Gas timing ?

[edgecrusher]

@candid, all your questions are theoretical and moot unless you are a bench rest shooter and strap your gun down and replicate the same exact outside factors on each trigger pull. If that’s the case buy a bolt gun that is far more consistent internally. The questions your asking are moot there too given the variance on each individual round of ammo. Last but not least, you are the biggest variable and until you can shoot consistently under .25 Moa i really do t think any of this matters other than being able to spout a bunch of loquacious words attempting to make yourself sound intelligent. This shit is way above my scope of knowledge and I don’t care, why? Because I don’t shoot that way. Closest I’ll ever get is shooting off a bipod. That changes variables every round. Shooting on the move. Again, more variables. I challenge myself to be consistent because there is no way I’m good enough to care about that mumbo-jumbo. I’ve never shot better than the One time a had a five round .375 Moa group. Once. Every other time I fuck up and I’m the variable. 

[Candid]

edgecrusher

I asked only two questions. and will paste them here again, along with my reason for asking.

"Are there  authoritative references on the gas and bolt timing for the AR -10/ Ar-15 type actions?

Is it all trial by error?

I would like to better understand the timing as the expansive gas opens the bolt. "

 

The rest, including accuracy and external ballistics, has been imposed by others reading into the original post their own agenda.  I'm not sure why that was done. 

Theoretical becomes very relevant when one tries something different.  It has not All been done before.

 

I read in this forum about a fellow that removed the sealing rings from the bolt in an effort to increase accuracy.  I thought that was crazy to try to connect those two.  The bullet has long left the muzzle by the TIME the sealing rings even start to move.  But....That is a subject that has differing viewpoints.  Perhaps there is something to it,  perhaps not.  I only bring that up in example,  Ring less bolt sealing is not my interest,  but I could see a simple labyrinth seal design effectively replacing the standard multi piece rings.

I appreciate the useful comments and literature references.  I've done more digging on the topic through them. 

regards

C

[Candid]

This work has a LOT of useful insight for any interested .  In general applications,  (not just gas timing;-)

https://archive.org/details/RifleAccuracyFactsFullV1.0FirstFullScan_201705

 

800 mb  it's a large file. 

[98Z5V]

1 hour ago, Candid said:

The rest, including accuracy and external ballistics, has been imposed by others reading into the original post their own agenda.  I'm not sure why that was done.

YOU drove that agenda, by yourself, and led the discussion in YOUR direction.  Let's get that shiit straight right now.

You know exactly why you were doing that, when you did it.  Don't try to fucking pawn this off on me or anyone else.  You felt like being a dickhead, so you were, and did.

[Candid]

That is your view.  My position was to continually return to the question placed in the original post.

You are welcome to show me my error. 

[98Z5V]

12 minutes ago, Candid said:

That is your view.  My position was to continually return to the question placed in the original post.

You are welcome to show me my error. 

Hey, fuk yourself.  I responded - I think I was the FIRST one to respond to you.  Enjoy your time here, you pompous jackass. 

Love ya - look forward to your contributions here.   ❤️

Maybe you should RESEARCH what you're looking for, instead of blaming people HERE for not getting you the direct information that you DEMANDED from this board.  Research that bullshiit that you're looking for, on your own.  Maybe when you find your mystical answers from somewhere - come back here and tell us all the shiit you found, that doesn't really matter anyway.  How about THAT...  Put some fucking work in, and stop blaming this board for the bullshiit that you seek.  Chomp on that for dinner, and for desert, choke on a bowl of smashed assholes.  

Edited November 1, 2020 by 98Z5V

[98Z5V]

If you want to get into some kind of a direct challenge, directly with me, then you bring it.  I'll welcome it. 

Otherwise, you're just off your leash on this board, running your cock-holster. Thinking you can do whatever you want to do.  I'll reign your ass in, you bet on that.

Edited November 1, 2020 by 98Z5V

[Thirstydg323]

14 minutes ago, 98Z5V said:

If you want to get into some kind of a direct challenge, directly with me, then you bring it.  I'll welcome it. 

Ego 

[98Z5V]

3 minutes ago, Thirstydg323 said:

Ego 

Nope.  Experience.  Good try, though.

Proficiency breeds confidence.  Mistakes equal learning, and experience.  I've done that.

Go back, before you bark here, and look at this whole thread.  Then, you bring your pain.

Nice first post, by the way.  You're more than welcome to get into the Intro Section and tell us ALL ABOUT yourself. 

We'll all welcome that, too. 

Edited November 1, 2020 by 98Z5V

[Candid]

I don't get where you are coming from.

I've blamed no one for anything.

 

A question posed is research.

[98Z5V]

@Candid - you're here now, reading this thread...  lurking... doing whatever you do...

I'll wait for your reply... 

 

[Candid]

reading? 

[98Z5V]

14 minutes ago, Candid said:

I don't get where you are coming from.

