Good Info On Correct Use of Fillers - Thank You Larry Gibson!

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Ed Harris posted this 2 weeks ago

The-proper-use-of-fillers

Good discussion if you haven't been over there.  Thanks to Larry.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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Scearcy posted this 2 weeks ago

Larry/Ed

That is a great discussion of the use of fillers. One question though - does any of this change significantly in a much smaller bore like 6MM or .224?

Jim

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Ed Harris posted this 2 weeks ago

I'm not the right guy to ask that question. 

I would defer that to John Alexander or another of the guys who works with the smaller bores. 

My educated guess is that the generalities would probably hold true, but in the smaller bore less filler is needed.

Anybody with hands-on knowledge of this PLEASE step in!

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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Ed Harris posted this 2 weeks ago

I expect we have a good many new forum users here who left "The Other" forum for whatever reason.

As long as people act like adults and play well with others all are welcome here.

 

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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onondaga posted this 2 weeks ago

I still use BPI Original Filler for the reasons I discuss and describe in my method in the post.

Gary

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OU812 posted this 2 weeks ago

I have read that used dried coffee granules can be used. Measured and thrown from powder dispenser.

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JeffinNZ posted this 2 weeks ago

My Carcano goes very well with 25gr H4350 topped with 9gr of BPI buffer and either a 140 or 170gr bullet with a crimp. 

Cheers from New Zealand

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John Alexander posted this 2 weeks ago

I would like to read the discussion. Where is it?

John

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Ed Harris posted this 2 weeks ago

Click on the hyperlink on my first post - if that doesn't work for you, here is Larry's post over there which started the discussion:

 

I have for many, many years found dacron (polyester fill) to be the best "filler". I use a filler only when appropriate. Many think I always use a filler with every powder....I DO NOT!!!! The use of the filler can cause problems if not used correctly and when appropriate. If the powder is not correct for the bullet/cartridge combination then the filler is not going to make it "right". Many want to use a specific powder for a cartridge because the powder is "cheap" or because "they have a lot of it". There are lots of powders that are not only poor choices to use but that can be dangerous if used in an inappropriate bullet/cartridge combination. Do yourself a favor if you are wanting to use an inappropriate powder (usually "no data" available is an indication the powder might be inappropriate) and get an appropriate powder. You will save yourself a lot of frustration. The use of the dacron filler only makes an appropriate powder perform better. The dacron filler will not make a silk purse out of a sow's ear.

I don't use the dacron filler or a wad with the fast to medium burning "fast" pistol /shotgun type powders. I find one of these fast burning powders that is fast enough to ignite and burn efficiently at the velocity I want and avoid using a filler with them. 

I almost always use the dacron filler in rifle cases with the slower “fast” burning powders (4227, 4759, 5744, 4198, etc. with lighter medium weight bullets for the cartridge; i.e. 140 - 165 gr bullets in .30/.31 cals of 30-30 through '06 case capacity), the medium burning powders (RL7, 3031, 4895, etc.) up through the slow burning powders (RL19, AA4350, H4831SC, RL22, 3100, etc.) that give around 80% or less loading density under medium to heavy weight bullets for the cartridge; i.e. 170 - 220+ gr bullets in .30/.31 cals. Those examples are for the .30/.31 cals but the same guidance applies to other calibers. The dacron filler is used only between the powder and base of the bullet. 

The “dacron” is polyester fill as commonly found in pillows and toys. It also comes in sheets called “batting”. It can be obtained very reasonably at most any fabric store.

The dacron batting comes in various thicknesses. I prefer that which is about 5/8" thick. My wife recently bought me 10 yards which will give many, many thousands of cast bullet loads. With this current batch of batting I cut it initially across the width into strips about 3/4" wide. I then "eyeball" cut 1/2" wide chunks which is close to 3/4 gr. 

