Fillers

[Zeek]

Here are three responses from my friend Mic McPherson when we got to talking about using filler materials, such as dacron. I thought that you would want to see it.

. . . The use of any synthetic filler such as Dacron is only asking for a destroyed gun. Just a matter of time before the chamber is either ringed or the gun is completely destroyed. THIS IS A MONUMENTALLY DANGEROUS PRACTICE.

I once wrote of this problem in a PS (Precision Shooting Magazine) article. Within one week of that piece's being published, I had three calls from experts who "had been doing that for decades... and never had a problem." Within three weeks thereafter, two of those guys called me back to apologize for they had just ruined a gun by ringing the chamber. A ringed chamber is exactly one infinitesimal step from a failed gun -- the classic detonation.
Thanks, Mic

ADD-ON: I asked him about COW and CM fillers too, pointing out the danger of decreasing the effective case capacity, relative to the given propellant charge. Here's what he indicated:

Organic fillers are monumentally less dangerous. However, no one can predict the ballistic consequences -- the filler might very well decrease chamber pressure! Why? Because it might promote primer induced bullet movement. However, any such filler has some percentage of rather abrasive inclusions. The only well proven safe filler is florist's foam -- it is cellulose based and crushes to produce dust that is not abrasive. Using anything else is just foolish.

Why is Dacron and such so dangerous? Because it compresses to almost no volume when the primer blast hammers into it. Then is melts. Both processes absorb a huge amount of heat from the primer blast, leaving less to ignite propellant. Also, the entire charge is then located at the bullet end and. Inadequate ignition is responsible for all detonations and the Krupp commission proved in its 1888 tests that any cylindrical cartridge with a partial case filling charge located at either end of the chamber and then ignited will always generate a standing wave -- whether the peak of this standing wave grows narrow enough so that the force at the center of the peak exceeds the strength of the chamber depends upon an entire hoist of variables but the potential is always present. So, synthetic fillers are doubly dangerous and it amazes me that folks do not know this!
Mic

Now, most folks have opinions, but Mic is the fellow who wrote the algorithms for the popular QuickLOAD software. He really knows what he is talking about, when it comes to internal ballistics. He's a very private fellow, so please don't bother him by e-mail except to arrange for him to do work on your lever action rifles. His essential "fix" is to use florist foam for a filler, which is cheap and readily available. You'll get LOTS more by reading his articles and book. That is the best way to obtain, and make use of, his input.
Thanks, Zeek

[longbow]

Zeek:

I am interested in fillers but of the granular type.

There is a thread on loading with fillers for the 6.5 Swede that I have been following. Larry Gibson is doing some pressure testing using shotgun buffer.

I have read articles on using shotgun buffer and cereal fillers and so far no mention of ringed chambers of pressure signs as long as loads are worked up.

Do you have any information on use of granular fillers like cereal fillers, shotgun buffer or Pufflon?

I would be very interested in any information you may have and I am sure there are others interested as well.

Longbow

[303Guy]

Zeek

This got my attention as I am fond of using fillers of the cotton wool type!
Quite honestly I thought the biggest danger was setting the bush on fire! (I did once get smoldering cotton wool but usually it doesn't even scourch).

Are there more details on what or how the chamber ringing occured? Mic says 'detonation' but what were the actual conditions? Was there a fibre wad over the powder with an air gap under the boolit? Where in the chamber did this ringing occur? Had the boolet slipped back into the case some and obturated inside the case? Too many questions!

I've seen it written that certain powders should not be reduced too much without the use of fillers because loose low volume charges can result in detonation. That appears to contradict Mic but not if we knew the actual conditions.

[barrabruce]

I've read stuff on the interweb.
One side=no fillers.
Other side no dramas if done right!!!


Anyways as far as I can tell...which anit much.
Trouble comes from the slower or non compatable reducing powders.
Apparently if you drill the primer pocket out it is suppose to get a better flame pattern and ingition.