I've blamed no one for anything.

 

A question posed is research.

Then get your ass up on your research, find out what you're really looking for out there on the World Wide Web - FIND what you asked, and post back here with the results.

The clock is ticking.  This is almost like a challenge, here - but the clock is ticking on YOU.  GO FIND your information - after the complete shiit-storm that you created here...  and POST YOUR FINDINGS.

I'll wait... 

Oh, good luck, too...  I hope you FIND this unicorn that you BLAMED us for not knowing about...    

I'm all ears, here.

Edited November 1, 2020 by 98Z5V

[98Z5V]

On 10/28/2020 at 10:24 PM, Candid said:

Are there  authoritative references on the gas and bolt timing for the AR -10/ Ar-15 type actions?

Is it all trial by error?

I would like to better understand the timing as the expansive gas opens the bolt. 

Rifle length, mid length. carbine length pistol length,  they all are able to work,  How?

Gas travels at the sonic limit , and is a function of temperature.  These "details" are of interest.

 

On 10/29/2020 at 6:44 PM, Candid said:

This is good enough

http://ar15barrels.com/prod/operation.shtml

 

On 10/29/2020 at 8:24 PM, 98Z5V said:

To a certain degree, yes, it's trial and error, especially for the different calibers that we all love.  For certain calibers, it's experience, but it can be calculated to a range, and it'll work within that range, for sure.  Gas Systems and Recoil Systems are tied in together, and there's no way in the world that anyone can refute that fact. 

They're all able to work, because of gas port diameter in the barrel.  It goes way deeper than that, per gas-tube-length, though. 

Your later question, in red, would have been better asked first.  Then it would make more sense.  Read your red question first, and my answer - then read your orange question next, then my answer...  

What you're talking about is a Can Of Worms that I opened up here a very long time ago.  I've written about it, as best I can, in detail, here.

^^^  That shiitstorm right there is the very beginning of this thread.  You can't refute that, not even a little.  Unless reading comprehension is a problem for you.

[98Z5V]

I think I even corrected you early on, when you stated that the gas was a function of temperature - and I corrected that, and stated that these guns operate on gas PRESSURE.

GAS TEMPERATURE doesn't have a fucking thing at all to do with how these guns operate, as far as the cyclic operation. 

Now, go on here, and fuk with me, and tell me about Alaska, and Iraq, and -50, and +130. I dare you.  That doesn't have ANYTHING to do with the beloved "gas temperature" gnome that you're trying to figure out here.  Which is a non-event.

Bring it @Candid

Edited November 1, 2020 by 98Z5V

[Candid]

98Z5V

 

Curious,  the bottom panel of your previous quote has nothing to do with anything I wrote.  You may be confusing my posts with those of another member.

 

For clarity,  When I speak of temperature dependence of gas velocity,  it is NOT ambient temperature.  rather it is the 5000-6000 degree temperatures associated with powder combustion. 

Imagine a wall of hot gasses pushing a column of cold air down an 1/8th inch tube.  'Must take time to crowd all those molecular cats into a hole like that.

[98Z5V]

2 minutes ago, Candid said:

98Z5V

 

Curious,  the bottom panel of your previous quote has nothing to do with anything I wrote.  You may be confusing my posts with those of another member.

Go fuk yourself - I directly quoted you, and it's all here in the first page on this thread. 

 

3 minutes ago, Candid said:

For clarity,  When I speak of temperature dependence of gas velocity,  it is NOT ambient temperature.  rather it is the 5000-6000 degree temperatures associated with powder combustion. 

Then, as I stated earlier - you better get your ass out there on the WWW, and find someone that can "bond" with you on the bullshiit that you're trying to learn - and you need to STOP blaming members here for the made-up thing that you're trying to learn, and ask about - and attack people here for not knowing WTF imaginary thing it is that you're DEMANDING information on.

You get that part, right?  You came here DEMANDING information.  And - you can fuk yourself.  Don't come here and DEMAND information from people.  We worked hard for the information that we've found out, over the years, but that doesn't mean that you have a right to it. I worked for the information that I've found out - I'll SELL it to you.  I WORKED for it.  Depending on how bad you're DEMANDING it, determines the price.  You want it RIGHT NOW!!!

Fuk, that's expensive. 

You want it next week?

My weeks are busy, but I'll TRY to get to it...  That costs a little less...

You get pissed off, because I told you I'd try to get to it next week, and I was overwhelmed with work - and then YOU TURN INTO A DICKHEAD?!!? 

The price just tripled.  Because I don't HAVE to deal with you. I didn't come to YOU.  It was the other way around.

You, @Candid - need to go way back to your very first post, read what you posted, and read the initial reponses.  THEN, you need to figure out, WHERE in this thread, that you turned into a complete dickhead. 

[Candid]

Not to worry

What was asked in the original post has been presented buy Lane's reference document.

