Impact/Proof prefit torqued to spec is closing on the no go gauge. I have never used these gauges before. On the go gauge it closed effortlessly. On the no go gauge it closes but it takes a lot (comparatively) of force. Is this acceptable?
- Thread starter ThatGuy01
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Your not supposed to force a bolt closed on a gauge, could damage the gauge and isn't doing your action any good. If you feel any resistance on a no go gauge that means your action doesn't want to close on it and your chamber is good if it closes on a go gauge with no resistance
Yes. If you're forcing a NO-GO you can damage the gage.
Learn what the gages are supposed to do.
Your action should absolutely NOT close on a FIELD gage -- EVER. If it does your headspace is unsafe and you could damage your action and maim, blind, or kill yourself.
Learn what the gages are supposed to do.
Your action should absolutely NOT close on a FIELD gage -- EVER. If it does your headspace is unsafe and you could damage your action and maim, blind, or kill yourself.
If it takes a lot of effort to close on a *no go* gauge, the chamber is likely fine. Go/No Go gauges are general in the middle of specs, not on the min or max allowed measurements.
But the best thing to do is get a *field* gauge and check. If it still closes, you have a problem. Though field gauges have become less and less common. So you may or may not be able to find one.
The best thing is take it to a competent gunsmith and let them take a look.
But the best thing to do is get a *field* gauge and check. If it still closes, you have a problem. Though field gauges have become less and less common. So you may or may not be able to find one.
The best thing is take it to a competent gunsmith and let them take a look.
Out of curiosity, what is your barrel chambered in, which brand of gauge are you using and is the "No-Go" gauge marked with a dimension?
Can you explain how long headspace results in explosions?
6.5 CM. Not sure about the gauges. I borrowed them and gave them back. I can try to find out though.
Long headspace can allow case head separations or cracks in brass. Anytime there is gas leakage there is a chance that other things can happen. Normally not much happens except needing to get the case without a head out of the barrel.
However, the real danger comes with the next shot. If there's any pieces of brass and such in chamber/barrel, or worst case there's a squib in the barrel......and we don't notice....the next shot can definitely make boom boom.
Headspace allows the entire cartridge to move forward and backward within the chamber. You will read many who say to only push the shoulder back 0.002" when resizing. Effectively, that cartridge is only able to move fore and aft those 0.002". This is the measurement I adhere to.
When the striker (firing pin) hits the primer, it pushes the cartridge forward as far as it can go. The impact of the striker ignites the primer charge which ignites the main charge which starts pushing the bullet forward. As the bullet starts to move towards the muzzle, the case is pushed back to the bolt face. Newtonian physics and shit. Once the bullet bearing surface clears the case mouth (and even before), the hot gasses created by that burning powder also escape around the bullet. Some head down the barrel ahead of the bullet and some escape back down around the casing toward the bolt face. It's an explosion finding the path of least resistance.
Ideally, the case has a proper amount of headspace. If so, the brass will be pushed against the bolt face right away and there is no place for the hot gas (pressure) to go but radially against the case walls into the chamber and outward towards the muzzle. The soft brass expands to the chamber and creates a good seal forcing the remaining pressure out the bore of the barrel. Pretty much, even on tight necked chambered rifles, the neck of the case will be black from having some hot gas burning against it prior to that good seal.
In the case of too much headspace, the seal is not created soon enough allowing a bit of space to be maintained or even increased during that main charge burn. Brass is soft. With nothing to support it (the chamber), it separates. Sometimes this leads to other failures. I have seen photos of cases that were pretty much just collapsed due to that pressure. I have a case that has a strange bunch of dimples all around the shoulder. I know that gasses (excess pressure?) did that but I don't know how or why because it was exactly like all the others (I think). Other photos of cases split along the length. Still others where there was a catastrophic failure of the bolt and action. Usually, when this happens, folks blame an excess powder charge when it was really just resizing too much or a chamber out of spec.
