standard to calibrate your hornady comparator against.
We call those "standards" headspace gauges as those gauges are the "standards" that ammo and gun makers all work to.

[ar15barrels]

But...the guages take the rifle being out of spec off the table in a hurry...right???

Yes.

So...then YOU only have to worry about YOUR ammo being out of spec...right???

Correct.

[kcstott]

It's NOT the bolt stopping 8.5mm short.
It is the bolt CARRIER stopping short.
This will happen regardless of the chamber being 0.001" or 0.020" short.
Basically, all we know is that the chamber is too short to close on the particular gauge.
Nothing else can be determined from measuring how far open a bolt carrier is when it stops on a gauge.

I'm only stating this as some guys use this as a measure on a M1 Garand.

As they do measure how close the bolt is to closing. But with all the tolerances involved or lack there of. 8.5mm could be perfect on my gun, bad on another and way long somewhere else. like you said how far the carrier is from closing is nearly useless information.

That said the rifles I've checked are pretty much done rotating at 8mm from closing.
8mm from closing is also past the point where the lug on the rear of the bolt carrier prevents an out of battery ignition. so the bolt although unknown is pretty close to being fully closed.

[klewan]

Things are clearer now; you peeps that charge money to work on guns HAVE to use the gauges. Liability and all. Plus it's faster, and time is money. Your mindset fixates on the gun being in spec, that's what you have in your hands and not the ammo that will ultimately be used in it, since you don't have access to that ammo. So your industry is gun, gun, gun. If that's in spec, I'm off the hook for liability. Blows up on the first shot; bad ammo. It was in spec, not my problem...I used to wrench for a living, I remember how we could do things on our own cars that we could never do with a customer's.

But for the rest of us, there are workarounds we use. We have access to the ammo, so we can check it with the various workarounds, if the field gauge is giving .008"-010" slop over the no go, and I can check to .002"-.004" without much trouble, I know it's safe. After I've checked 4-5 ammo lots and all are about the same clearance, I'm pretty damn sure the headspace is within tolerance. But you industry guys can't do that. At least not on customer guns, your own, probably if you don't have the gauge. Like the Lassen college gunsmith that showed me the tape trick...

[kcstott]

Klewan
Your numbers are wrong
Spacing between gages and this depends on the caliber is .004" to .006"
And a field gage or demensions there of should never be used to determine a safe limit. It is the absolute ragged edge of safety.

Also no one should be trying to manipulate the case length to compensate for poor headspace.
That device you mentioned is for building match grade ammo not fixing an out of spec weapon.

As for us doing this for money and needing gages to be in spec for liability. Yeah that's one reason. But inevitably its you rifle, hands, and face at risk. If you feel comfortable using tape to head space you weapons go for it.
And you can also surface you brake drums and rotors beyond the service limit or just use a tape measure to check the thickness as that is good enough.

There are reasons why we have standards of practice. And it's not to protect you. It's to protect use from people like you.
Sorry but until you get that through your thick head you and everybody else that heads aces a rifle with tape is a danger to themselves and everybody around them.
This is not about being cheep or being anal, this is about doing something correct so that you can go home at the end of the day.

There is a reason you parachute needs to be pack by a master rigger or under the direct supervision there of.

[klewan]

Thanks for the reply KC, I've been comfortable doing it this way for 15 years, never had a problem. I'm within a couple of c*nt hairs, that's good enough. I've had my Mitutoyo Combi mikes for 40 years, when I need a couple of ten thousandths to measure, I can do it. Guns don't require that level of accuracy, at least the headspacing doesn't.

I did leave the rotors on my car alone, never turned them if the brake pedal wasn't jumping up and down from run out or a parallelism problem. Miked them to make sure I hadn't worn off a millimeter, just new pads every 18K miles. Couldn't do that with a customer car, they thought I was cheating them by not turning most of what was legal off the rotor. Then I got to sell them new rotors. I'm trying to save you money, dumb*ss, buy the rotors in 25K more miles...and I always test drove the car before I did any work. Found a lot of additional problems they were hoping I wouldn't notice and then claim 'It didn't do that before you worked on it!" So I understand what you guys in the biz are up against. Continue to recommend the 'factory' way, its the only safe way to protect yourself.