A smaller chunk is cut for 1/2 gr and larger for a larger amount. I've cut some chunks that weight 1/2, 3/4, 1, 1 1/4 and 1 1/2 grs and have them in a "snack" baggie stuck on a poster board above my loading bench for quick reference when I need to cut new chunks. The batting will run thin and thick throughout the sheet so I again just "eyeball it" based on the thickness of the batting when cutting the chunks. 

Pretty extensive tests have demonstrated that the weight of the filler does not have to be exact, only close. What is important is that there is enough so that it “fills" the space between powder and bullet. A little too much hurts nothing but too little poses problems. That's why I have the different size "chunks" so I can use the right size for the case capacity I am filling. For example; with most medium burning powders (3031, 4895, 4064) in and '06 to function an M1 a 3/4 gr dacron filler is about right. With slower powders that give a higher loading density like 4831 a 1/2 gr filler is about right. 

I use a section of .22 cal cleaning rod in cartridges of .30 - .375 cal to push the Dacron chunk inside the case just so it is all in. The 6 to 10" section gives plenty to hold onto and sufficient "feel". Merely hold the chunk of dacron over the case mouth and shove it in with the rod. Sometimes it takes a couple three pokes to ensure all is inside the case mouth. I poke the chunks in until all the dacron is at the bottom of the neck or at least all in the case. It doesn’t matter exactly where just so long as you don’t tamp it down on the powder as a wad and leaved a space between the base of the bullet and the dacron. 

What you want to do is push it in to let the base of the bullet finish pushing it down and adding any compression against the powder. Thus I do not push it down on the powder but let the bullet do that when the bullet is seated. Using the right size chunk of dacron this method then provides a "filler" in the air space between the powder and base of the bullet. 

A small length of coat hanger works for the .22-7mm cartridges and an unsharpened pencil works well for .45 cals. With the charged cases in a loading block I simply hold the chunk of dacron over the case mouth and push it in with the rod. It is quite easy and a lot of “precision is not required, just get the dacron into the case and let the bullet finish pushing it down.

Larry Gibson

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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John Alexander posted this 2 weeks ago

Thanks Ed.  I didn't notice the hyperlink.

John

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John Alexander posted this 2 weeks ago

In the latest (July 2018) Shooting Times, former Speer ballistician Allan Jones discusses fillers for reduced loads.  Although the method of filler he mostly speaks of is something he calls puff balls (a wad of dacron or other fluff) pushed down on the powder as opposed the Larry's method of filler involves "filling" the space between powder and bullet with the fluff under some compression and Gary's method involved granular filler.

However, he reports lots of chamber ringing which Larry and Gary apparently avoid.

It would be nice to have a very clear description of what kind of filler might cause chamber ringing because one person's "filling the space" might be another's "wad of dacron." At least shooters should be aware that using fillers in certain ways can lead to chamber ringing.  Is avoiding air space between the filler and base of the bullet what avoids ringing chambers?  I seem to remember that Ed Harris mentioned trouble with chamber ringing at some time.

I would also like to hear more evidence of the need for fillers based on shooting trials. I could never get any improvement out of them but if others get improvements in accuracy, maybe i should reconsider not using them for the last 25 years -- anything to beat those misguided 30 caliber competitors.

John

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Ed Harris posted this 2 weeks ago

I did LOTS of testing with fillers when I was at Ruger, because a great many .45-70 rifles were received in customer service with ringed chambers, many rifles with multiple rings which corresponded to the base location of different weight bullets.

Using dense powders like #2400 and pushing a "puff ball" down tight on the powder I could ring a .45-70 chamber predictably.  It seldom occurred on the first shot, but would be obvious within a box or so of ammo.  Pushing a puff ball down onto the powder is never a good idea because the wad becomes a projectile and the bullet base a bore obstruction.  This condition was most pronounced in straight-walled cases, but could be reproduced also in bottlenecked cases like the .30-'06 if the bullet base was well up in the neck, as it normally would be with a 150-170 grain cast load seated out to contact the rifling.

The loose, fluffy method, using the minimum fiber needed to achieve ballistic uniformity, in which no visible "fluff" can be seen ejected from the muzzle is correct.