I've often wondered if necks will expand a very large amount, or if it's actually the shoulder sealing that is the main driving force on sealing chamber.
For example, there's plenty out there who using something like an IDOD to turn necks in standard chambers. Without any issue. I've run plenty of 0.011 walled brass in 6mm's with .273 and .274 necks. So that's .008-.009 clearance. And know others who have experimented with even more clearance. The general consensus bing that a neck too tight can be bad, but other than possibly splitting necks sooner than normal, there's almost no such thing as too much clearance.
So, I've wondered, does the neck still expand and seal .008 or more clearance......or does the shoulder do most of the sealing.
Oh, and you did remove the striker/firing pin, cocking assembly/bolt shroud and firing pin spring from the bolt before you started reefing on everything, right ? 
Lol. That’s a fair response. In my defense I did try to watch some after the fact and there is not a lot of good info about issues with no go gauges.Maybe watch a couple YouTube videos first...
This isn’t necessary if just checking a barrel with gauges. Slide the gauge under the extractor and go with it.Oh, and you did remove the striker/firing pin, cocking assembly/bolt shroud and firing pin spring from the bolt before you started reefing on everything, right ?
The above is correct. You will get no different results with the bolt stripped or not. As we aren't looking for any feedback on the forward motion or rotation of the bolt, just whether or not it will close.
Yeah, that was sort of the point of me saying that bit about the necks being blacked. The neck doesn't perform the main seal. When I went and re-read what I wrote, I see that I wasn't real clear. The neck/shoulder junction provides a place to index, if you will, and provides the primary seal. PO Ackley stuff is created because of this seal.
I think all this is long time myth. We fireform using excessive headspace all the time when we make Dasher brass from BR. Not Ackley fireform, straight up shoulders don't touch the front of the chamber. I think people have conflated excessive bolt nose clearance resulting in an unsupported case that ruptures and blows out the action with the effects of long headspace. Obviously we haven't stated "how excessive" in the examples we're talking about, but 2 thou of extra because the bolt can barely clear a gauge is inside of many amateur reloaders that don't know how to set a sizing die up and end up accidentally or unknowingly bumping the shoulders 8 thou instead of 2 thou. That shit will stretch out. It won't blow your face off. Total melodrama. In reality it doesn't matter if you have long headspace, if you reload, and you set your die accordingly. All you need to do is set your shoulder bump correctly. The opponent to this argument will obviously cite factory ammo, but again: your either leaving the brass lie on the ground or you're reloading it and if you are....set the shoulder bump correctly.
Stretching a few thou one time won't blow your face off or cause case head separation.
You are correct, to a point. My comments above relate to a full power, normal, charge. I use a full power charges when making 223 Ackley cases because I do have that seal at the neck/shoulder junction.
Generally, when fire forming in the direction to which you refer, folks jam a bullet into the lands and use a reduced powder charge.
How do you form your Dasher brass?
I've jammed, made false shoulders, and hydro-formed. I have gotten collapsed cases when jamming. Guess what I still have? My original OEM face. Because the web still seals. That's where your premise misses a crucial detail.
This exploding headspace thing is prudent to say to a beginner so he sits up and takes notice of it being a serious thing to consider. But it's prudent in the same way pharma companies put a litany of potential side affects on labels. If it was even remotely possible to have those side effects it would be a fate worse than death. But we all read it, shrug our shoulders, and take the Viagra anyway.
Another thing to consider is everyone hyper fixates on checking headspace on prefits or new guns but they never check factory ammo. I've seen virgin brass that was .008" short from once fired. The allowable variations are a little more resilient than a chamber that is three thou long in head space will cause an explosion outside the chamber. A SAAMI headspace number is a reference number because what really matters is the relationship between your brass and the chamber, not as much the gauge. And not all gauges are made correctly.
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At the shoulder or at the case mouth?