I found a reasonable discussion about the gas system. From the U.S. Army Aberdeen Research and Development Center Ballistic Research Laboratories. I haven't read it cover to cover; but it does appear to cover all of the math required to figure out those parameters. 

https://apps.dtic.mil/dtic/tr/fulltext/u2/704342.pdf

 

[end quote]

 

Thanks Lane!

[Candid]

18 minutes ago, 98Z5V said:

Go fuk yourself - I directly quoted you, and it's all here in the first page on this thread. 

 

Then, as I stated earlier - you better get your ass out there on the WWW, and find someone that can "bond" with you on the bullshiit that you're trying to learn - and you need to STOP blaming members here for the made-up thing that you're trying to learn, and ask about - and attack people here for not knowing WTF imaginary thing it is that you're DEMANDING information on.

You get that part, right?  You came here DEMANDING information.  And - you can fuk yourself.  Don't come here and DEMAND information from people.  We worked hard for the information that we've found out, over the years, but that doesn't mean that you have a right to it. I worked for the information that I've found out - I'll SELL it to you.  I WORKED for it.  Depending on how bad you're DEMANDING it, determines the price.  You want it RIGHT NOW!!!

Fuk, that's expensive. 

You want it next week?

My weeks are busy, but I'll TRY to get to it...  That costs a little less...

You get pissed off, because I told you I'd try to get to it next week, and I was overwhelmed with work - and then YOU TURN INTO A DICKHEAD?!!? 

The price just tripled.  Because I don't HAVE to deal with you. I didn't come to YOU.  It was the other way around.

You, @Candid - need to go way back to your very first post, read what you posted, and read the initial reponses.  THEN, you need to figure out, WHERE in this thread, that you turned into a complete dickhead. 

I was under the impression this was an interest topic forum open to 308 AR types  and firearms in general,  along with "other interests"  including motorbikes. and even bicycles  .  Perhaps I was wrong..... 

Would you please describe the intent of this forum so that I no longer hold misconceptions? 

[Candid]

Just to be clear,  I enjoy firearms for my own pleasure.  Constructing, modification in the shop as well as range time at the club are all part of the enjoyment.

I "stumbled" upon this forum and read many topic posts in that I have built a pair of 308s  to my own liking,  and am always interested in what others are doing.

I have little interest in some aspects of shooting,  generally where competition with others is involved.  Competition with others with firearms means someone doesn't leave the field.

But I enjoy a couple hours poking 50 holes in the NRA small bore 50 foot target placed at the 50 yard berm using peeps.    Call it "personal best"  .

It's about all we can do...  society and social pressure is closing in.

I'm past the time when I care what other people think about what I say or do

 

Hey 98V5z    Go fuc^ yourself!    No offense

[Lane]

LOL. I stepped away for a few minutes, and it tuns into that?!?!  @##@$%^%&?    ^^^^^^ 

There's another document mentioned at the end of that which I've not bothered to find yet: M. Werner, "Analysis of the Gas System of the M-16 Rifle," to be published as a Ballistic Research Laboratories Technical Note...

There's quite a bit I could say after reading through report #1475; but I'll keep that to myself for now. Generally speaking (based on that research); I doubt anyone would be able to make up a useful calculator for port size, gas tube length, BCG weight, buffer weight, receiver extension depth, and spring constant; given the findings of that document. Variances for friction were so high; that even the researchers involved refused to validate their own approaches. In reality; trial and error appears to be the fastest way to those ends. 

One could probably make a more calculated effort on one particular firearm by taking some measurements of how the physical system is operating up front, to fill in some of those gaps. not sure that would be at all worthwhile without (at the very least), a PressureTrace on hand. https://www.shootingsoftware.com/pressure.htm 

[Lane]

12 hours ago, Candid said:

In general applications,  (not just gas timing;-) 800 mb  it's a large file. 

I know... That pdf can be compressed or converted for use on slower devices like phones, and eInk tablets. It is nice to see original documents scanned.

That "other" information wasn't linked for no reason at all. There needs to be at least some basis for jumping that deep into the gas system up front. Almost everything else matters before the gas system. The graphs on the pressure trace information page should provide a few clues about why that is.

Look at this. The implementation of the internal microphones inside the LabRadar unit. Designed to listen to gunshots; it's really quite dumb... Any old cheap a$$ mic element can be tamed to work for a gun; but almost nothing works out of the box (without reducing the input gain). It's trivial to record the action of your own firearm.

On the other hand. You might as well start recording the temperatures along the outside of the gas tube. And what about the twist due to temperature changes (that's a regular physics lab experiment one should have seen during primary education)?

Int-Photos-2503420.pdf

[Radioactive]

16 hours ago, Thirstydg323 said:

Ego 

Nice first post.

[98Z5V]

20 hours ago, Candid said:

Competition with others with firearms means someone doesn't leave the field.
 

Please explain your background, for making such a statement.