[ar15barrels]

Headspace Issue?

Spacing between gages and this depends on the caliber is .004" to .006"

223 gauge steps are 0.003" per gauge.
308 gauge steps are 0.004" per gauge.

[tujungatoes]

So I understand what you guys in the biz are up against. Continue to recommend the 'factory' way, its the only safe way to protect yourself.

I'm not in "the biz" and I still do it the "factory" correct way. ...Maybe I'm just overly fond of my fingers. And we all know the ladies can't resist a dude with an eye patch.

[valley82]

I'm not in "the biz" and I still do it the "factory" correct way. ...Maybe I'm just overly fond of my fingers. And we all know the ladies can't resist a dude with an eye patch.

LOL ^this.

[SJgunguy24]

I'm not in "the biz" and I still do it the "factory" correct way. ...Maybe I'm just overly fond of my fingers. And we all know the ladies can't resist a dude with an eye patch.

Maybe you just value your face more then the other guy. I mean really, what's 60$ out of pocket when compared to the awesome story of how you blew half your face off? Hey, you could always use that tape to apply direct pressure so you don't bleed out while waiting for EMS to arrive.
Or hey, wrap the receiver with that tape to give you an extra containment layer. You know so when that 50,000psi bomb goes off 6" from your face, that tape can catch any shrapnel and keep you safe.
60$ compared to your eyesight is cheap insurance.
I mean who wants to see? Eye sight is waaay over rated, just ask Stevie Wonder.

[kcstott]

Klewan
That statement right there explains to me just how little you understand what is needed in setting up and correcting headspace.

Your philosophy holds zero water as the majority of gun owners don't reload and there for will not pay any attention to their ammo
And you missed the point on the dial calipers,
But I fear all this is a waste of time for a guy that has a beat it to fit painting it to match mentality.

Oh BTW just because you've been doing it and getting away with it for 15 years don't make it right. It doesn't prove your concept.
That statement is the number one reason people continue to do stupid stuff

The brake rotor reference well again that shows how little you really know. Not once did you mention putting a dial indicator on it to measure runout out and put that on your estimate, then compare that to the published limit.
If a mechanic told me it's good I want to see numbers. I guess that's why I do all my one auto repair too as I have a near zero trust in auto mechanics as well.

As for being in the business. I'm not either. I've installed a few muzzle brakes. Welded a few bolt handles, made a few sets of rings and bases.
But I don't do any major work on guns like Randall and Ken does.

[klewan]

Glad all of you peeps are so concerned with my safety. Been riding motorcycles on the street for 43 years, so obviously I can't be too concerned with safety. Only hit the ground once in all that time; downhill, off camber turn on a new bike that I hadn't measured the headspace on....

I understand the vast majority aren't going to be able to understand headspace is just the gap between a closed bolt and the head of a cartridge firmly in contact with the chamber. But I'm not part of the vast majority of clueless mechanical midgets, the half and more of the population that are below average in mechanical reasoning. You guys are trying to make it seem there's only the factory way to do anything. And tunjo; go suck on it!

[valley82]

Klewan, I only speak for myself...if you want to "do it your way" and "there is no reason to do it the easy, accuated and safe way because it costs $60.00 to do so", I could care less. If you want to shoot 5.56 out of a.223 barrel till it grenades in your face because you have gotten away with it for years..again I do not care. As long as you don't stand next to me and do not send me the medical bills...your face your call.

But when you try to say that using tape is as accurate, or as repeatable as the guages it just blows me away, how can someone that prides himself as a mechanic go all redneck on this??? Adjustable wrenches, visegrips, bailing wire and duct tape...Yee haw.