Normally I shun fillers and would prefer a powder which gives good ballistic uniformity without it.  However, in loading for the Garand in .30-'06 loading a fluffy filler reduces velocity variation which would otherwise take place given variations in powder position.  While slow-fire stages permit orienting the powder to the rear of the case, semi-auto operation forcibly positions the charge forward, and grouping is absolutely improved by use of filler in the Garand, which I consider a very specialized case where fillers are desirable.

 

 

 

 

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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R. Dupraz posted this 1 weeks ago

ED:

I have personally seen the exact condition of chamber ringing that you describe in an 1874 Shiloh Sharps 45-70. This rifle had been owned by a deceased club member and was purchased on his estate sale by another club member. The new owner noticed some resistance when extracting a fired case and on closer inspection, could see rings in the chamber. So the rifle was sent back to Shiloh for a rebarrel.

When the rifle was returned, included was a short section of the breach of the original barrel that had been milled in half revealing two clearly visible rings in the chamber right where the base of a bullet would have been. Now it was unknown of course what the first owner had used for loads or what had caused the rings, black or smokeless. But this club is exclusively black and lead bullets as far as any organized BPCR shooting go's. 

I have never used any kind of filler and never will. Preferring to experiment with different powders to find acceptable results.

 

R.    

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lotech posted this 1 weeks ago

I don't use fillers, but won't criticize those that do because many of them have put much effort into research and work that validly supports their conclusions. However, it seems that finding and using the most appropriate powder would negate any need for a filler. Is that an incorrect assumption?   

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joeb33050 posted this 1 weeks ago

Wayne?? of R.I., a CBA founder,  shot at Old Colony in the 80's; we argued about fillers, he was con, I was pro-strongly.

I stuffed pounds of dacron onto powder. Slowly I moved away, now it's years-decades-since I used fillers regularly. Wayne?? was right.

joe b. 

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Larry Gibson posted this 1 weeks ago

I am offering this as information/explanation only, I am not trying to convince anyone to use a filler or to not use a filler.

We see here in this discussion, as usual with this topic, that the use of a "wad"  in cast bullet loads has/is being lumped in with the meaning of what the word "filler" means.  There is a distinct difference between the two.  John Alexander and Ed Harris describe the difference in their posts.  Keep in mind I do not recommend the use of a wad of any material.  I only recommend the use of Dacron, kapok and the poly fillers (such as "original", Pufflon and GREX) be used as fillers given certain criteria.  That is specified in my post on another forum which Ed has reposted here. 

I do not always use a filler. I shoot many loads (more than with a filler actually) using appropriate powders that do not need a filler to ignite and burn efficiently and consistently.  When to use a filler (I prefer Dacron) is dictated by the powder's burn rate, the load density, the weight of the bullet and the desired velocity level. 

I do not use other fillers (coffee, COW, other cereals or other inert or organic materials) because my pressure testing of many have revealed inconsistent and some times dangerous levels of pressure are produced.

I do not use, nor recommend, the use of a wad of any material to hold the powder, especially the faster burning pistol and shotgun powders, back against the primer leaving an air/empty space between the wad and the base of the bullet.  Doing thus, loading for lower velocity, with medium to heavy bullets for caliber is the primary cause of "ringing" in my estimation.   

As an example using the 30-06 with cast bullets;

if a 170 - 220 gr cast bullet is being used with 4895 powder seeking the best accuracy I recommend the use of a Dacron filler (3/4 - 1 gr).  That will cause the 4895 to ignite and burn consistently giving velocities in the 1700 to 1940 fps range where the best accuracy will be found with that combination. 

If a 140 - 165 gr cast bullet is being used and it is desired to push to 1800 - 2000 fps I would not recommend 4895 as it most often will not ignited and burn efficiently even with the Dacron filler because the lower mass of the bullet will not allow the pressure to rise to its efficient burning level.  A faster burning powders such as 2400, 4227, 4198, Rl7 and perhaps even 3031 would be recommended.  There are other powders also but you get the idea of the burning range. With those the load density is low (less than 80%) so the Dacron filler is advised.