A rimless case is used and the headspace gets to large from the primer forcing the shell forward and not having enough to blow back the base and reseat the shoulder to specs.

A wad is not placed on the powder and the rest of the case filled.
Meaning a wad with a gap or gaps occurr. This can form compact mass which hits the base of the bullet in a hard form under momentum and can cause ringing.As most of this ocuurs where the bullet was seated.(one theroy)

ITs all in the lap of the gods to me...
Iv'e just stuck to what the others do and pray I got it right.

Barra

[pdawg_shooter]

I have had my best loads by choosing a slow enough powder to get as near as possible to 100% load density. That way I get the best accuracy, jacketed velocity, and no need of fillers.

[303Guy]

I too like the slow enough powder to fill the case but most of my 'test tube' testing is done with light loads of fast powder that needs to be held against the primer. Now I am developing a sub-sonic hunting load and I seem to have no choice but to have a ¼ to ½ filled case. (Unless I can reduce the case capacity somehow and use a slower powder).

[Larry Gibson]

I've researched this numerous times over the years. Every instance of documented chamber ringing involved the use of wads, almost always a card wad of some kind with lots of space between the wad and the base of the bullet. There is a big difference between a wad and a filler but many do not understand the difference. A good example of the confusion is the use of shotgun wads in shotshells. In reality they are fillers in the context of what they do inside the shell. BTW; I never could document a single case of a ringed chamber from a dacron wad, can anyone? I prefer documented not hearsay.

Larry Gibson

[yondering]

Does your friend Mic have any explanation to offer behind his statement?

I've sometimes used a small tuft of cotton to hold the powder back against the primer; for example 10gr of Unique in a 30-06. I have a hard time picturing how that tiny pinch of cotton can cause chamber ringing or "detonation", vs just the loose powder sitting against the back of the case. I'll believe it when I see documented scientific proof.

[303Guy]

Well, I can think of one possibility. If the powder granules manage to work their way through that tuft of dacron so that there are two effective powder charges separated by dacron, the first might burn quicker and set off the second at a much higher temperature and pressure. That could be described as 'detonation'. But that would only cause ringing of the chamber if the boolit base upsets under the sudden pressure rise while it is still within the neck. That's only hyper-speculation. I have once found evidence pointing to powder granules working into the filler - when the filler ignited. Even that is speculation! I now make sure the powder won't ingress the filler and I haven't had burning filler since. (Cotton wool - the stuff can smolder quite sneakerly).

[shooter93]

Charlie Dell did pretty extensive testing on the subject and makes a very convincing argument as Mic does if you've read his stuff. Both of those guys are hard to argue with considering how extensive their tests and test methods are. Charlie's research is in his book on Schutzen shooting. Personally if I think I want a fillers I use Puff-a-Lon. It weighs nothing so you don't have an added weight problem and you use enough to fill the case with a slight compression. It seems the not filling the case part is where the problem lies.

[longbow]

My understanding agrees with shooter93. It is a large empty volume that leads to trouble.

I am not stating that as a fact but as my understanding of the issue.

By using a filler, there is not a large empty volume anymore and 100% loading density is achieved. Yes, you have to add the filler weight to the boolit weight and you can't just add filler to an already full load just because there is some empty space.

I guess there is going to be some compression and extrusion of the filler through the cartridge neck but then with a full case of slow powder, the powder does not all burn in the cartridge so is going to be compressed and forced through the neck too ~ like a granular filler.

The uses I see are:

- very light charges for subsonic loads (eliminating the position sensitivity of some powders)
- preventing double charging using reduced loads
- achieving 100% loading density for use with reduced charges of slow powders (no SEE effect and more consistent burn) ~ not everyone wants a full house load all the time
- eliminating gas checks
- minimizing or eliminating leading (seemingly a happy byproduct of using granular filler)
- sealing behind the boolit to prevent gas cutting with boolits that may be undersize or in bores that are rough
- allowing higher than normal cast boolit velocity

I can think of lots of good uses and so far I have had no problems using granular fillers with any of fast, medium or slow powders. However, I do not want to take chances so would like to hear from others. I am not looking to ring a chamber or blow up a gun.