What would you say is the primary cause of casing failures like split along the length, crushed shoulders/cases, complete head separation, catastrophic failure of bolt/action?
Super broad, vague, what's the context, multiple scenarios, etc.
Yes, headspace.
Now, to be clear, I need to understand how the case web seals the pressure. Please explain.
Please explain how that could happen.
What is the best method? Why jam? I can understand the false shoulder. Have you hydro-formed going Br to Dasher?
Where is headspace measured? What determines the headspace dimension of a given cartridge? Why is headspace even a concern?
Can you explain how long headspace does not result in explosions?
What is this a DNS attack? Victory by volume? We've already established a gun isn't going to blow up from a couple thou long headspace and used Dasher fireforming as a case example to demonstrate it by a common method. Now you're trying to quibble about split necks? And trying to reverse burden of proof by asking me to Bill By Science Guy explain shit?
I'm over it. I think we all know a person won't be maimed, lose eyesight or limb, or life because a bolt barely closes on a no go gauge.
Who wants to discuss exterior ballistics with a guy who knows everything already?
Please make heads or tails of this? What is he trying to say? https://www.snipershide.com/shooting/threads/ukrainian-sniper-shoots-russian-from-1-68-miles-away-%E2%80%93-the-second-longest-kill-ever.7148015/page-3#post-11232143
www.snipershide.com You asked, were provided an answer that can be documented from MANY sources. Then you argued. You were then asked to substantiate your position.
So...you are unable to provide any substantive reasoning. Got it.
It was a rhetorical question. Not one of curiosity. Explain how 3 thou long headspace will explode a rifle. That was my contention. You couldn't. Then you tried to change the goal posts and reverse the dynamic. I refuse to go down your rabbit holes. It's that simple.
Again....
Explains how long headspace could explode a rifle. Remember, you asked.
Go ahead. Give it a go.
See...I am not the one trying to change anything at all.
Please, do make an effort. Be ready to support. You know, because, trust me bro ain't gonna cut it.
JFC dude. You're asking really basic questions like it's proof of something. Like you think you're trying to draw me out to pounce with your superior technical expertise.
Have I hydro formed. Yes. Didn't I say I hydro formed? Yes, I did. Why TF are you asking again?
What's the best method? Eye of the beholder. Hydro forming is mess. Split necks and bodies, headspace is all over the place and variable. Requires resizing after to control it to some modicum of relation to the chamber. False shoulder is extra work to accomplish the same thing as jamming. Jamming, imo is the best method as long as you can be happy with running a BR load for a few hundred rounds. I get less split necks and crushed cases doing this. About 2 per hundred. Just requires about 8 thou neck tension and still results in accurate loads at BR speeds.
Why doesn't headspace result in explosions? @Rio Precision Gunworks explained it for everyone. The case body stretches.
WOW! Breaking news! Like noone knows this?!! Do you think you're paving the way with this question to make a point about casehead seperations? Yes. If you repeatedly over size a case and bump the shoulders to much, you can have casehead seperation. But not by 2 thou short....once. like I have already said: set your die to bump properly. WTF do you think you're proving by dragging this out?
Lol, you just edited your post.
Okay, Bryan Litz....how excessive does the headspace have to be to blow a gun up? 2 thou? 12 thou? 20 thou?
You keep ignoring the concept of fireforming proves my point. It's not "trust me". I'm proving it through a demonstrable and common practice.
You're confusing me challenging someone on some old myth that a couple of thou of headspace will blow a rifle up with me saying headspace doesn't matter. I think we all get the occasional case that's a couple of thou too short when setting up a die. Or headspace a barrel based on piece of brass with two layers of Scotch tape because gauges aren't available. Let's not get melodramatic and pretend that guns blow up from these things.
JFC dude. You're asking really basic questions like it's proof of something. Like you think you're trying to draw me out to pounce with your superior technical expertise.
Have I hydro formed. Yes. Didn't I say I hydro formed? Yes, I did. Why TF are you asking again?