If a 90 - 130 gr cast bullet is being used with desired velocity in the 1200 - 1500 fps range +/- then I recommend a faster powders in the burning range of Unique to Blue Dot. No filler should be needed or used.

With 90 - 220 gr cast bullets in the 600 t0 100 fps range I recommend Bullseye or Red Dot.  No filler is needed or should be used.

Let me add too that the style of shooting one does can also affect whether a filler is needed or not.  If bench shooting where the rifle stays in position the use of many powder/bullet combos do not need a filler if the loading procedure for each round is consistent, particularly if the loading procedure positions the powder consistently at the rear of the case.  This also can be done when position shooting, as mentioned in another post, during slow fire events.  However, as also previously mentioned, if used in repeating guns which load from the magazine, w/o such consistent positioning of the powder, the benefit of the filler becomes self apparent in the improved accuracy.   When hunting or field shooting where the rifle may be shouldered from any carry position the filler keeps the powder consistently positioned for better accuracy also.

Thus we see the use of a filler is not applicable in all loading situations.  It is applicable where beneficial.

LMG

 

Concealment is not cover.........

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John Alexander posted this 1 weeks ago

I think the follow up discussion has put fillers and what some are calling fillers in perspective and will give fair warning for when filters may possibly be helpful and when some things commonly called filters may ruin your rifle.

Larry's definition of the dangerous type of fiber use as "wads"  or Ed's and Allan Jones's term of  "puffballs" is a good idea but shooters should be aware that this type of use is often called "filler" including in the title and body of Jones's article.

Thanks to all for making the distinction clear and possibly avoiding some ringed chambers.

John

 

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Ed Harris posted this 1 weeks ago

This is a subject which needs to be repeated from time to time for the passing parade who didn't "read the memo."  Thanks again Larry for the clarification. 

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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OU812 posted this 1 weeks ago

What is a ringed chamber or chamber ringing?

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R. Dupraz posted this 1 weeks ago

Thanks Larry for clarifying the difference between "filers" and "wads" and their use in reloading. After reading your latest reply and re-reading my post regarding that Shiloh Sharps 45-70 I can see where there  could be some confusion with what I wrote.

My motivation was Ed's description of those ringed chambers which were exactly the same as that sectioned 45-70 barrel. And even though this club's members that I knew loaded black in their BPC rifles exclusively, We will never know for sure what the original owner did to cause that ringed chamber in the 45-70. 

It could have been the improper use of wads while loading BP or smokeless or fillers or some other combination. But I think that it is safe to say  that the original owner did something out of the ordinary to cause those rings.

What ever the cause, that is why, being the overly cautious pigrim that I am,  have chosen a long time ago to stick with the commonly accepted loading procedures, both with smokeless and black.

Hope this makes my post a little clearer. 

 

R.

 

 

 

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OU812 posted this 1 weeks ago

Do NOT USE DACRON OR ANY FUZZ BALL FILLER! THEY ALMOST GUARANTEE A RINGED AND RUINED BARREL!

http://www.go2gbo.com/forums/99-ask-veral-smith-lbt-q/160462-fillers-light-loads.html

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joeb33050 posted this 6 days ago

What is a ringed chamber or chamber ringing?

A ring is a groove around the circumference of the chamber. Some contend that these are caused by Dacron fillers, with explanations that involve physics. Ed ??, a gunsmith then in Lakeville MA, said repeatedly that chamber rings were caused by chips on chambering reamers, and had new rifles with chamber rings to prove it; one a Ruger #1.

Charlie Dell did an extensive experiment proving that light Dacron balls ring chambers; but reading the story is not convincing.

I shot thousands of  30/06 cast loads with a teased ball of Dacron about nickel-sized pushed down, with a pencil, on 12/Unique; Dacron weight ~ 1 grain-never ringed a chamber. 13/14 Unique eliminated the Dacron. Many others went down the Dacron trail after Harrison's book , later left Dacron to the garment makers.