I do not have pressure testing equipment so can only start with light loads and work up to where I want to be unless flattened primers or sticky extraction say otherwise. So far I have not pushed the limits for high velocity so that has not been a problem.

I have been following the 6.5 Swede test Larry is doing with great interest.

FWIW

Longbow

[bcp477]

The warning issued by the author quoted is an ENORMOUS oversimplification. As someone else stated before, many do not understand the use of fillers. If one does not understand how to use them - THEN DON'T. It is ridiculous to assert that the use of fillers will certainly lead to chamber ringing....or a "destroyed gun". Bloody nonsense. The use of fillers INCORRECTLY could lead to such problems..... the key word being "incorrectly".

I've been using them for years - dacron and cotton wool exclusively. I will continue to do so, as I DO understand their use..... regardless of the misgivings of any "expert."

[Zeek]

Longbow asked

I am interested in fillers but of the granular type.

Dear Longbow: see revised starter blab for this thread. Zeek

303GUY indicated:

This got my attention as I am fond of using fillers of the cotton wool type!
Quite honestly I thought the biggest danger was setting the bush on fire! (I did once get smoldering cotton wool but usually it doesn't even scorch).

Are there more details on what or how the chamber ringing occured? Mic says 'detonation' but what were the actual conditions? Was there a fibre wad over the powder with an air gap under the boolit? Where in the chamber did this ringing occur? Had the boolet slipped back into the case some and obturated inside the case? Too many questions!

I've seen it written that certain powders should not be reduced too much without the use of fillers because loose low volume charges can result in detonation. That appears to contradict Mic but not if we knew the actual conditions.

A: I'll ask him about wool, given that it cannot melt. Recall, though, that the warning was about having all the powder at either the front or the rear of the cartridge.

Many more comments/questions by All Y'awl (that guy sure can talk!).
Let me refer you to Mic's website. Look at all of his articles posed there. This guy is the real thing, so you will not be wasting your time on a snow-shovel expert:
http://www.leverguns.com/store/mcpherson.htm

I just tried this just now & it would not function. Try again later. Given that I am not Mic, I'll just let this thread rumble on as a talk place about this subject and what you find out about it.

BTW, I have had Mic give his full or near-full treatment to ALL of my leverguns, and they sure work nicely now. Also, do NOT miss out on his book (available through PS: http://www.precisionshooting.com/books.html ) on Accurizing the Factory Rifle. LOADS of stuff in there that you have NEVER heard or thought of before!

Keep in mind that he is not talking about deflagration (fast burning that propagates no faster than the speed of sound). He is talking about conditions that can ring-or-render-into-many-parts the rifle: explosion. Rifle powder deflagrates, except under certain circumstances. Let's avoid those circumstances, guys, okay?
Zeek

[405]

No worries about flame blame. It's good to get all sides and opinions about this. If for no other reason than to keep the wits sharp and gray matter limber. Everyone gets into ruts and a tunnel vision syndrome as things go along, shooting goes well and guns don't blow up. Good to think and re-think in abstract once in a while.

A good point is made about... if the premise were true about the potential for fillers causing all sorts of maladies then how can wide varieties of shotshells function properly with all manner, design and types of plastic or fiber fillers?

I do think detonations can happen... but they are very rare. Can most kabooms be traced to simple over-charge/over-pressure? I do think ringing can happen. Is it more of a result of kinetic/mechanical obturation happening right at or involving a thin wafer like zone of solid material of the bullet base or hard wad or both? Can a compressed solid mass of unburned powder, slamming against the bullet base, cause a similar condition resulting in a ring?