What's the best method? Eye of the beholder. Hydro forming is mess. Split necks and bodies, headspace is all over the place and variable. Requires resizing after to control it to some modicum of relation to the chamber. False shoulder is extra work to accomplish the same thing as jamming. Jamming, imo is the best method as long as you can be happy with running a BR load for a few hundred rounds. I get less split necks and crushed cases doing this. About 2 per hundred. Just requires about 8 thou neck tension and still results in accurate loads at BR speeds.
Why doesn't headspace result in explosions? @Rio Precision Gunworks explained it for everyone. The case body stretches.
WTF do you think you're proving by dragging this out?
I now refer you to my post in this thread (post 13):
Who wants to discuss exterior ballistics with a guy who knows everything already?
Please make heads or tails of this? What is he trying to say? https://www.snipershide.com/shooting/threads/ukrainian-sniper-shoots-russian-from-1-68-miles-away-%E2%80%93-the-second-longest-kill-ever.7148015/page-3#post-11232143
www.snipershide.com Two pieces of scotch tape ? Damn, that's living on the edge . I have only dared to go with one .
That's ridiculous. What do you think .002-3 thou bump is?
Not today ISIS. If you can't summarize, I'm not going to waste my timeI now refer you to my post in this thread (post 13):
Who wants to discuss exterior ballistics with a guy who knows everything already?
Please make heads or tails of this? What is he trying to say? https://www.snipershide.com/shooting/threads/ukrainian-sniper-shoots-russian-from-1-68-miles-away-%E2%80%93-the-second-longest-kill-ever.7148015/page-3#post-11232143
Headspace by definition is range. So how can 0 headspace be the only right answer? Most reloaders can't bump a shoulder to .001 thou every time, 100 cases in a row.
Ugghh, so exhausting.
So I said .002 - .003 and your reply was "excessive". Hence you think .002 is excessive. The range of a go and no go is .004. that's the range. So .002 is inside the range. Not 0. But now you're trying to cover your tracks with a vague "excessive".
Like I said in my first reply to you. You're confusing me challenging someone with the idea that a couple thou long headspace will blow up a gun with me saying headspace doesn't matter. Let's not be melodramatic and pretend that someone is going to blow themselves up by having a case that's.002 outside the range. Or do you contend that a fun will blow up from .002 outside the range?
People do one of two things when they're proven wrong. They shut the fuck up or they devolve the argument into ancillary points that are off the original point. Here you go ... quibbling over some verbiage.
You pretty much, tacitly agreed that excessive headspace won't create an explosion when you replied with your post about "how much is safe", "why risk it?", "for what purpose". That should've been it right there. My original and consistent premise is that excessive headspace won't blow up a gun. My example of proof is fireforming Dasher brass. No one has refuted that for good reason. People do it all the time. It demonstrates my point. You like Aftermath tried to devolve the argument to key adverbs to "proof by grammar ". To be right about some minor point. Split necks. How headspace is measured. Why take risks. How do webs expand? Blah, blah, blah.
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That is precisely correct. He asked how long headspace could cause explosions then wanted say that he meant 3 thousandths. He wants to argue and when you point out a flaw, he wants to say something different. He is unable to articulate intelligently, unable to provide objective data, does not understand why a case might collapse when jamming for fireforming and can't explain why you jam if you use that method. Again, post 13. Don't waste your energy on dipshits.
Are you trying to gather the Snipers Hide gang up crowd. Is that your method for refuting the premise that a little excessive headspace won't blow a gun up? Trying to gather some allies to speak in 3rd person like you're above it? You dickwads are the people that believed Theis was who he said he was. You guys create a status on this forum from posts. And you confuse that with thinking you're right.
This got heated real fast....whoa...I will just quietly go back to fireforming factory Lapua 6mm BR ammo in my Proof prefit Dasher barrel that just so happens to be really accurate by itself and hope the gentlemen can work things out...
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