And the beat goes on.

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Ed Harris posted this 6 days ago

If you go through back issues of American Rifleman, you can find one of the more interesting lengthy discussions on chamber ringing. This did not involve use of case fillers at all, but occurred with .30-'06 Ball M2 ammunition.  The subject lots of ammo were originally manufactured in the early 1950s, using WC852 Ball powder and were recalled by the DCM.   The article shows sectioned M1 Garand barrels having the ring, and rub marks on ejected case necks where hard extraction occurred.   

The 152-grain Ball M2 bullet is flat-based, and when loaded in the .30-'06 case positions the base well up into the neck.  With the particular loading of WC852 powder there was considerable airspace in the case, and it was found that when fired in the M1 Garand, with the powder positioned to the rear of the case, as normally occurs during the slow-fire stages of the National Match Course.

In testing by the Army, when the Garand was fired in the normal manner, such that its vigorous bolt closure positioned the powder charge forward in the case, no chamber ringing occurred.  The conditions of significant airspace existed only when the powder charge occupied less than about 85% of the available powder space and the charge was oriented in "base tap."

I personally had an M1 Garand in which the chamber was ringed using cal. .30 Ball M2 firing SL52 and 53 ammunition of the affected lots.  Military armorers at Camp Perry inspected rifles with bore scopes and members of affiliated clubs who obtained DCM ammunition of one of the affected lots could have their rifles rebarreled at no charge.  Mine was in 1967.

Later when I was on the NRA staff Bob Sears, Ken Raynor, Joseph B. Roberts and I also experienced ringed chambers attempting to approximate a Ball M2 load using Hodgdon H335 and also with W748 powder.  A nominal charge of 50 grains of either produced the desired velocity, but ballistic uniformity was not as desired and varied depending upon powder position.  During the course of testing we also succeeded in ringing the chamber of a Winchester Model 70 target rifle being used to test the loads. While firing the offending military loads in the Garand produced no functional or safety problem, once a noticeable chamber ring occurred, hard bolt lift was evident during primary extraction, and increased effort was required to extract the fired case.  

NRA Contributing Editor William C. Davis, Jr. was the former director of the U.S. Army Small Caliber Laboratory when it used to be at the Frankford Arsenal.  He recognized the condition immediately and related the story of WC852 Ball powder in the Garand.  He explained that this condition had been thoroughly investigated in separate-loaded artillery and occurred when the origin of rifling advanced due to extended firing, such that free airspace occurred behind the projectile it was seated against the leade and a normal charge fired behind it.  Much work in this regard was done by the British Army Royal Ordnance Laboratory at Woolwich.

The solution was to pull tubes out of service when the leade advanced to a point measured with a bore erosion gage.

Davis opined that in our cast bullet loads that if a particular powder required use of a filler for ballistic uniformity, that it probably wasn't suited for those conditions of loading.  The culprit was not the filler, but our attempts to use powders which did not tolerate free airspace in the case well.  Davis suggested that tucking "loose fill" to take up the free air space help mitigate the condition, but that in his opinion, pushing the filler down against the powder, leaving the free air space unabated in front of the charge, was a contributing factor in chamber ringing.  But he was always sure to point out that if the powder is unsuitable for the loading conditions, that no filler is needed at all for chamber ringing to occur.  It may not happen in one or a few shots, but if you experience any noticeable delayed ignition, noticeable hangfires, or sample velocity standard deviations which exceed about 10% of the sample mean, these should be heeded as a clue.  

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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Larry Gibson posted this 6 days ago

 OU812

If you read Veral's post prior to and including that post you see he is adamant that the filler must fill the space between the powder and the bullet base completely.  He even recommends some compression. Veral's blanket statement which you quoted is not the same as he is actually describing the use of a "wad".  In his next post on that forum he further explains;

"The puff ball starts the powder burning fast, but also acts as a projectile/piston on the air between it and the bullet."