A few years ago I looked at some raw lab data published by one of the Scand. powder/ammo/gun companies- Lapua or Norma or Sako maybe??? no matter, they used the most modern ballistic testing equipment available and were trying to duplicate conditions that were causing "reported" detonations. They couldn't cause one in the lab! The closest they came to detonations were abnormalities seen in "shadow graph" images from inside a cartridge case as the round fired. They occassionally observed a high velocity compression wave impact the base of the bullet then move rearward into the main powder charge. I can't remember all of it but I think they saw squirrely pressures when that condition was observed. One thing I do remember though is that they could not reliably duplicate or repeat the rebounding compression wave situation. It seemed to be fairly rare and almost random.

[StarMetal]

Just because the fellow is famous for doing something else doesn't mean he's the Holy Grail on fillers. Not myself either. I think he's full of it. It's been said that Dacron burns and often leaves little melted plastic like balls in your bore. I've never found this. BruceB finds a lot of his Dacron filler in front of his shooting bench and only slightly charred. I see most of mine blow out with the muzzle blast like blowing on a dandelion. I too feel the problems are from using it wrong. I don't buy the primer pushing out the filler and bullet either because if that were true our Swede project with the buffer wouldn't have the shock absorbing effect it does on the bullet. BruceB and my self have done test with Dacron loaded in clear plastic vials with powder. In my case a fairly fine ball powder. Bruce carried his in his pocket for a couple weeks or something like that. Me I vibrated, tapped, jarred mine. Nothing, no migrations. I done the same test with shot buffer and course tubular powder. Nothing. I don't see a filler decreasing pressure.

Longbow why follow Larry in the Swede loading, just pm me and I'll help you along the way and you can be shooting yours.

Joe

[Willbird]

From what I had read about ringing of chambers it happens more often with guns that have very soft steel barrels (not 4140). of course these guns are typically WORTH a lot more $$ too .

Bill

[303Guy]

Wow! This sure is an interesting thread. It might just save one of my Lee Enfields! Not to mention my dignity.

Mmmm.... food for thought. As 405 puts it - grey matter stimulation and waking up from a rut!

That random compression wave is a worry since if it were to coincide with some other random adverse condition the results might be unexpected!

Thanks for bringing this up, Zeek.

[StarMetal]

I talked to one of the Hodgdon powder techs about the old classic blowing up your 38 Special with hollow base wadcutters and small charges of Bullseyes. He said they tried to duplicate that in the lab really really a lot and nothing. He said they would bet if you could go back in time and take the cartridge apart you'd find more powder in there then was suppose to be. I tend to agree.

303guy, you've stuck stuff in your cases and shot them that I'd never ever do.

Joe

[303Guy]

303guy, you've stuck stuff in your cases and shot them that I'd never ever do.

And I wouldn't recommend anyone doing what I do either!

I'm wondering how I've managed to survive this far! I think thing through carefully though. That's why I take note when a warning is sounded! I also like to look closely at other peoples boo boos so that I can understand how not to make the same mistake. Sometimes I actually manage to save myself but I also often show others what not to do!

I'm glad you mentioned your tests with powder migration through a filler. Have you done similar tests to see how not to use a filler? Meaning, to see what conditions will allow the filler to migrate?

He said they would bet if you could go back in time and take the cartridge apart you'd find more powder in there then was suppose to be.

This has been my contension too! It's human nature to water down what we've done when we blow something up - it's an attempt to save face!

[StarMetal]

And I wouldn't recommend anyone doing what I do either!

I'm wondering how I've managed to survive this far! I think thing through carefully though. That's why I take note when a warning is sounded! I also like to look closely at other peoples boo boos so that I can understand how not to make the same mistake. Sometimes I actually manage to save myself but I also often show others what not to do!

I'm glad you mentioned your tests with powder migration through a filler. Have you done similar tests to see how not to use a filler? Meaning, to see what conditions will allow the filler to migrate?

This has been my contension too! It's human nature to water down what we've done when we blow something up - it's an attempt to save face!

No, all I wanted to see if powder would migrate and if buffer would migrate. I imagine if you carried them for years or handled them rough for months on it would migrate though. But in normal handling and use...no.

Joe