There are a couple of pieces of information that are being left out of this discussion. 
First for the purposes of testing Charlie made barrels out of brass. This was done so that the slightest ring left could be measured. He believed that most chamber ringing was done over time not in one catastrophic event that is what he was trying to study. 
The other thing is that when Charlie loaded the powder was ALWAYS oriented against the wad and the powder was allowed to slump at the rear of the case. Charlie was a bear on this one point. When others assisted him he never failed to double and sometimes triple check to make sure that this was done. 
I sat in on hours of the chamber ringing discussion and I will freely admit that sometimes we got so far out in the weeds I had a hard time finding my way out. Or it may have been the bourbon. The point is I got to hear it from the horses mouth. There is a lot said here that frankly is the writers interpretation of what is written, not what is actually there. I suggest that everyone read the entire chapter carefully with an open mind, not to confirm some personal notion.

A little bit of knowledge is a dangerous thing...so drink deep.
40 Rod

I just read the chapter (17B) in Charlie Dell's book, twice. 
I have read everything I can find on chamber ringing, and solicited opinions and experiences on the topic. Much of that is in the book.
Here's my question: Using a rifle with a "normal" load of smokeless powder and a Dacron wad on the powder, will the chamber acquire a ring?
With the greatest respect for Charlie, I'll say what I've said before. Charlie's book/chapter/experiments do not, in my opinion, answer the question.
What happens in a 38-55 blowing out 30-30 cases with 10/Bullseye and a 95 grain bullet
or 
38-55 with 38-55 cases , 10/Bullseye, .06" cork wad and ????bullet
or 
with a brass chamber insert
doesn't answer the question.
I believe that about any independent reader would not find the C. Dell argument convincing.
I do not know if normal load chambers ring.
I have yet to find any account of a rifle being fired multiple times with a normal load and 1 case, the case and chamber inspected and found to be ring-free, then fired multiple times with the same load and a Dacron or ? wad, and  a chamber ring appearing.
Ed Landers was/is a pretty good gunsmith. He believed that chamber rings were caused by a chip in the reamer during chambering.
I believe that Charlie did the tests, and got the results reported. 
I do not know if any wads in any position cause chamber rings. I recommend that wads NOT be used. But I would point out that putting wads .0x0" off the powder and firing the gun repeatedly without chamber rings does NOT prove anything.
I will be happy to send copies of Chapter 17B to anyone wanting one.
joe b.

The tests started out with the use of 1985 barrel in 38-55 that was beyond repair with a clean chamber. Charlie was trying to replicate the procedures used by another shooter who rung his chamber while blowing out cases for his 38-55. That gentleman was using 10grs of Bullseye, a 95gr. Bullet in the case mouth and a tuft of Dacron fiber weighing.0.3 grains to hold the powder near the case head with the intent of building pressure to form the cases. Skipping along a ring formed the chamber was cut off and sectioned in the mill for microscope inspection. Barrel was re-threaded chambered and further tests were preformed with the case being sectioned to examine the rings being formed. Charlie wanted something weaker to make the tests more sensitive so that a lesser number of rounds would have to be fired to produce comparable effects. He settled on an annealed brass chamber insert with a Rockwell B hardness of 42 plus or minus 5. He moved on with the use of 240 grain bullet and all tests were with fixed ammunition with a 1.728 dimension from bullet base to breach face. The ringing always took place at the bullet base so the length of the cartridge was determined not to be a factor. Different materials were used to retain the powder at the case head and in all cases when the powder was held back against the cartridge head a ring developed and it was always at the bullet base. The test confirmed that the ring was not caused by the wad material impacting the base of the bullet. The basic cause of ringing is that a coherent column of high velocity gas and burning powder with considerable kinetic energy when hitting the stationary bullet has to stop and in the process generates a thin ring of stationary very high static pressure under the well know law regarding the conservation of energy.

Continued

Charlie performed these test with the assistance of two engineers one a retired rocket fuel engineer and the others specialty was not noted as well as the help and input from his several friends. The brief description I posted was out of the book while trying to get quickly to the point / bottom line and I would encourage buying the book and reading this chapter in it's entirety as there is allot more to it than I could supply in my very brief posting. The critical part is the slump in the powder and having the powder forward towards the mouth of the case or near the rear of case did not matter. Anything less than the 0.20 standoff created a ring with a .010 standoff being less severe yet still forming a ring with the wad directly on the powder having the severest affect.

J.Louis

If Charlie's experiments and explanation work for you, great. I have no hope, expectation or desire to convert anyone. This topic has been discussed to death.  I will only say this. Since the NRA "Cast Bullets" and Lyman's 3rd cast bullet handbook-the early 70s, a lot of shooters shot a lot of cast bullets with Dacron wads. I shot thousands of 30/06, 45-70 and other cartridges with Dacron wads. I never got a chamber ring. It's my experience and that of the thousands of others with no rings that makes any explanation or solution fuzzy.
The core of scientific experimentation is replication-if A can make it happen, B has got to be able to make it happen or A proved nothing.
If it works for you, have at it.
joe b.

joe,
If your loads with Dacron were at 60% (maybe even 50%) load density or more, I don't believe you would have had a problem. I shot my 30/40 at about 30% with a soft foam wad (1/16 thick x 1/2" sq) and "rang" my chamber, not at the bullet base but, just back of the shoulder.

Two friends of mine shot loads of 60 - 70% powder and shot thousands of rounds (between the two) with that very same wad and never had any issues.

I got the idea from them and my loads chronoed better but, I only got less than 100 rounds shot before it happened to me.

This happened to me about 1990 in preparing for CBA matches and before I new better. I wish that CD had done his work earlier so, I would have had a warning.

Lyman no longer recommends ANY wads or "fillers" for cast bullets for this very reason. I believe that guys can get away with the Dacron wad either because there loading density is high enough or because the amount of Dacron is small enough to still let the powder slump. There is at least one guy over on "Cast Boolits" that has "rang" a barrel using Dacron.

Also, it's spilt about evenly (for people that have tried it) as to whether wads or fillers in reduced charges, contribute to accuracy. My chono results show it can decrease ES and SD but, not increase accuracy. As you know in experimenting, you can prejudice your results and I beleave that is why a lot of people are advocates of Dacron but, when it happens to you, you don't care if you think it could be more accurate.

Let me put it this way, CD's work means a lot more to people that have "rung" a barrel w/wads than to those who have not!!!

Frank

I want to add through my personnel experience while experimenting with wads in my 32-40. Placing one of different compositions such as cork and floral foam down on the powder has made the web of the case swell to the point of extremely very hard extraction. I believe this to be a pressure spike and or sending the pressures through the roof as I don't have any other explanation for it. I load at the second node being very close to the 1500fps range, of which might be considered by some to be on the high / hot side. I have not tried it at the first node closer to the 1300fps range so I cannot comment about the affects with the milder charges. I bring this up because those who are using an action that is not as quite as strong as my CPA's as well as others might be flirting with a much bigger disaster than just ringing their chamber.

J.Louis