That quotation from Veral's post is a definition of a "wad". Note the highlighted part.  What he is doing is using "filler" to also describe a "wad" which is a classic error in a discussion of using fillers.  The two, fillers and wads,  are different, very different. In my previous posts the difference has been well described.

Veral, in that thread, also does not delineate when not to use a filler (of any material) with certain loads and certain powders.  I agree with 45 2.1 in that I also have used Dacron as a "wad" in thousands of cast bullet loads with faster powders, most often Unique, in numerous cartridges from the 222 Rem up through the 45-90.  I did so w/o any "ringing" of any chambers.  Thus Veral's "almost guarantee" doesn't quite hold up.  As with 45 2.1 I also did not find Dells work (I have read and studied it numerous times) to be totally convincing either.   

I went from using Dacron as a wad to using Dacron as a filler for a completely different reason that the possibility of "ringing". I also have thoroughly tested it over the years with numerous burning rates of powders in various cartridges with cast bullets.  In chronographing many thousands of such loads over the last 42 years plus actually measuring pressures the last 9 years I have not found a single anomaly attributed to the proper use of a Dacron filler.  Yes, with the improper selection of powder used with a filler,  I can easily create dangerous pressures but anyone can, by design or by accident. 

The point is a filler, Dacron or some other material, is not a panacea to be used all the time.  A proper material used as a proper filler is beneficial if used appropriately with the correct cast bullet and powder burning rate. In reloading ammunition we make choices continually of which powder to use for which bullet and how much of that powder to be safe.  Making the wrong choice and improper use can indeed be dangerous to firearm and the shooter. Make the right choices and using those choices correctly the reloaded ammunition is perfectly safe. It is exactly the same with the use of a filler.  Make the correct choice and use the filler correctly and it is perfectly safe.  Make the wrong choices (of powder and filler material) or use the filler incorrectly (as a wad) and it can be dangerous perhaps by just "ringing" the chamber.

The proper use of Dacron as correctly a "FILLER"  poses no problems and is most often beneficial to accuracy.  Using kapok or the synthetic buffer materials as "fillers" also poses no problems when done correctly.  I do not recommend the use of organic materials (COW, coffee, etc.) as they can easily raise pressures (actually measured) above what is safe for some firearms.

LMG

Concealment is not cover.........

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John Alexander posted this 6 days ago

Larry,

I have no quarrel with you insisting that using fluff so there is air space between it and the base of the bullet should be called a "wad" or "puffball" instead of calling it filler. I agree that those are better terms. But many people including professional ballisticians are going to keep calling the practice "filler". 

We are not going going to get people to stop using the term incorrectly any more than we can get writers to stop using "price point" instead of "price", "optic" when talking about a 10X rifle scope, or saying "engage" when they mean "shoot at". It may be wrong but people will do it anyway. So it is good idea to always make it clear that what some people call filters can can causing ringing.

John

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Ed Harris posted this 6 days ago

I did a Google search trying to find any published studies on artillery tube bursts as a result of "reflected longitudinal pressure waves" but I'm afraid the Watervilet Arsenal and Woolwich work from UK doesn't exist on the Internet.  I did find a couple related studies in other applications:

http://shepherd.caltech.edu/EDL/publications/reprints/136_ina.pdf

Impact generated stress waves and coupled fluid-structure responses Kazuaki Inaba, Postdoctoral Scholar, Graduate Aeronautical Laboratories Joseph E. Shepherd, Professor, Aeronautics and Mechanical Engineering California Institute of Technology 1200 E. California Blvd, Pasadena, CA 91125, USA joseph.e.shepherd@caltech.edu ABSTRACT We are studying strongly-coupled fluid-structure interaction generated by a stress wave propagating along the surface (as opposed to the usual case of normal incidence) in the fluid adjacent to a thin solid shell. This is realized experimentally through projectile impact along the axis of a water-filled tube. We have tested mild steel, aluminum (6061-T6), carbon-fiber (CFC), and glass-reinforced plastic (GRP) tubes 40 mm diameter and 0.8 mm wall thickness. A steel impactor is accelerated to 5–20 m/s using an air cannon and strikes an acrylic buffer or a polycarbonate buffer within the tube. Strain gages measure hoop and longitudinal strains every 100 mm. Elastic flexural waves are observed for impact speeds of 5–10 m/s and plastic waves appear for impact speeds approaching 20 m/s. Plastic flexural waves caused rupture of Al and CFC tubes at the closed end of specimen although the wave speeds were close to those predicted by the simple Korteweg theory. 

http://shepherd.caltech.edu/EDL/publications/reprints/kazuakiinaba_ICCM17_final.pdf

FAILURE OF LIQUID-FILLED FILAMENT-WOUND COMPOSITE TUBES SUBJECTED TO AXIAL IMPACT K. Inaba† and J.E. Shepherd‡ †Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8552, JAPAN, inaba@mech.titech.ac.jp ‡California Institute of Technology, 1200 E California Blvd, Pasadena, CA 91125, USA, joseph.e.shepherd@caltech.edu SUMMARY We have studied the damage and rupture failure of water-filled filament-wound composite tubes due to stress waves generated by fluid-structure interaction resulting from axially-directed projectile impact on the water. Onset of the failure appears to be transverse cracking for the 45◦ tubes and through-lamina cracking for the 60◦ tubes.

http://www.arl.army.mil/arlreports/2009/ARL-TR-4838.pdf   Mortar Interior Ballistics: Sensitivity Studies Using IBHVG2 and Progress Toward a Multidimensional Representation 

 ABSTRACT Traditionally, the interior ballistic (IB) modeling of mortars has been difficult to achieve because a mortar projectile contains certain energetic components internal to the tail boom. After ignition, high pressure generated by the igniter causes the canister to burst and release hot gases and burning particles into the larger chamber called the launch tube. Subsequently, any external charges ignite and produce gases which accelerate the projectile. A recent advancement to the IBHVG2 code allows the modeling of this high-low (HILO) configuration. This HILO feature comes with the introduction of two new parameters into the IBHVG2 model, essentially gas-phase and solid-phase discharge coefficients governing flow between the two chambers. The large-caliber gun community focuses on the impact of seven IB input variables (charge weight, force, propellant diameter, burning rate coefficient and exponent, covolume, and projectile weight) on the peak chamber pressure and projectile exit velocity. A sensitivity study on these input variables was performed on the high and low canister over a small range of the nominal value. The HILO feature was also examined for a 120-mm mortar. Uncertainty associated with the two new free parameters necessitated a wider range of investigation of said parameters.

 

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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Larry Gibson posted this 6 days ago

John

No doubt you are correct, we will probably not change most of the verbiage misuse of the term "filler", especially among gun writers.  However, we can continue to point out the error in the use of "filler" when it is a "wad" that is described and point out that the correct term should be used.  If not the continual misinformation (myth) will persist and most often emphasized with the "oh my gosh, the sky is falling" type statements concerning "ringing" such as quoted. 

I don't care if some chooses not to use a filler for what ever reason, that is their choice.  But I do not agree with denigrating the proper use of a filler with the mistaken concept of a wad.  The proper use of a filler is perfectly safe. We can also assist those who wish to reap the benefit of a proper filler use by noting what is correct and what is not.

LMG

 

 

Concealment is not cover.........

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45 2.1 posted this 6 days ago

There is an interesting article in the July 2018 Shooting Times titled "Fillers for reduced rifle loads" by Allan Jones, the Speer ballistician. His summary agrees with mine.

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RicinYakima posted this 5 days ago

The pressure at one point in the chamber is so high, that it forces the metal of the barrel outward. It is 90 degrees to the bore axis. Then every time a brass case if fired in the chamber, it forces the brass case into the void and prevents or restricts removing the case.

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